Intern Emerg Med. 2021 Jan 16. doi: 10.1007/s11739-020-02618-3. Online ahead of print.
Lower respiratory tract infections (LRTIs) due to bacterial pneumonia are common among hospitalized patients and are frequently treated with antibiotics. Viral illnesses and exacerbations of heart failure or COPD may present with symptoms mimicking a LRTI, resulting in unnecessary antibiotic utilization. Procalcitonin testing may be useful in these clinical scenarios. We attempted to assess the utility of procalcitonin testing versus not testing, and positive versus negative results among hospitalized patients with suspected LRTI. We performed a retrospective cohort study using multivariable analysis comparing clinical outcomes of patients with and without procalcitonin testing. Patients were 18 years or older, hospitalized for pneumonia, heart failure, COPD, or a viral respiratory illness between October 2014 and October 2015 (n = 2353). All patients received at least one dose of antibiotics. Major outcomes were duration of antibiotic therapy, length of hospital stay, C. difficile testing and infections, and normalized total direct costs. Procalcitonin testing occurred in 14.0% of patients and pneumonia (70.6%) was the most common diagnosis. After covariate adjustments, mean length of stay (5.61 vs. 6.67 days, p < 0.001) and duration of antibiotics (3.95 vs. 4.47 days, p < 0.001) were shorter among tested patients. Fewer 30-day readmissions (OR 0.62, 95% CI 0.40-0.95) were observed, and total direct healthcare costs were 34% lower (0.66, 95% CI 0.58-0.74) among tested patients. Negative procalcitonin results were associated with further reductions in some outcomes. In conclusion, procalcitonin testing among hospitalized patients with suspected LRTI is associated with reductions in antibiotic duration, length of stay, 30-day readmission, and healthcare costs.