Pharmacoeconomics of treating uncomplicated urinary tract infections.

The frequency of urinary tract infections (UTIs) and mounting pressure for cost containment in medical care emphasize the need to consider costs of evaluating and treating UTIs. Many clinicians base antibiotic choice on drug cost, probably because this information is objective and readily available. However, the cost of treating UTI patients involves other factors, such as pathogenic susceptibility and consequences of inadequately treated infection. These factors and their associated costs can be difficult to assess and weigh against issues such as drug cost. The direct cost of treating a UTI patient includes not only initial medical evaluation and treatment, but what occurs subsequently. If initial treatment is provided with a drug for which a pathogen is not sensitive, patients will be likely to continue to experience symptoms and return for re-evaluation, resulting in a more thorough evaluation and a second antibiotic, generally a more expensive fluoroquinolone. The most important predictor of high cost-effectiveness is high efficacy against the most common urinary pathogen, Escherichia coli. The lower the effectiveness of antibiotics against this pathogen, the greater the number of revisits and cases of progression to pyelonephritis. Increased follow-up care results in diminished cost-effectiveness. Antibiotic cost is a poor predictor of cost-effectiveness, illustrated by the finding that the most and least expensive drugs, ofloxacin and trimethoprim-sulfamethasoxazole, are approximately equally cost-effective. Both of these are more cost-effective than other drugs, nitrofurantoin and amoxicillin, considered in this analysis.