Single-Dose Antibiotic Therapy for Urinary Tract Infections and Type II Error-Reply

—Ms Jordan seems to take issue with our conclusion that single-dose trimethoprim-sulfamethoxazole treatment of uncomplicated urinary tract infections in women is less effective than the conventional multiple-dose therapy. We agree that, from the results of our analysis, the cure rate for single-dose therapy at 87% appears to be quite similar to the cure rate of 90% for multiple-dose therapy. We agree that even if the difference in these two rates were statistically significant, the clinician would probably perceive it to be clinically insignificant. However, our conclusion that single-dose therapy with trimethoprim-sulfamethoxazole is likely to be less effective than multiple-dose therapy is based on the real possibility of a type II error from our analysis (95% confidence interval, with single-dose therapy of 78% to 92% and with multiple-dose therapy of 81% to 95%). We also based this conclusion on the report of the well-done randomized trial by Schultz et al¹