Background: Asymptomatic bacteriuria is common among women with diabetes, and the treatment of such infections has been recommended to prevent complications related to symptomatic urinary tract infection. Methods: We enrolled women (>16 years of age) with diabetes, bacteriuria (greater/equal 10(sup 5) colony-forming units of an organism per milliliter in cultures of two consecutive urine specimens), and no urinary symptoms; 50 were randomly assigned to receive placebo and 55 to receive antimicrobial therapy. For the first six weeks, which included the initial course of treatment, the study was placebo-controlled and double-blind. Subsequently, the women were screened for bacteriuria every three months for up to three years; antimicrobial therapy was provided to women in the antimicrobial-therapy group who had asymptomatic bacteriuria. Results: Four weeks after the end of the initial course of therapy, 78 percent of placebo recipients had bacteriuria, as compared with 20 percent of women who received antimicrobial agents (P<0.001). During a mean follow-up of 27 months, 20 of 50 women in the placebo group (40 percent) and 23 of 55 women in the antimicrobial-therapy group (42 percent) had at least one episode of symptomatic urinary tract infection. The time to a first symptomatic episode was similar in the placebo group and the antimicrobial-therapy group (P=0.67 by the log-rank test), as were the (+/-SD) rates of any symptomatic urinary tract infection (1.10+/-0.17 and 0.93+/-0.14 per 1000 days of follow-up, respectively; relative risk, 1.19; 95 percent confidence interval, 0.28 to 1.81), pyelonephritis (0.28+/-0.08 and 0.13+/-0.05 per 1000 days of follow-up; relative risk, 2.13; 95 percent confidence interval, 0.81 to 5.62), and hospitalization for urinary tract infection (0.10+/-0.36 and 0.06+/-0.22 per 1000 days of follow-up; relative risk, 1.93; 95 percent confidence interval, 0.47 to 7.89). The women in the antimicrobial-therapy group had almost five times as many days of antibiotic use for urinary tract infection as did the women in the placebo group (158.2+/-1.7 vs. 33.7+/-0.91 per 1000 days of follow-up; relative risk, 0.21; 95 percent confidence interval, 0.20 to 0.22). Conclusions: Treatment of asymptomatic bacteriuria in women with diabetes does not appear to reduce complications. Diabetes itself should not be an indication for screening for or treatment of asymptomatic bacteriuria.
