GLASGOW—Antibiotics may be a useful adjunctive treatment for overactive bladder (OAB), according to British researchers.

About 50% of patients presenting with OAB appear to have an infection or an inflammatory process at the heart of their OAB etiology, despite presenting with negative routine urinalyses, they noted.

A team led by James Malone-Lee, MD, Professor of Medicine at University College London, studied 440 OAB patients (380 women and 60 men) whom they divided into three groups. Group 1 (147 patients) had OAB and pyuria and were treated with antibiotics in addition to antimuscarinics and bladder retaining. Group 2 (212 patients) had OAB without pyuria and were treated only with antimuscarinics and bladder retraining. Group 3 (81 patients) had OAB but manifested late pyuria at subsequent follow-up, at which time antibiotics were initiated.

Group 3 patients took significantly longer to recover (198-321 days) compared with group 1 (165-229 days). The late introduction of antibiotics was followed by significant symptom improvement. Group 2 patients recovered the fastest (138-180 days). The three groups, each treated differently based on clinical presentation, improved similarly, the researchers noted in a poster presentation.

“Important circumstantial evidence of antibiotic efficacy was demonstrated by clearance of pyuria in group 1,” the authors stated, adding that the effects of introducing antibiotics late into group 3, followed by strong evidence of a response, favors efficacy.  “Infection as a significant disease complication is implied by the shorter time-course of treatment in group 2.”

The researchers pointed to a previous study (J Urol 2010;183:1843-1847) demonstrating that the microscopic non-dipstick detection is the best surrogate marker of urinary infection available, superior to dipsticks and routine mid-stream urinary specimen culture. “This raised the implication that patients, with OAB symptoms but manifesting microscopic pyuria, despite negative urine cultures, should be treated with antibiotics as an adjunct to antimuscarinics and bladder retraining,” Dr. Malone-Lee’s group stated.

They concluded that their findings provide strong justification for a large-scale randomized, placebo-controlled trial of antibiotic use in patients with OAB and pyuria but a negative urine culture.