Procalcitonin testing has the potential to reduce unnecessary antibiotic use in patients with suspected lower respiratory tract infections

Abstract

Lower respiratory tract infections are often treated with antibiotics without evidence of clinically relevant bacterial disease. Serum calcitonin precursor concentrations, including procalcitonin, are raised in bacterial infections, but not in viral infections. Hypothesis Procalcitonin (PCT)-guided treatment of suspected lower respiratory tract infection substantially reduces antibiotic use without compromising clinical or laboratory outcomes. Methods Design: Prospective, cluster-randomized, controlled, singleblinded intervention trial. Setting: Medical emergency department of a 784-bed academic tertiary care hospital in Basel, Switzerland. Subjects: 243 patients presenting to the emergency department who were admitted with suspected lower respiratory tract infection as the main diagnosis. Intervention: Patients were randomly assigned to either standard care (n=199) or PCT-guided treatment (n=124). In the latter group, serum PCT concentrations were used to advise clinicians. Use of antibiotics was: strongly discouraged (PCT <0.1 μg/L), discouraged (≥0.1 and <0.25 μg/L), advised (≥0.25 and <0.5 μg/L), or strongly advised (≥0.5 μg/L). Re-evaluation was possible after 6-24 hours in both groups. Outcomes: The primary endpoint was antibiotic use with analysis by intent to treat. Secondary endpoints included clinical and laboratory outcomes. Results Final diagnoses were pneumonia (36%), acute exacerbation of chronic obstructive pulmonary disease (25%), acute bronchitis (24%), asthma (5%), and other respiratory affections (10%). Serological evidence of viral infection was recorded in 141 of 175 tested patients (81%). Bacterial cultures were positive from sputum in 51 (21%) and from blood in 16 (7%). In the procalcitonin group, the adjusted relative risk of antibiotic exposure was 0.49 (95% CI 0.44- 0.55; p<0.0001) compared with the standard group. Antibiotic use was significantly reduced in all diagnostic subgroups. Clinical and laboratory outcomes were similar in both groups. Conclusion PCT-guided therapy of suspected lower respiratory tract infection substantially reduced antibiotic use without compromising clinical or laboratory outcomes.