Introduction: Lower respiratory tract infections (LRTIs) are the most frequent indication for antibiotics in primary care setting. Inappropriate use of antibiotics can lead to antibiotic-resistance and increases in healthcare costs. In an attempt to improve decision-making for antibiotic use in LRTI,s a number of biomarkers have been tested to guide the decision of whether to initiate antibiotics. One of these biomarkers, procalcitonin(PCT), has been shown to be helpful at decreasing antibiotic use in patients with LRTIs without increasing morbidity/mortality. Research suggests that in certain clinical situations, when patients have a low PCT value, physicians should be strongly discouraged from prescribing antibiotics. At our institution, although PCT had been ordered frequently, we wondered if PCT results were being used to help direct antibiotic therapy. We specifically wanted to determine whether an undetectable PCT changed antibiotic management for patients admitted with LRTIs.
Methods: Using the electronic medical record, all inpatient PCTs ordered between 1/30/10 and 3/29/11 were obtained. Undetectable PCT levels, defined as <0.05 ng/mL, were included in this analysis and all other values were excluded. The charts of patients for whom an undetectable PCT was measured were reviewed and data including demographics, use of antibiotics before and after PCT measurement, and hospital diagnoses were collected. Data was analyzed using standard biostatistical measures.
Results: A total of 1142 PCT tests were ordered during the time period studied. Of those, 381 (33.3%) were reported as undetectable. Two-hundred and twenty-four (58.8%) patients were receiving antibiotics at the time PCT was drawn. A negative procalcitonin value may have contributed to 24% reduction in antibiotic use. One-hundred thirty-one (29.7%) patients in with negative PCT values had a diagnosis of pneumonia. In patients diagnosed with pneumonia, antibiotics were stopped in 27%, continued without an alternate infection in 50%, and continued with an alternative infectious diagnosis in 19%.In patients diagnosed with a COPD exacerbation, antibiotics were stopped in 40% after negative PCT level and continued or added in 60%.
Conclusions: Despite many limitations to our study, it often appeared that clinical judgment overruled lab values inpatients with suspected LRTIs in whom PT levels were odered. While PCT measurement is a simple intervention that is easy to implement into hospital practice that may reduce antibiotic exposure and associated costs, its current role is limited.