RISK ASSESSMENT OF POLYMYOSITIS DERMATOMYOSITIS AFTER TREATMENT WITH INJECTABLE BOVINE COLLAGEN IMPLANTS

Background: Questions have been raised about a possible relation betwe en injectable collagen and polymyositis and dermatomyositis (PM/DM). P redictions of the prevalence of PM/DM have been based on anecdotal est imates of the duration of fellow-up for the collagen-treated populatio n. Objective: Our purpose was to study the duration of follow-up for a large sample of collagen-treated patients. Methods: Physicians in Nor th America who purchased collagen implants during fiscal year 1988 wer e categorized according to collagen practice size; one third were rand omly invited to participate in the study. Results: Review of 2622 pati ent records yielded an average duration of follow-up of 4 years. Concl usion: Five-year incidence rates were used to estimate the expected nu mber of cases of PM/DM in the collagen-treated population. Through Jun e 1993 the expected number was 30.2, The number of confirmed cases aft er treatment was seven, less than one fourth of the number of cases ex pected for a model of the collagen-heated population, matched for age, sex, and race.