Diabetes and the Risk of Acute Urinary Tract Infection Among Postmenopausal Women

Abstract

OBJECTIVE—To examine whether the presence of diabetes alters the risk of acute urinary tract infection (UTI) in postmenopausal women. RESEARCH DESIGN AND METHODS—A case-control study of the Group Health Cooperative of Puget Sound (GHC), a staff-model nonprofit health maintenance organization in Washington State, was conducted. Subjects were women aged 55–75 years who had been members of GHC for at least 1 year and who had had an acute symptomatic UTI within the preceding month. Laboratory files were used to identify women with a urine culture that grew ≥105 colonies of a urinary pathogen. Medical records were reviewed to confirm the presence of acute, clinically symptomatic UTI. Control subjects were randomly selected from the GHC enrollment file, screened to remove women with recent UTI, and frequency matched to cases by age within 2 years. An interviewer ascertained self-reported clinician-diagnosed diabetes. Diagnosis of diabetes was confirmed by the GHC diabetes registry. A subsample of women underwent measurement of postvoid residual bladder volume (n = 748) and culture of vaginal flora (n = 454). RESULTS—Of the 901 case and 913 control subjects, diabetes was reported in 13.1 and 6.8%, respectively. The health plan diabetes registry confirmed the diagnosis in 92% of women who self-reported the condition. The age-adjusted odds ratio (OR) for UTI in relation to self-reported clinician-diagnosed diabetes was 2.2 (95% CI 1.6–3.0). Adjustment for frequency of sexual intercourse and history of UTI had little effect on this estimate. Compared with nondiabetic women, higher UTI odds were seen in subjects who used oral hypoglycemic agents (OR 2.9 [95% CI 1.7–5.1]) and insulin (2.6 [1.5–4.6]) but not in subjects with untreated diabetes or diabetes treated by lifestyle changes (1.3 [0.7–2.3]). No significant difference was seen in the OR for UTI in diabetic women with disease of shorter duration (<10 years, OR 1.9) or longer duration (≥10 years, OR 2.6) or in relation to HbA1c level. Similar microbiologic pathogens were seen in diabetic and nondiabetic women. No significant differences were seen by diabetes status in mean postvoid residual bladder volume or vaginal flora. CONCLUSIONS—Diabetes under pharmacologic treatment is associated with increased risk of clinically apparent UTI in postmenopausal women.