[Procalcitonin-guided antibiotic use vs. a standard approach for acute respiratory tract infection in primary care].

BACKGROUND Acute respiratory tract infections are the most common reason for antibiotic therapy in primary care despite their mainly viral etiology. A laboratory test measuring procalcitonin levels in blood specimens was suggested as a tool to reduce unnecessary prescribing of antibiotics. We consider whether antibiotic therapy guided by procalcitonin reduces the use of antibiotics without increasing the restrictions experienced by patients by more than 1 day. METHODS Fifty-three primary care physicians recruited 458 patients, each patient with an acute respiratory tract infection and, in the physician's opinion, in need of antibiotics. Patients were centrally randomized to either a procalcitonin-guided approach to antibiotic therapy or to a standard approach. For patients randomized to procalcitonin-guided therapy, the use of antibiotics was more or less strongly discouraged (procalcitonin level, < or =0.1 or < or =0.25 microg/L, respectively) or recommended (procalcitonin level, >0.25 microg/L). Follow-up data were collected at 7 days by treating physicians and at 14 and 28 days by blinded interviewers. RESULTS Adjusted for baseline characteristics, the mean increase at 14 days in days in which activities were restricted was 0.14 with procalcitonin-guided therapy (95% confidence interval [CI], -0.53 to 0.81 days), which met our criterion of an increase in days in which activities were restricted by no more than 1 day. With procalcitonin-guided therapy, the antibiotic prescription rate was 72% lower (95% CI, 66%-78%) than with standard therapy. Both approaches led to a similar proportion of patients reporting symptoms of ongoing or relapsing infection at 28 days (adjusted odds ratio, 1.0 [95% CI, 0.7-1.5]). CONCLUSIONS As an adjunct to guidelines, procalcitonin-guided therapy markedly reduces antibiotic use for acute respiratory tract infections in primary care without compromising patient outcome. In practice, this could be achieved with 1 to 2 procalcitonin measurements in patients for whom the physician intends to prescribe antibiotics.