Optimisation des prescriptions pour les personnes âgées

Conférencier : Allen R. Huang, MDCM, FRCPC, FACP, professeur agrégé de médecine, Université McGill; directeur du service de gériatrie, centre de santé universitaire McGill, Montréal (Québec).

Le D^r Allen Huang s’est intéressé aux problèmes particuliers des prescriptions médicamenteuses aux personnes âgées.

Pourquoi les prescriptions aux personnes âgées sont-elles problématiques?
Le D^r Huang a souligné à quel point une prescription médicamenteuse de base peut s’avérer compliquée lorsqu’on a affaire à un « cas classique » de personne âgée :

Une femme de 85 ans est amenée aux urgences par son époux. Elle est confuse, souffre de nausées et de vomissements, et est très mince, ce qui correspond à un syndrome souvent appelé « détérioration générale ». Son mari signale que son état a récemment empiré, qu’elle a plus souvent besoin de son aide pour les activités de la vie quotidienne, et que sa vivacité fluctue dans la journée. La patiente souffre des troubles médicaux suivants : diabète, hypothyroïdisme, hypertension, insuffisance cardiaque congestive, fibrillation auriculaire, antécédents d’accident vasculaire cérébral et antécédent de deux décennies de polymyosite. À l’examen, elle présente une TA de 110/70 et un faible pouls de 40 battements par minute. Les épreuves de laboratoire les plus anormales incluent : RIN = 8,3; taux de digoxine sérique = 3,24 nmol/l; TSH = 0,24; clairance de la créatinine = 21 ml/min.

Elle prend actuellement 13 médicaments différents : warfarine : 2,5 mg 1 f.p.j PO; di- goxine : 0,25 mg 1 f.p.j PO; hydrochlorothiazide : 50 mg 1 f.p.j PO; lévothyroxine : 0,075 mg 1 f.p.j PO; glyburide : 10 mg 2 f.p.j PO; metformine : 500 mg 3 f.p.j PO; sotalol : 80 mg 2 f.p.j PO; alendronate : 70 mg PO tous les dimanches; carbonate de calcium : 500 mg 2 f.p.j PO; pantoprazole : 40 mg 1 f.p.j PO; gabapentine : 600 mg 3 f.p.j PO; multivitamine i : 1 dose 1 f.p.j PO; lorazépam : 1 mg PO au coucher.

Le D^r Huang a décrit cette polypharmacie et ses conséquences comme un effet involontaire de l’approche prescriptive simple, qui consiste à identifier les troubles médicaux d’un patient et à prescrire un traitement médicamenteux classique. Cependant, les modifications des propriétés pharmacocinétiques et pharmacodynamiques des médicaments chez les personnes âgées et les multiples comorbidités observées chez ces personnes compliquent fréquemment cette approche (Figure 1).

Autres difficultés
Le D^r Huang a fait remarquer que les autres difficultés proviennent des données pharmacogénomiques et pharmacoépidémiologiques. Il a ensuite attiré l’attention des auditeurs sur les problèmes supplémentaires des maladies liées aux médicaments (en raison des interactions médicamenteuses et des interactions entre un médicament et une maladie) et sur les défis associés à la gestion de l’information depuis qu’on prescrit plus de médicaments aux personnes âgées. Il a rappelé à son auditoire que les coûts des médicaments représentent maintenant la portion la plus importante des frais de soins de santé, devant les dépenses liées à l’hospitalisation.

Le D^r Huang a détaillé les résultats d’une étude réalisée au Québec en 1990, dont l’objectif était de faire toute la lumière sur les pratiques en matière de prescription aux personnes âgées. À cette époque, le régime provincial d’assurance-maladie couvrait la totalité des dépenses en médicaments. Les chercheurs ont trouvé que le nombre de profils de prescription à haut risque (médicaments ayant une longue demi-vie, comme les benzodiazépines, ou associations médicamenteuses dangereuses, comme la combinaison d’une dose élevée d’acide acétylsalicylique et de la warfarine) augmentait avec le nombre de médecins prescripteurs et de pharmacies délivrant les médicaments. Une autre étude a montré que lorsque la province du Québec mit en place un régime d’assurance-médicaments à frais partagés, non seulement la consommation de médicaments par les personnes âgées diminua, mais cette diminution affecta parfois les médicaments essentiels, malheureusement.

Enfin, les conséquences de ces profils problématiques de prescription médicamenteuse et de consommation et d’observance du traitement de la part du patient sont davantage amplifiées du fait que les personnes âgées représentent, par définition, une population hétérogène. L’âge en tant que tel ne permet pas de déterminer correctement les conséquences des décisions pharmacothérapeutiques. En raison de tous ces facteurs, le D^r Huang a expliqué que l’optimisation de la prescription médicamenteuse aux personnes âgées représente une tâche difficile.

Optimisation du traitement médicamenteux
Le D^r Huang a noté que les médecins font face à d’autres défis dans l’exercice de leur fonction, étant souvent inondés de messages publicitaires pour de nouveaux médicaments, certains d’entre eux n’étant que des copies de médicaments existants. Nombre de ces médicaments n’ont pas été étudiés spécifiquement chez les personnes âgées, en particulier dans un contexte de polypharmacie et de comorbidités médicales multiples.

Le D^r Huang a décrit le phénomène de cascade médicamenteuse, un phénomène très important où les effets secondaires d’un médicament peuvent être interprétés de façon erronée comme une nouvelle maladie. L’ajout d’un nouveau médicament pour régler la situation (au lieu d’arrêter le médicament impliqué) peut entraîner une cascade de résultats en matière de maladies liées aux médicaments, comme dans le cas de la patiente de 85 ans présenté au début de cet article. Le D^r Huang conseille l’auditoire d’éviter les pièges liés à la prescription, en se référant à ce qu’il a intitulé les « outils pour une prescription sécuritaire » (Tableau 1).

Recommandations et conclusions
Selon le D^r Huang, il est possible d’optimiser le traitement médicamenteux pour les personnes âgées, malgré les défis décrits dans cet article. Les médecins peuvent revoir la liste des médicaments et arrêter ceux qui ne sont plus nécessaires en continu ou ceux dont le délai avant bénéfice excède l’espérance de vie du patient. Il est également utile de revoir régulièrement la liste des médicaments (en particulier lors des transitions dans les soins, comme le congé de l’hôpital), de surveiller la consommation d’alcool, de choisir des médicaments d’une même classe, mais appartenant à une autre « génération » (probablement associés à d’autres voies métaboliques) et d’utiliser des logiciels utilitaires pour dépister les interactions médicamenteuses. Il a également conseillé à l’auditoire d’éviter les médicaments ayant un indice thérapeutique limité lorsque de meilleures options existent, de s’attacher à utiliser la dose efficace la plus petite possible, et d’intégrer un plan de suivi rigoureux lorsqu’il est impossible d’éviter les interactions médicamenteuses potentielles.

Puisque tout ceci peut s’avérer un défi pour les médecins surchargés de travail, il serait bon d’envisager de partager le travail avec les autres professionnels de l’équipe de soins de santé. Par exemple, les infirmières, les physiothérapeutes et les diététistes peuvent aider à surveiller les effets indésirables médicamenteux se manifestant chez le patient sous forme de symptômes, d’hygiène orale, d’état nutritionnel, de santé et de condition physique globale et de capacité à assurer les acti-vités de la vie quotidienne. Le pharmacien joue un rôle tout aussi important, en évaluant les effets indésirables des médicaments et en offrant de la documentation sur ces effets, en suggérant des médicaments moins susceptibles d’entraîner des interactions médicamenteuses, et en éduquant le patient et la personne soignante - et peut-être les professionnels paramédicaux - sur les interactions médicamenteuses, notamment lorsqu’il s’agit d’interactions avec des suppléments, des vitamines et l’alcool.

Il est tout à fait possible de concerter les efforts et de coordonner l’action des membres de l’équipe de santé du patient, et d’optimiser un traitement médicamenteux maintenant la bonne santé et permettant à la personne âgée de fonctionner.

Message du président et introduction

Le 28^e congrès scientifique annuel de la Société canadienne de gériatrie s’est tenu du 10 au 12 avril 2008 à l’hôtel Delta centre-ville de Montréal.

Le D^r José Morais, du service de médecine gériatrique et du Centre de nutrition et des sciences de l’alimentation de McGill de l’Université McGill, membre de la Société canadienne de gériatrie (SCG) et participant, a lancé la cérémonie d’ouverture en présentant le D^r Christopher Frank, président de la SCG.

Message du président
Le D^r Frank a remercié les membres et les organisateurs de la Société, ainsi que les divers membres des sociétés internationales qui se sont déplacés à Montréal pour le congrès. Le D^r Frank a fait remarquer que le succès du congrès croît chaque année, ce qui indique que les professionnels de la santé du monde entier s’occupent d’une population qui vieillit. Cependant, comme leurs confrères canadiens, ils se retrouvent face à des défis liés à des allocations des ressources toujours plus minces.

En repensant à sa première année en tant que président de la SCG, le D^r Frank a cité les avantages associés à la petite taille de la Société, qui compte une centaine de membres : une société de petite taille est dans une position unique pour faire des percées et favoriser les contacts entre les professionnels de la santé qui se passionnent pour les soins aux personnes âgées. Cependant, puisque l’union fait la force, le meilleur moyen d’atteindre les objectifs de la Société, à savoir de promouvoir l’excellence des soins médicaux pour les personnes âgées au Canada, est de s’associer et de travailler avec d’autres groupes et d’autres sociétés, a suggéré le D^r Frank. Il a salué la présence et la participation de la Canadian Gerontological Nursing Association (Association canadienne des infirmiers et infirmières en gérontologie), de l’initiative nationale pour le soin des personnes âgées et du comité des soins aux personnes âgées.

Enfin, le D^r Frank a émis l’espoir que le congrès représente une occasion de partager des informations et des ressources entre professionnels et de renforcer les liens professionnels de la Société, pour que tous puissent se faire entendre d’une seule voix et que leurs efforts pour améliorer les soins aux personnes âgées, de concert avec les éta-blissements et les gouvernements, soient potentialisés. Le D^r Frank a terminé en appelant les participants à mettre leur savoir au service d’une contribution en tant « qu’ambassadeurs de soins » pour les personnes âgées.

Introduction et discours de bienvenue
Le D^r Howard Bergman, ancien président et membre du comité d’adhésion, a introduit le congrès en tant que tel. Le D^r Bergman a parlé des grands progrès de la Société, qui d’exclusive est devenue une Société incluant des médecins de famille, des neurologues, des infirmières et d’autres professionnels de la santé. Les 90 résumés reçus pour ce congrès (le double du congrès précédent) témoignent de la croissance de la Société, a déclaré le D^r Bergman. Il a également parlé de la croissance du journal de la Société canadienne de gériatrie. Le D^r Bergman a terminé son discours en remerciant les membres du comité du congrès, ainsi que les personnes et les organisations qui se sont occupées de la coordination et de la gestion du congrès.

Whole-body Protein Metabolism with Normal and Frail Aging

Speaker: Dr. José A. Morais, MD, FRCPC, Division of Geriatric Medicine & McGill Nutrition and Food Science Centre, McGill University, Montreal, QC.

Aging is associated with changes that may affect body protein metabolism. Dr. José Morais reviewed protein metabolism with respect to studies comparing older and younger adults.

Loss of muscle and its function is the definition of sarcopenia. At any given moment, the amount of muscle mass depends on rates of protein synthesis and breakdown. A mismatch promotes a gain or loss in lean body composition.
The basic physiological facts of protein metabolism show that protein is vital to cells both for their structure and function. There is no storage form for protein; it is in a continuous dynamic process of synthesis or breakdown. In this turnover process, there are obligatory losses of nitrogen, the basic element of amino acids (the building blocks of protein). Thus, food must compensate nitrogen loss and especially provide the essential amino acids that the body cannot synthesize (Figure 1).

Dose-responses normally exist, meaning that protein intake vs. body protein balance depends on energy intake and quality of protein (reflecting the amount of essential amino acids). The quality of the protein and the amount of intake required are also interdependent.

However, these relationships change during the life cycle. This subject is poorly understood, especially in disease states.

Model of Protein Kinetics
There are ways of measuring the turnover of proteins (protein kinetics) using stable isotope methods. A hypothetical pool of amino acids is in equilibrium with the larger pool of body proteins. Amino acids enter this pool from food intake or protein breakdown from the body, and leave the pool for protein synthesis, or are degraded. The degraded component can be captured in expired air.

In healthy, independent older adults, BMI may be in a normal range (23-25 BMI) but with age, the body shows increased adiposity and decreased lean tissue. Previous studies of protein kinetics show that older persons have lower protein turnover than younger people per kg of body weight. However, Dr. Morais’s observations showed that rates of protein turnover are unchanged with aging when expressed per kg of lean body mass, but this does not preclude changes at the muscle level.

To assess the effect of age on protein turnover rates in the whole body, Dr. Morais and colleagues compared total body MRI scans of young and older subjects, and examined scans of the mid-thigh and abdomen.¹ Results showed that the amount of fat infiltration was much greater in the older group, particularly for those with midabdominal adiposity.

In a subgroup of patients tested, they found less lean tissue and muscle in the older subjects. Twenty-four-hour urine excretions were performed to measure muscle protein breakdown—estimated from 3-methylhistidine—as an index of muscle catabolism. Results showed that muscle’s contribution to whole-body protein catabolism was significantly reduced in older persons (25.8% vs. 38.4%; P < 0.001). All measurements were adjusted for lean body mass (LBM).
Dr. Morais concluded that the lower rates of protein kinetics per kg of body weight in older adults are due to lean tissue loss. Further, he found a reduced muscle contribution to whole-body protein catabolism in older persons, due to lower muscle mass and slower fractional catabolism. Older adults’ muscles are less active and experience further health and strength decrements due to dietary protein restrictions. Further, he emphasized that protein is needed in stress states (at a higher intake than recommended) to rebound from conditions such as infection and trauma.

Dr. Morais observed that some emerging data are discordant. A study by Short K et al. on postabsorptive whole-body protein kinetics compared a program of aerobic exercise to a resistance program in terms of its effect on body composition.² Results of this study showed that aging is associated with a significant decline in protein turnover and a progressive decline in the body's remodeling processes. However, exercise was associated with increased muscle protein synthesis and performance, irrespective of age. Mixed muscle protein synthesis increased 22% (p <0.05) for older and younger test subjects.

Frailty
In his research on older adults, Dr. Morais observed that significant muscle atrophy is associated with frailty. A study of whole-body protein kinetics and muscle protein breakdown compared 8 frail versus 8 healthy older women subjected to an isoenergetic, isonitrogenous diet for 9 days.³ At the end of the diet period, they tested the effects of protein supplementation in frail subjects raised to match protein intake of the healthy group without a concomitant increase in energy.

The protein-enriched diet resulted in an increase in net endogenous protein balance and a positive nitrogen balance at the end of the diet period.

Dr. Morais stated that the higher muscle protein catabolism associated with frailty may represent an accommodation mechanism through which muscle provides amino acids to maintain visceral mass and function, essential for survival, at the expense of muscle mass. In the study, frail women maintained the capacity to retain nitrogen when given higher protein intakes. Such a diet could convey health benefits if sustained long enough to result in lean tissue accretion.

Insulin Sensitivity and Aging
Dr. Morais addressed protein metabolism resistance. Protein synthesis is regulated by insulin (which has its own receptor in muscle cells): in the fasting state, it reduces rates of protein breakdown, while in the postprandial state, it stimulates protein synthesis as long as there is enough substrate for synthesis. A deficiency or resistance to insulin’s action leads to a negative net protein balance, protein loss, and sarcopenia.

However, evidence that age is associated with insulin resistance is discordant. A study that examined the relationship between insulin action and aging using hyperglycemic clamp experiments⁴ found that age per se is not a significant cause of insulin resistance. In the whole study group, insulin action declined slightly with age but when adjusted for BMI this relationship was no longer statistically significant. A significant BMI-adjusted decrease in insulin action with age was present only in lean (BMI <25 kg/m²) women, in whom percentage fat mass also increased with age (by 0.38% body weight per decade; p = 0.0007).

Other studies support the hypothesis that an age-associated decline in mitochondrial function contributes to insulin resistance in older adults. Dr. Morais discussed a study by Petersen KF et al. that matched young and older subjects for body composition, and tried to eliminate the adiposity factor.⁵ The researchers found that aging was associated with accumulation of fat in muscle and liver tissues due to a decline of mitochondrial function and altered oxidative and phosphorylative activity.

Muscle Protein Anabolism and the Effects of Insulin
A study by Volpi et al. that measured muscle protein synthesis, breakdown, and amino acid transport found that muscle protein anabolism was stimulated by oral amino acids and glucose in older and younger subjects, though the latter increased their rates of protein retention higher than the older comparators.⁶ Dr. Morais attributed such a benefit in the young to the effects of insulin.

Dr. Morais and colleagues tested the hypothesis that hyperinsulinemia stimulates protein synthesis when postabsorptive plasma amino acid (AA) concentrations are maintained.⁷ Subjects were healthy younger and older adults (all older adults had good ADLs and all age groups had a BMI of 22-26 and a nitrogen balance). Infusion rates of glucose were higher in younger versus older participants. Younger participants also had higher rates of protein turnover and synthesis measurements. Protein breakdown was equally supressed in both groups.
Both reduction in absolute fat-free mass and increased adiposity are associated with an altered anabolic action of insulin. Therefore, adiposity is more important to insulin resistance than age alone, and the whole-body anabolic response to hyperinsulinemia decreased with aging, and in women vs. men. This blunted response in older subjects was mediated by insulin’s failure to stimulate protein synthesis. Since amino acids are able to stimulate protein synthesis, older adults might benefit from an increased dietary protein intake to compensate for the insulin resistance of aging.

Conclusion
Dr. Morais concluded that sarcopenia is due in part to aging. Mitochondrial DNA damage leads to decreased function and energy production, and to a reduced capacity of muscle protein synthesis. If mitochondrial function is decreased, energy cannot be used normally and will accumulate, leading to muscle fat infiltration, a recognized cause of insulin resistance. The decrease in muscle protein synthesis itself will lead to sarcopenia, but is aggravated by malnutrition.

Once sarcopenia is present, there is less energy expenditure, which leads to adiposity, and ultimately insulin resistance. The latter can also be exacerbated by inactivity. These factors contribute to a metabolic explanation of sarcopenia of aging.

References

1. Morais JA, Ross R, Gougeon R, et al. Distribution of protein turnover changes with age in humans as assessed by whole-body magnetic resonance image analysis to quantify tissue volumes. J Nutr 2000;130:784-91.
2. Short KR, Vittone JL, Bigelow ML, et al. Age and aerobic exercise training effects on whole body and muscle protein metabolism Am J Physiol Endocrinol Metab 2004;286:E92-101.
3. Chevalier S, Gougeon R, Nayar K, et al. Frailty amplifies the effects of aging on protein metabolism: role of protein intake. Am J Clin Nutr 2003;78:422-9.
4. Ferrannini E, Vichi S, Beck-Nielsen H, et al. Insulin action and age. Diabetes 1996;45:947-53.
5. Petersen KF, Befroy D, Dufour S, et al. Mitochondrial dysfunction in the elderly: possible role in insulin resistance. Science 2003;300:1140-2.
6. Volpi E, Mittendorfer B, Wolf SE, et al. Oral amino acids stimulate muscle protein anabolism in the elderly despite higher first-pass splanchnic extraction. Am J Physiol 1999;277(3 Pt 1):E513-20.
7. Chevalier S, Gougeon R, Choong N, et al. Influence of adiposity in the blunted whole-body protein anabolic response to insulin with aging. J Gerontol A Biol Sci Med Sci 2006;61:156-64.

Frailty: Searching for a Relevant Clinical and Research Paradigm

Speaker: Howard Bergman, MD, The Dr. Joseph Kaufmann Professor and Director Division of Geriatric Medicine, McGill University, Montreal, QC; Co-Director: Solidage Research Group, Montreal, QC; Director, Quebec Research Network in Ageing/Fonds de Recherche en Santé du Québec, Montreal, QC; Chair, Advisory Board, Institute of Aging, Canadian Institutes of Health Research, Ottawa, ON.

The term frailty, observed Dr. Howard Bergman, is widely used by health professionals who treat aging adults. Nonetheless, the concept remains ill-defined. What is it, what are its components, and how is it measured in the clinical setting? Does the term add something to the effort to mitigate adverse health outcomes among older adults?

Conceptualizing Frailty and Understanding the Aging Process
The challenge of studying frailty, Dr. Bergman maintained, is the lack of clear criteria to designate it. How frailty differs from disability, and how researchers and clinicians define effects of aging versus markers of frailty are areas of evolving medical knowledge. The result is that clinicians are utilizing the concept without agreement on its meaning, a problem exacerbated by the fact that frailty is a nonmedical term circulating in popular language.
The 2nd International Working Meeting on Frailty and Aging held in Montreal in March of 2006 sought to address key issues and controversies related to the concept of frailty. The core features agreed upon are presented in Table 1. Participants concurred that frailty is “an increased vulnerability to stressors due to impairments in multiple, inter-related physiologic systems.” These impairments are believed to lead to declining homeostatic reserve and resiliency. The working group acknowledged that while frailty and disability have overlap, they remain distinct concepts (Figure 1). A key feature of frailty is that it is associated with increased risk of morbidity and mortality, stated Dr. Bergman.

Frailty has been described with various combinations of components including physiological abnormalities, impairments in physical, cognitive, and/or psychological function, and other features such as advanced age.
According to Dr. Bergman, research strategies that use the life-course approach can significantly contribute to the current understanding of frailty. This individualized, integrative approach conceives that how one ages is a product of factors across the whole life span—including environmental exposures, genetic predispositions, and health behaviours. Critical factors across the life course may determine whether one ages healthfully or not. This research and clinical approach attempts to elucidate the heterogeneity of functional decline in older people.

Ongoing Controversies in Defining and Using the Frailty Concept
Frailty is not yet a clinical instrument. Controversies and grey areas that persist include disentangling chronic disease states from frailty. Dr. Bergman described the two as bearing a complex relationship: there is some overlap, but the key distinction is that while most frail persons have chronic disease, most people with chronic disease are not frail. There is a distinct increase in the prevalence of frailty when the number and severity of chronic diseases increase. Whether frailty is a secondary condition rather than an underlying state is still being explored. Further, being frail and having a high index of comorbidities are not equivalent. It is important to consider contextual issues in health care—for example, studies suggest that patients with poor access to health care will show higher degrees of frailty.
Dr. Bergman highlighted that there is a spectrum of frailty models. At one extreme of the spectrum frailty is represented as a medical syndrome and at the other it is a group of risk factors (Table 2).

In viewing frailty as a syndrome with defining core features, Dr. Bergman suggested that there may be important lessons to be learned from the metabolic syndrome. As with frailty, there is debate and controversy about the clinical definition of the metabolic syndrome. As syndromes, the presence of multiple components are expected have a stronger association with adverse outcomes than the sum of the individual components.

Dr. Bergman acknowledged the disadvantages associated with increasing utilization of the frailty concept. For example, physicians may overvalue the symptom cluster, thereby overlooking the possible value of a single symptom. In addition, some of the measures proposed for frailty such as gait velocity or grip strength do not have established cut-offs, thereby making it difficult to determine how to classify individuals. Further, introducing “frailty” as a diagnosis in clinical practice carries the potential danger of inappropriate labeling, which can have various negative effects on a patient’s health state and health-related decision-making.

However, Dr. Bergman stated, the concept of frailty also holds great potential value for physicians, as it has functional utility in clinical practice. The term identifies a subset of vulnerable older adults at high risk of adverse outcomes. The health needs of older persons who are functionally independent, with apparently normal cognitive function, may be overlooked if clinicians disregard identifiable frailty markers.

Frailty markers provide health care planners with the ability to make valuable predictions, according to Dr. Bergman. A wider clinical application of the concept could improve understanding of the aging process and enhance clinicians’ ability to characterise the heterogeneity in the health of older persons. With an aging population, the capacity to better target and remediate risk in nondisabled older adults with chronic disease could lead to better tailoring of health interventions, and correspondingly, improved health outcomes. For example, Dr. Bergman cited a study that found that patient care measures that delayed the onset of disability and/or dependence by only 1 or 2 years reduced needs for long-term care and institutional resources significantly.

Conclusions and Recommendations
Dr. Bergman concluded that while research and debate on frailty has improved understanding of aging adults, the concept retains at present more potential than practical and acknowledged utility. Ultimately the test of frailty’s relevance will lie in further research initiatives on frailty and whether medical professionals succeed in improving health promotion, prevention, treatment, rehabilitation, and care interventions for aging adults.

Optimizing Prescribing among Older Adults

Speaker: Dr. Allen R. Huang, MDCM, FRCPC, FACP, Associate Professor of Medicine, McGill University; Director, Division of Geriatric Medicine, McGill University Health Centre, Montreal, QC.

Dr. Allen Huang focused on the distinct problems encountered when prescribing medications to older adults.

Why Prescribing for Older Adults Is Complex
He underlined how difficult basic prescribing can become in what he called “a typical case”:
An 85-year-old woman is brought to the ER by her concerned spouse. She is suffering confusion, nausea and vomiting, and is quite thin—presenting with a syndrome often labeled as “general deterioration.” Her husband reports her condition has recently worsened, that she needs more of his help to manage her activities of daily living, and that her alertness varies during the day. The patient’s medical conditions include: diabetes, hypothyroidism, hypertension, congestive heart failure, atrial fibrillation, previous stroke, and a 2-decade history of polymyositis. Examination reveals a BP of 110/70 and a slowed pulse of 40 beats/minute. Significant abnormal lab tests included: INR=8.3, serum digoxin level 3.24 nmol/l, TSH=0.24, and a creatinine clearance of 21 ml/min.

Her current medication list showed 13 agents: warfarin 2.5mg PO qD; digoxin 0.25mg PO qD; hydrochlorothiazide 50mg PO qD; levothyroxine 0.075mg PO qD; glyburide 10mg PO bid; metformin 500mg PO tid; sotalol 80mg PO bid; alendronate 70mg PO qSunday; calcium carbonate 500mg PO bid; pantoprazole 40mg PO qD; gabapentin 600 mg PO tid; multivitamin i PO qD; and lorazepam 1 mg PO qHS.

Dr. Huang described this degree of polypharmacy and its consequences as an unintended effect of the straightforward prescription approach, which involves identifying a patient`s medical conditions, and then using standard drug therapy. However, altered pharmacokinetics and pharmacodynamics, and the multiple comorbidities commonly present in older adults frequently complicate this approach (Figure 1).

Additional Complexities
Additional complexities, Dr. Huang noted, come from pharmacogenomics and pharmacoepidemiologic data. He then drew listeners’ attention to additional problems of drug-related illness (involving drug-drug and drug-disease interactions), and the challenging task of information management since more drugs are dispensed to the older adult population. He reminded those in attendance that drug costs now account for the greatest proportion of health care costs, over hospitalization-related expenses.

Dr. Huang detailed the results of a 1990 study in Quebec that sought to clarify prescribing practices for the older patient segment. At that time, full drug cost coverage was offered under the provincial health plan. Researchers found that high-risk prescribing patterns (drugs such as long half-life benzodiazepines or risky combinations such as high-dose acetylsalicylic acid plus warfarin) increased with the number of prescribing physicians and dispensing pharmacies involved. Another study found that when the province of Quebec implemented a cost-sharing drug plan, the consumption of medications by older people decreased, and distressingly, sometimes with essential medications.
Finally, the consequences of these problematic patterns of drug prescribing, patient consumption, and treatment adherence are further complicated by the fact that older adults are a fundamentally non-homogeneous population. Age alone is a poor determination of the consequences of pharmacotherapeutic decisions. Given these factors, Dr. Huang described the capacity of the physician to optimize prescribing in older adults as a difficult task.

Optimizing Drug Therapy
Dr. Huang noted further challenges facing physicians in a practice environment where they are frequently bombarded with the marketing of new drugs, some of which are merely “me-too” drugs. Many of these new drugs have often not been studied specifically in the older patient population, especially in the setting of polypharmacy and multiple medical comorbidities.

Dr. Huang described the important phenomenon of the medication cascade, where side effects of one drug can be misinterpreted as a new condition. Adding a new prescription (instead of stopping the offending medication) to solve this situation can lead to a cascade that results in drug-related illnesses, as in the case of the 85-year-old woman described. Dr. Huang advised listeners to avoid prescription pitfalls by referring to “The Safe Prescribing Toolbox” (Table 1).

Recommendations and Conclusions
According to Dr. Huang, it is possible to optimize drug therapy for the older patient population, despite the challenges described above. Physicians can review and stop drugs that no longer have an indication for ongoing use, or that are associated with a time-to-benefit exceeding an individual patient’s life expectancy. Other helpful actions include reviewing medication regularly (especially at care transitions such as hospital discharge), monitoring for alcohol use, selecting drugs from different “generations” within a class (which are likely to involve different metabolic pathways), and screening for drug interactions using software tools. He further advised that listeners try to avoid drugs with a narrow therapeutic index when better alternatives exist, work to attain a lowest-effective dose, and integrate a close monitoring plan when a potential drug–drug interaction cannot be avoided.

Because the foregoing can be a challenge for busy clinicians, the work can be shared with other professionals on the health care team. Nurses, physiotherapists, and dieticians, for example, can help monitor drug side effects as reflected in patients’ symptoms, oral hygiene, nutritional status, overall health and fitness, and capacity to carry out activities of daily living. The pharmacist’s role is equally important in offering assessments and documentation of any adverse drug events, suggesting drugs with lower risks of interactions, educating the patient and caregiver—and perhaps allied health professionals—on drug interactions, especially when it comes to interactions with health supplements, vitamins, and alcohol.

With concerted effort and coordinated action among members of a patient’s health care team, optimized drug therapy that maintains good health and function in older adults is an attainable goal.

Presidential Address and Introduction

The Canadian Geriatrics Society’s 28th Annual Scientific Meeting was held at the Hotel Delta Centre-Ville, in Montreal, from April 10-12, 2008.

Dr. José Morais, of the Division of Geriatric Medicine & McGill Nutrition and Food Science Centre at McGill University, and Canadian Geriatrics Society (CGS) member and meeting presenter, commenced the opening ceremony by introducing CGS president Dr. Christopher Frank.

Presidential Address
Dr. Frank expressed appreciation for the Society’s members and organizers, and acknowledged the numerous members of international societies who had travelled to Montreal for the meeting. Dr. Frank noted the expansion of the annual meeting year to year as indicating that health professionals worldwide are working with an increasingly aging population but are challenged by the ever tighter resource allocation that Canadian health professionals experience as well.

Reflecting on his first year as CGS president, Dr. Frank cited the advantages of the society’s intimate population of a few hundred members: a small society is uniquely positioned to make inroads and connect with health care professionals who are passionate about care for aging adults. However, noting the adage of strength lying in numbers, the best way to achieve the Society’s aim of promoting excellence in the medical care of older Canadians, he suggested, is to ally and work with other groups and societies. He acknowledged the presence and involvement of the Canadian Gerontological Nursing Association; the National Initiative for the Care of the Elderly; and the Health Care of the Elderly Committee.

Finally, Dr. Frank expressed his hope that the meeting would offer the chance for professionals to share information and resources as well as to solidify the Society’s professional bonds, so that they might “speak with one voice rather than several” and thereby potentiate their efforts as they work within institutions and with governments to improve elder care. Dr. Frank closed his remarks with an appeal to attendees that they use their knowledge toward becoming “ambassadors of care” for aging adults.

Introduction and Welcoming Remarks
Past CGS president and Membership Committee co-chair Dr. Howard Bergman provided an introduction to the meeting itself. Dr. Bergman observed the notable strides the society had made, stating its initial exclusivity had given way to a marked inclusivity encompassing the participation of family physicians, neurologists, nurses, and other health professionals. A testament to the development of the society, Dr. Bergman cited, were the ~90 abstracts received (a doubling from the previous meeting). In addition to the Society’s growth, he acknowledged the growth of the Canadian Geriatrics Society Journal. Dr. Bergman closed his remarks with thanks to the meeting’s committee members and the individuals and organization who coordinated and managed the meeting.

I am always pleased when we focus on renal disease among older adults, because for the past few years I have been heavily involved in the administration of a dialysis rehabilitation program for older patients at the Toronto Rehabilitation Institute. The program has been successful primarily because of the brilliant clinical leadership of a nephrologist, Vanita Jassal, who is also well trained in geriatrics and is the co-author with Dr. Gemini Tanna of our new web exclusive feature. Kudos also have to go to Professor Dimitri Oreopoulos, one of the most renowned nephrologists in the world (and a Canadian!), who recognized the impact of the aging of the dialysis population over 20 years ago. To enter a dialysis unit in 2007 is very similar to entering a geriatric day hospital, as so many of the patients are older adults. The unit managed by Dr. Jassal is attuned to the complex medical and rehabilitation needs of older adults, and has a high success rate in getting patients back to their own homes.

Despite the success in rehabilitating older patients on dialysis, the issue of end-stage renal disease is still overwhelming. We obviously need more emphasis on instituting proper measures to slow progression of chronic kidney disease once it starts. To achieve this, doctors need to recognize early evidence of renal impairment and institute appropriate therapies. This requires the use of a classification system that is practical in day-to-day clinical practice. This is the thrust behind our web exclusive article “Chronic Kidney Disease Classification” by Drs. Gemini Tanna and Sarbjit Vanita Jassal. Another focus article is on “Disorders of Potassium Homeostasis” by Dr. Vijay Rao and Dr. Madhav Rao. Our CME article this month is on one of the commonest of renal disorders and is entitled “Metabolic Evaluation and Management of Older Adults with Kidney Stones” by Dr. Richard Norman.

We have our usual group of excellent articles on other geriatric topics. Our CVD column is on “Aortic Dissection in Older Adults” by Dr. George D. Oreopoulos, and our dementia column is entitled “Frontotemporal Dementia” by Drs. Simone Pomati, Francesca Clerici, Stefano Defendi, Silvia Bovo, and Claudio Mariani. Our Drugs & Aging column addresses the difficult topic of “Warfarin Drug Interactions among Older Adults” and is by Andrew Liu and Dr. Carmine Stumpo. Given the seriousness of the problem, I am particularly pleased to see that this month’s Gastrointestinal Disease column offers “A Rational Approach to Constipation” and is by Dr. Shawna Silver, Dr. Hershl Berman, and Laura Brooks. Our Cancer column on “Distress--the Sixth Vital Sign in Cancer Care” is by Drs. Barry D. Bultz, Bejoy C. Thomas, Douglas A. Stewart, and Linda E. Carlson. And last, our Preventative Care article is by a group whom I am fortunate to work with at times: “The Seniors Wellness Clinic: An Interprofessional Health Promotion and Disease Prevention Care Model” by Lina Medeiros, Debbie Kwan, Carol Banez, Beatrise Poroger-Edelstein, Kitty Mak, Keegan K. Barker, and Rory Agellon.

Finally, it’s my pleasure to announce that Geriatrics & Aging is now formally affiliated with the Canadian Society for the Study of the Aging Male (CSSAM). As an association of physicians and health care professionals collaborating on research and public awareness initiatives about the full spectrum of changes that aging men experience, CSSAM and our journal share an educational mission. We are Canada’s leading medical publication dealing with issues specific to an aging population, and we too work to disseminate information on all conditions that affect the health of this growing population segment. We are confident that this alliance will promote greater awareness and understanding of the health of men as they age, and we are excited about the potential of this partnership to contribute to physician education and improvement of care.

Enjoy this month’s journal.

Barry Goldlist