Objective: To determine whether an excess incidence of dermatomyositis or polymyositis or both exist in patients treated with injectable bovine collagen implants and to characterize the clinical picture.
Design: Historical cohort study (July 1980 through June 1988).
Patients: Patients were identified from personal experience or adverse reaction reports received by the manufacturer.
Setting: An 8-year period in the United States during which approximately 345 000 patients received implants.
Results: Eight patients with dermatomyositis and an additional patient with polymyositis were identified from approximately 345 000 patients receiving injectable bovine collagen implants from July 1980 through June 1988. The nine patients with dermatomyositis or polymyositis were diagnosed an average of 6.4 months (range, 0.7 to 24.9 months) after collagen implant or skin test exposure or both. Eight of the nine patients had a delayed-type hypersensitivity response at the test or treatment sites or both, and five of six patients tested were found to have increased serum antibodies to collagen. Compared with the general population, the incidence of dermatomyositis or polymyositis among collagen-treated patients was statistically increased (standardized incidence ratio, 5.05; 95% CI, 2.31 to 9.59; P < 0.0001). A similar analysis of the eight dermatomyositis case patients produced a standardized incidence ratio of 18.8 (CI, 8.1 to 37.0; P < 0.0001).
Using a Monte Carlo simulation, an interval of 6.4 months or less from exposure to onset of disease was found to be an extremely rare event, occurring less than 72 times per one million simulation trials (CI, 57 to 91).
Conclusions: Because these data suggest that an immunologic response to bovine type I or type III collagen or both caused this dermatomyositis or polymyositis-like syndrome, the risks versus benefits for the cosmetic use of collagen implants should be reassessed.