Education
Education
CMAJ 1997;156(3):385-91.
[résumé]
This article has been peer reviewed.
Paper reprints may be obtained from: Dr. Peter J. McLeod, Montreal General Hospital, Department of Medicine, B2 1181650 Cedar Ave., Montreal QC H3G 1A4; fax 514 934-8267
© 1997 Canadian Medical Association (text and abstract/résumé)
Design: Mail survey of a 32-member national panel.
Setting: Academic medical centres across Canada.
Participants: Thirty-two specialists selected arbitrarily, including 7 clinical pharmacologists, 9 geriatricians, 8 family practitioners and 8 pharmacists.
Outcome measures: Consensus that the practice would introduce a substantial and significant increase in the risk of a serious adverse effect and is common enough that its curtailment would decrease morbidity among elderly people, ranking of clinical importance of the risk, and availability of equally or more effective and less risky alternative therapy.
Results: The 32-member national panel developed a list of 71 practices in prescribing for elderly people and rated the clinical significance of each on a scale of 1 (not significant) to 4 (highly significant). The practices in prescribing identified fell into 3 categories: drugs generally contraindicated for elderly people, drugdisease interactions and drugdrug interactions. The mean significance rating was greater than 3 for 39 practices. For each practice, alternative therapies were recommended. There was surprising congruence among the specialists on the significance rating and the suggested alternative therapies.
Conclusion: The authors have developed a valid, relevant list of inappropriate practices in prescribing for elderly people, to be used in a practice-based intervention study.
Conception : Sondage postal auprès d'un panel national de 32 membres.
Contexte : Centres médicaux d'enseignement du Canada.
Participants : Trente-deux spécialistes choisis arbitrairement, dont 7 pharmacologistes cliniques, 9 gériatres, 8 médecins de famille et 8 pharmaciens.
Mesures des résultats : Consensus selon lequel la pratique entraînerait une augmentation importante et significative du risque d'effets indésirables graves et est assez répandue pour que son confinement réduise la morbidité chez les personnes âgées, classement de l'importance clinique du risque et disponibilité d'un traitement de substitution aussi ou plus efficace et moins risqué.
Résultats : Le panel régional de 32 membres a dressé une liste de 71 pratiques d'établissement d'ordonnances pour les personnes âgées et coté l'importance clinique de chacune sur une échelle de 1 (aucune importance) à 4 (grande importance). Les pratiques d'établissement d'ordonnances ont été réparties en 3 catégories : médicaments en général contre-indiqués pour les personnes âgées, interactions entre médicaments et maladies et entre médicaments. La cote de signification moyenne a été supérieure à 3 dans le cas de 39 pratiques. Dans chaque cas, on a recommandé des thérapies de substitution. La cote d'importance et les thérapies de substitution recommandées ont fait l'objet d'un consensus étonnant chez les spécialistes.
Conclusion : Les auteurs ont établi une liste valide et pertinente de pratiques indues d'établissement d'ordonnances pour les personnes âgées. Cette liste servira dans le contexte d'une étude d'intervention fondée sur la pratique.
We believe that inappropriate prescribing is a preventable cause of morbidity and mortality. We have therefore started a study to determine whether a computer-based intervention that allows practitioners to conduct surveillance of patient prescriptions, coupled with expert assistance with prescribing decisions, will reduce inappropriate and questionable prescribing. The intervention project will be based on a credible, validated list of high-risk practices in prescribing for elderly people. The most widely used set of explicit criteria for inappropriate prescribing for elderly people was developed by Beers and collaborators.[12] These criteria have been used in other studies,[1316] but we found them unacceptable for our purposes. Specifically, we disagreed with the authors' designation of some of the drugs as inappropriate for prescription for elderly people. Among these drugs were reserpine and chlorthalidone, both valuable antihypertensive agents,[17,18] chlorpropamide, a useful orally administered hypoglycemic agent,[19] and amitriptyline, a useful agent for a broad range of pain syndromes.[20] Some of the drugs listed by Beers and collaborators, such as isoxsuprine, cyclandelate and propoxyphene, have fallen into disuse and therefore do not merit inclusion.
Our clinical experience suggests that drugdrug and drugdisease interactions should be significantly emphasized in any discussion of inappropriate prescribing for elderly people. We therefore developed a new list of inappropriate practices for our intervention project. This article describes the development of the list. We used a modified Delphi approach to arrive at consensus recommendations of a national expert panel.
[Table of contents]
Methods
Development of a preliminary list
We initially categorized inappropriate practices in prescription of drugs for elderly people into 3 types: (1) prescription of drugs generally contraindicated for elderly people because of an unacceptable riskbenefit ratio, (2) prescription of drugs that can cause drugdrug interactions and (3) prescription of drugs that can cause drugdisease interactions. For the first category we used the list developed by Beers and collaborators[12] as a model, and we excluded drugs not available in Canada and drugs for which we were unable to find supporting evidence of significant risk. A preliminary list of drugdrug interactions was developed from a quarterly expert review of drug interactions[21] and the Medical Letter Handbook of Adverse Drug Interactions.[22] From these references, a review panel of 6 specialists with academic affiliations independently selected the drugdrug interactions to be included in the preliminary list sent to the national consensus panel. The list of inappropriate practices involving drugdisease interactions was developed by one of us (A.R.H.), an experienced academic geriatrician, from standard textbooks on therapy provided to elderly people. All of the authors reviewed the drugs in all 3 categories before mailing the list to the members of the national consensus panel.
Criteria for judgements by members of the national consensus panel
Having developed the 3 categories of inappropriate prescribing, we elaborated on the criteria to be used by the national consensus panel to define important inappropriate prescribing practices. We decided to include only practices that met 3 criteria: (1) the prescription introduces a substantial and clinically significant increase in the risk of a serious adverse effect, (2) equally effective or more effective and less risky alternative therapy is available for most patients, and (3) the practice is likely to occur often enough that a change in practice could decrease morbidity in elderly people.
Selection of an expert panel
In selecting the national consensus panel, we aimed for a reasonable balance among geographic regions of Canada and among relevant specialties. We arbitrarily chose a panel of 32 specialists representing clinical pharmacology, geriatrics, family medicine and pharmacy. We identified experts in each discipline and contacted them by telephone to solicit their participation. All of the specialists selected were sent a letter in early August 1995 outlining the purpose of the study, the criteria for making judgements about prescribing practices and the process we planned to follow in developing the list.
Evaluation of the preliminary list
In late August 1995 we sent the panel members the preliminary list of 38 important, inappropriate practices, which included 16 practices involving generally contraindicated drugs, 11 involving drugdrug interactions and 11 involving drugdisease interactions. To facilitate evaluation, each practice was depicted in a brief clinical situation. We asked the experts to assess the preliminary list, to suggest additions in each of the 3 categories and to recommend relevant lower-risk alternative therapies. The responses from the consensus panel members were used to supplement and revise the preliminary list, creating the final list.
Rating of the clinical importance of each practice on the final list
The final, revised list of practices was mailed to panel members, who were asked to rate the clinical importance of the potential adverse effects of each practice on a 4-point scale from 1 (not significant) to 4 (highly significant). Panel members were also asked to indicate their agreement or disagreement with the alternative therapy suggested for each practice.
Overall mean clinical significance ratings were calculated for each practice from the ratings by all of the panel members. Mean ratings by specialty were calculated by combining the ratings by the panel members in each of the 4 specialties represented. We performed an analysis of variance of these mean significance ratings to compare the ratings among specialties.
[Table of contents]
Results
The national consensus panel consisted of 32 specialists: 7 clinical pharmacologists, 9 geriatricians, 8 family practitioners and 8 pharmacists. All responded promptly to the first mailing of the preliminary list of 38 inappropriate practices in prescribing, and the respondents suggested a total of 51 additions to the list. There was modest overlap in the suggestions. Most panel members contributed recommendations for alternative therapy.
The final list mailed to panel members consisted of 71 practices in prescribing for elderly people. Each was depicted in a clinical situation, and each situation was accompanied by a recommendation for alternative therapy. All of the panel members returned the final lists, giving their clinical significance ratings and indicating their agreement or disagreement with the alternative therapy suggested.
The mean clinical significance rating varied from a low of 2.53, for adding cholestyramine to the regimen of a patient who was already taking digoxin to treat atrial fibrillation, to a high of 3.83, for prescribing a ß-adrenergic blocking agent to treat hypertension for patients with a history of asthma or chronic obstructive pulmonary disease. The proportion of panel members who agreed with recommendations for alternative therapies in the high-risk prescribing practices varied modestly. The lowest level of agreement (25% of members) was for the use of procainamide as an alternative to disopyramide in the treatment of atrial fibrillation. For many practices, such as substitution of acetaminophen for a nonsteroidal anti-inflammatory drug (NSAID) to treat osteoarthritis, there was 100% agreement.
Analysis of the responses by specialty showed no significant differences in the mean clinical significance ratings of the 71 practices, although there was a higher mean significance rating (3.16) by geriatricians and a lower mean significance rating (2.96) by clinical pharmacologists. Family practitioners' and pharmacists' mean ratings fell between those of geriatricians and clinical pharmacologists.
Table 1, Table 2, Table 3 and Table 4 rank the 38 prescribing practices that received a mean clinical significance rating of 3.0 or greater from panel members. The inappropriate prescribing practices have been grouped into 4 categories: prescription of drugs to treat cardiovascular diseases, prescription of psychotropic drugs, prescription of NSAIDs and other analgesics and prescription of miscellaneous drugs. Eighteen of the 38 practices involve drugs generally contraindicated for elderly people because of an unacceptable riskbenefit ratio. Sixteen involve a drugdisease interaction, and only 4 involve drugdrug interactions. Three of these 4 concern interactions with the orally administered anticoagulant warfarin.
Almost all of the panel members wrote unsolicited comments about the overall list and about the high-risk practices. Most of the comments were aimed at enhancing the specificity of the criteria. Examples include: "Resist any push to put chlorpropamide and reserpine on the list"; "There are data indicating benefit of ß-blockers in heart failure"; "Thiazides are OK in non-insulin-dependent diabetes [mellitus] if used in low doses"; "All H2 blockers can interact with warfarin"; and "Recommendations for alternatives are semi-controversial. Perhaps brevity is the problem."
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Discussion
We have described a relatively new approach to defining inappropriate practices in prescribing for elderly people. Our approach takes into account the clinical relevance of the prescribing practice and the opportunities to have a beneficial effect on the problem it creates. We assured that the recommendations would be generalizable by involving specialists in clinical pharmacology, geriatrics, family medicine and pharmacy, the 4 types of specialists most commonly involved in the management of drugs given to elderly people. The broad geographic representation of panel members assured that local or regional prescribing practices[13] did not overly influence the development of the list. There was surprising congruence among the specialists in the 4 disciplines on the clinical importance of each of the practices listed. Therefore, even if our list has missed some important inappropriate practices, we are confident that those listed are regarded as important by a large, diverse group of disinterested specialists.
The high-risk prescribing situations in our final list represent mainly drugs generally contraindicated for elderly people plus risky drugdisease interactions. Drugdrug interactions are less prominent. In this way, our list differs significantly from one recently proposed by Willcox, Himmelstein and Woolhandler.[13] Their list included mainly contraindicated drugs. Our list takes into account the fact that diseases that alter drug metabolism or elimination or tissue sensitivity to therapeutic agents must be accounted for when weighing prescribing risk. Furthermore, our consensus panel did not identify methyldopa, propranolol or chlorpropamide as contraindicated drugs for elderly people, as did Willcox, Himmelstein and Woolhandler. Centrally acting drugs such as benzodiazepines, tricyclic antidepressants and selective serotonin reuptake inhibitors are prominent in our final list. These drugs are especially relevant to prescribing for elderly people, who are often intolerant of centrally acting drugs but who continue to account for a disproportionately large share of their use.[23]
This list of inappropriate practices in prescribing is now undergoing final modifications before it is used in a double-blind, controlled trial of a computer-based intervention aimed at improving prescribing for elderly people. We anticipate that we will have to revise the list regularly if it is to be helpful to practising physicians. For many drugs prescribed for elderly people there is a dearth of evidence-based guidelines, so we will rely on a consensus panel for revisions. We hope that the criteria developed in this study will be considered for use by clinicians caring for older people, researchers in geriatric pharmacotherapy and teachers of undergraduate and postgraduate students.
This research was carried out by members of the Quebec Research Group on Medication Use in the Elderly (Groupe de recherche du Québec sur l'utilisation des médicaments chez les personnes âgées, USAGE) and was financially supported by the Health Canada Seniors Independence Research Program and by the Fonds de la recherche en santé du Québec.
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References