A Systematic Review of Clinical Prediction Rules for the Diagnosis of Influenza

Background: Clinical prediction rules (CPRs) can assist clinicians by focusing their clinical evaluation on the most important signs and symptoms, and if used properly can reduce the need for diagnostic testing. This study aims to perform an updated systematic review of clinical prediction rules and classification and regression tree (CART) models for the diagnosis of influenza. Methods: We searched PubMed, CINAHL, and EMBASE databases. We identified prospective studies of patients presenting with suspected influenza or respiratory infection and that reported a CPR in the form of a risk score or CART-based algorithm. Studies had to report at a minimum the percentage of patients in each risk group with influenza. Studies were evaluated for inclusion and data were extracted by reviewers working in parallel. Accuracy was summarized descriptively; where not reported by the authors the area under the receiver operating characteristic curve (AUROCC), predictive values, and likelihood ratios were calculated. Results: We identified 10 studies that presented 14 CPRs. The most commonly included predictor variables were cough, fever, chills and/or sweats, myalgias, and acute onset, all which can be ascertained by phone or telehealth visit. Most CPRs had an AUROCC between 0.7 and 0.8, indicating good discrimination. However, only 1 rule has undergone prospective external validation, with limited success. Data reporting by the original studies was in some cases inadequate to determine measures of accuracy. Conclusions: Well-designed validation studies, studies of interrater reliability between telehealth an inperson assessment, and studies using novel data mining and artificial intelligence strategies are needed to improve diagnosis of this common and important infection. (J Am Board Fam Med 2021;34:1123-1140.)