External validation of the COmorbidity test

Abstract

The COmorbidity TEst (COTE) is a Chronic Obstructive Pulmonary Disease (COPD)-specific co-morbidity score created to predict mortality. Before its wide application at the University of New Mexico we intended to validate it. The study was conducted at the University of New Mexico Hospital (UNMH) in Albuquerque, NM, USA, a tertiary academic hospital. Consecutive patients with the clinical diagnosis of COPD were identified using the hospital's medical records system and included if they were older than 40 years, had smoked at least 20 pack-years and their post bronchodilator forced expiratory volume in the first second/forced vital capacity (FEV1/FVC) was <0.7 without an alternative diagnosis. The data collected included demographics, co-morbidities as described in the COTE, COPD-specific therapies, spirometry results and mortality. Of 317 patients 51.4% were male, average age was 65.6 ± 9.6 years and the mean post-bronchodilator FEV1 percent predicted (FEV1%) was 52.9 ± 16.9%. 31 (9.8%) patients were on triple long-acting bronchodilator inhaler therapy, 88 (27.8%) on two long-acting bronchodilators and 163 (51.4%) on at least one long-acting bronchodilator. The median follow-up was 3.5 years (IQR = 1.9–6.9). Fifty four patients died by the end of the follow-up period and their median COTE of 4 (IQR = 1–8) was significantly higher than for the survivors with COTE = 1 (IQR = 0–6; p = 0.002). In univariable analyses COTE was positively associated while FEV1%, body mass index (BMI) and gender were negatively associated with all-cause mortality. In multivariable analysis BMI, FEV1% and COTE remained independent predictors for mortality. The COTE is an independent predictor of mortality for COPD patients at UNMH.