Constant incidence rates of needle-stick injury paradoxically suggest modest preventive effect of sharps disposal system

Does placement of impenetrable sharps disposal systems in hospitals reduce needle-stick injury? To study this question, annual health questionnaires were distributed on a quarterly basis to all 8000 employees in an academic medical center in a large eastern US metropolitan city asking each employee whether he or she had experienced a needle-stick injury since the last questionnaire. Questionnaires from active floor nurses were separated and hand tallied in 1987, 1989, and 1990, the latter 2 years being after impenetrable sharps disposal systems had been placed at nursing stations and in individual patient rooms. Total needle sticks in staff nurses reported during the 3 years (20.5%, 23.2%, 21.8%, not significant) did not decrease in the last 2 years. Simultaneously, hospital purchases of needle-containing devices increased 13.5%. Thus a constant reported needle-stick incidence rate may paradoxically represent a modest preventive effect of a hospital sharps-disposal system.