Validation of a Community-Acquired Pneumonia Score To Improve Empiric Antibiotic Selection at an Academic Medical Center

Abstract

The 2019 American Thoracic Society and the Infectious Diseases Society of America Community-Acquired Pneumonia (CAP) Guidelines recommend drug resistant pathogens (DRP) be empirically covered if locally validated risk factors are present. This retrospective case-control validation study evaluated the performance of the Drug-Resistance in Pneumonia (DRIP) clinical prediction score. Two hundred 17 adult patients with ICD-10 pneumonia diagnosis, positive confirmed microbiologic data, and clinical signs and symptoms were included. A DRIP score of ≥ 4 was used to assess model performance. Logistic regression was used to select for significant predictors and create a modified DRIP score, which was evaluated to define clinical application. The DRIP score predicted pneumonia due to a DRP with a sensitivity of 67% and specificity of 73%. The AUROC curve was 0.76 (95% CI, 0.69-0.82). From regression analysis, prior infection with a DRP and antibiotics in the last 60 days, yielding score of 2 and 1 points respectively, remained local risk factors in predicting drug-resistant pneumonia. Sensitivity (47%) and specificity (94%) were maximized at a threshold of ≥ 2 in the modified DRIP model. Therefore, prior infection with a DRP remained the only clinically relevant predictor for drug-resistant pneumonia. The original DRIP score demonstrates a decreased performance in our patient population and behaves similar to other clinical prediction models. Empiric CAP therapy without anti-MRSA and anti-pseudomonal coverage should be considered for non-critically ill patients without a drug resistant pathogen infection in the past year. Our data support the necessity of local validation to authenticate clinical risk predictors for drug-resistant pneumonia.

Derivation and Validation of a Clinical Prediction Score to Identify the Isolation of Pseudomonas in Pneumonia

“…By weighing this risk factor with a score of 14, patients growing Pseudomonas aeruginosa on any culture within 6 months prior to admission would automatically be identified as a case and would already pass the threshold of >11. This is similar to previous models and publications, which found that prior infection with a DRP on any culture within 1 year of admission was a risk factor for drug-resistant pneumonia ( 12 , 15 ).…”

“…This is comparable to the AUROC of 0.77 in our validation cohort. Given that the previous study compared the different models derived from single institutions, the AUROC values of these models would likely be different if they were applied at our institution, as shown by others ( 15 ). In addition, the other models included DRPs collectively or MRSA and not specifically Pseudomonas aeruginosa , as was done in this analysis.…”

“…A retrospective chart review conducted at a Veterans Affairs Hospital also found that the use of the drug resistance in pneumonia (DRIP) score led to an increase in the use of broad-spectrum antimicrobials, and the authors concluded that local validation of the score is necessary prior to its implementation ( 14 ). When applied at an academic medical center, the DRIP score also demonstrated decreased performance when utilized at a site other than its derivation location ( 15 ).…”

Pneumonia: Drug-Related Problems and Hospital Readmissions

“…An additional new method for improving empirical antibiotic selection is the community-acquired pneumonia score. This score provides a model of clinical data, thereby enabling the proper use of empirical antibiotics [17]. Implementation of an empiric therapy guide is important to minimize DRPs in the initial selection of antibiotics for pneumonia, as the causative organism and the patient's susceptibility to it are often unknown at the time of prescription.…”

“…Therefore, a new method being considered for improving empirical antibiotic selection is the community-acquired pneumonia score. This score can be used in a prediction model of clinical data, enabling more accurate application of empirical antibiotics [17]. In addition, many intervention tools need to be applied, such as antibiotic management programs, biomarkers, and computerized physician order entries (CPOE), to ensure the effectiveness and safety of guideline compliance.…”