Duration of Antibiotic Use Among Adults With Uncomplicated Community-Acquired Pneumonia Requiring Hospitalization in the United States

Abstract

Background: Previous studies suggest that duration of antibiotic therapy for community-acquired pneumonia (CAP) often exceeds national recommendations and might represent an important opportunity to improve antibiotic stewardship nationally. Our objective was to determine the average length of antibiotic therapy (LOT) for patients treated for uncomplicated CAP in US hospitals and the proportion of patients with excessive durations.

Methods: Records of retrospective cohorts of patients aged 18-64 years with private insurance and aged ≥65 years with Medicare hospitalized for CAP in 2012-2013 were used. Inpatient LOT was estimated as a function of length of stay. Outpatient LOT was based on prescriptions filled post discharge based on data from outpatient pharmacy files. Excessive duration was defined as outpatient LOT >3 days.

Results: Inclusion criteria were met for 22128 patients aged 18-64 years across 2100 hospitals and 130746 patients aged ≥65 years across 3227 hospitals. Median total LOT was 9.5 days. LOT exceeded recommended duration for 74% of patients aged 18-64 years and 71% of patients aged ≥65 years. Patients aged 18-64 years had a median (quartile 1-quartile 3) 6 (3-7) days outpatient LOT and those aged ≥65 years had 5 (3-7) days.

Conclusions: In this nationwide sample of patients hospitalized for CAP, median total LOT was just under 10 days, with more than 70% of patients having likely excessive treatment duration. Better adherence to recommended CAP therapy duration by improving prescribing at hospital discharge may be an important target for antibiotic stewardship programs.

Figure 1.

Prediction model of inpatient length of therapy in adults hospitalized for community-acquired pneumonia. Data were obtained from the MarketScan Hospital Drug Database. Restricted to patients receiving ≥1 inpatient antibiotic plus restriction criteria listed in the Methods section. Using linear regression, inpatient length of therapy (LOT) was modeled as a function of length of stay (LOS) as follows: LOT = β₁LOS_2days + β₂LOS_3days + β₃LOS_4days + β₄LOS_5days + β₅LOS_6days + β₆LOS_7days + β₇LOS_8days + β₈LOS_9days + β₉LOS_{10 days}. R² values: 18–64 years, 0.78; 65+ years, 0.73.

Figure 2.

Flow diagram of eligibility and inclusion of adults hospitalized for community-acquired pneumonia. ^aReasons for exclusion are not mutually exclusive. ^bIn accordance with the Centers for Medicare & Medicaid Services data use agreement and for consistency in presentation, actual number and corresponding percent of total were not displayed when cell sizes ≤10. ^cOutpatient antibiotic prescription filled within −1 to +3 days of discharge from index hospitalization. Abbreviations: d/c, discharge; HIV, human immunodeficiency virus; LOS, length of stay; LOT, length of therapy; NA, not available; PN, pneumonia.

Figure 3.

Total length of antibiotic therapy of adults hospitalized for community-acquired pneumonia.

Figure 4.

Antibiotic selection by setting and demographic among adults hospitalized for community-acquired pneumonia. Inpatient antibiotic class selection data were ranked by days of therapy. Outpatient antibiotic class selection was ranked at the prescription level. Antibiotics from separate classes that may have been used in combination therapy are treated independently. Percent selection for a given antibiotic class was calculated as follows: inpatient setting: number of days of therapy for given antibiotic class/total number of days of therapy and outpatient setting: number of prescriptions for a given antibiotic class/total number of prescriptions. β-lactam combinations refers only to β-lactam/β-lactamase combinations. Abbreviation: gen, generation.