Physician adjudication of angioedema diagnosis codes in a population of patients with heart failure prescribed angiotensin‐converting enzyme inhibitor therapy

Purpose Our objective was to calculate the positive predictive value (PPV) of the ICD‐9 diagnosis code for angioedema when physicians adjudicate the events by electronic health record review. Our secondary objective was to evaluate the inter‐rater reliability of physician adjudication. Methods Patients from the Cardiovascular Research Network previously diagnosed with heart failure who were started on angiotensin‐converting enzyme inhibitors (ACEI) during the study period (July 1, 2006 through September 30, 2015) were included. A team of two physicians per participating site adjudicated possible events using electronic health records for all patients coded for angioedema for a total of five sites. The PPV was calculated as the number of physician‐adjudicated cases divided by all cases with the diagnosis code of angioedema (ICD‐9‐CM code 995.1) meeting the inclusion criteria. The inter‐rater reliability of physician teams, or kappa statistic, was also calculated. Results There were 38 061 adults with heart failure initiating ACEI in the study (21 489 patient‐years). Of 114 coded events that were adjudicated by physicians, 98 angioedema events were confirmed for a PPV of 86% (95% CI: 80%, 92%). The kappa statistic based on physician inter‐rater reliability was 0.65 (95% CI: 0.47, 0.82). Conclusions ICD‐9 diagnosis code of 995.1 (angioneurotic edema, not elsewhere classified) is highly predictive of angioedema in adults with heart failure exposed to ACEI.