Association between diaphragm use and urinary tract infection
S. D. Fihn, R. H. Latham, P. Roberts, K. Running and W. E. Stamm
We conducted independent case-control and retrospective cohort
investigations to assess the relationship between diaphragm use and urinary
tract infection (UTI). In the former, we compared diaphragm use and vaginal
flora among 114 women with acute UTI and 85 women with acute urinary tract
symptoms and no UTI. In the latter study, we ascertained the incidence of
UTI in 192 diaphragm users and 182 women taking oral contraceptives during
a mean follow-up of 9.4 months. Both studies demonstrated a significantly
increased risk of UTI in diaphragm users: relative odds were 2.0 in the
case-control study and the relative risk was 2.5 in the retrospective
cohort study. Vaginal colonization with Escherichia coli was significantly
greater in diaphragm users. The incidence of UTI in the cohort study was
26.6 per 1,000 patient-months for diaphragm users and 8.9 per 1,000
patient-months for women taking oral contraceptives. The increased risk of
UTI in diaphragm users could not be attributed to differences in age,
parity, sexual activity, or previous UTI.
