SAN DIEGO—Dutasteride use is associated with a decreased risk of urinary tract infection (UTI) and related hospitalizations resulting from transrectal prostate biopsy, researchers reported at the American Urological Association 2016 annual meeting.

Daniel M. Moreira, MD, and Mayo Clinic in Rochester, MN, and colleagues retrospectively studied the effect of dutasteride on transrectal prostate biopsy-associated UTI (TPBA-UTI) in a cohort of 6,422 men aged 50–75 years with a PSA level of 2.5–10 ng/mL. The men were participants in the REDUCE [Reduction by Dutasteride of Prostate Cancer Events] trial. They were randomly assigned to receive oral dutasteride 0.5 mg or placebo daily.

Fifty-four men (0.8%) experienced TPBA-UTI: 15 (0.5%) in the dutasteride arm and 39 (1.2%) in the placebo arm. Dutasteride use was associated with a significant 61% decreased relative risk of any TPBA-UTI compared with non-use. Results also showed that 14 patients (0.2%) had severe TPBA-UTI: 2 (0.06%) in the dutasteride arm and 12 (0.4%) in the placebo group. Dutasteride use was associated with a significant 83% decreased relative risk of severe TPBA-UTI versus non-use.

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According to the investigators, 137 patients would need to be treated with dutasteride to prevent 1 case of TPBA-UTI and 326 would need to be treated to prevent 1 case of severe TPBA-UTI.

The researchers defined TPBA-UTI as the presence of urinary symptoms and the prescription of antibiotics by the treating physician, both within 30 days after a prostate biopsy. They defined severe TPBA-UTI as a TPBA-UTI requiring hospitalization.

Dr Moreira’s group noted that previous studies have demonstrated that dutasteride decreases the risk of UTI in men with benign prostatic hyperplasia.

“The mechanisms by which dutasteride reduces urinary tract infections are not entirely understood,” Dr Moreira told Renal & Urology News. “There are several factors that may play a role.”

For example, he noted that dutasteride use is associated with a reduction in prostate size and lower post-void residual (PVR). “In our study, we adjusted our analyses for prostate size and PVR, and the results were virtually unchanged compared to unadjusted ones. This suggests that other mechanisms may be play a role in the relationship between dutasteride and lower UTI rate.”