EXCLUSION OF ELDERLY SUBJECTS FROM CLINICAL-TRIALS FOR PARKINSON-DISEASE

Objectives: To determine whether subjects older than 75 years are incl uded in the randomized controlled trials of antiparkinsonian medicatio ns conducted during the last 30 years and to identify study characteri stics that are associated with the exclusion of patients of advanced a ge. Methods: A systematic search was conducted on MEDLINE from January 1966 until September 1996 of all randomized controlled trials of drug s used to treat the motor symptoms of Parkinson disease. Articles were abstracted for the age of subjects, date of publication, geographic l ocation, drug class studied, stage of Parkinson disease of subjects, a nd the number of subjects in each trial. Results: One hundred twelve a rticles met the inclusion criteria. The weighted mean (+/-SD) age for subjects in all trials was 62.2+/-3.9 years. Forty-two studies (37.5%) included subjects older than 75 years. However, in 31 articles (27.7% ) it could not be determined if subjects older than 75 years were incl uded. Among the 8 studies that provided the actual number of subjects within specific age groups, only 8 (5.5%) of 145 subjects were older t han 75 years. Publication in the last decade was significantly associa ted with a decreased likelihood of including subjects older than 75 ye ars (odds ratio, 0.19; 95% confidence interval, 0.06-0.62). Conclusion s: The relatively small number of subjects older than 75 years include d in controlled trials of anti-parkinsonian drugs seriously impedes ou r understanding of the efficacy and safety of these drugs in a large s ubgroup of frail patients for whom these products are prescribed. The tendency to exclude subjects of advanced age is highest in the most re cently published articles that study new advances in pharmacotherapy. There is inadequate reporting of the age characteristics of subjects i n clinical trials. This limitation hinders the synthesis of data regar ding drug efficacy and toxicity relevant to older age groups.