Factors associated with increased risk of exacerbation and hospital admission in a cohort of ambulatory COPD patients: A multiple logistic regressionanalysis

Background and Objective: The aim of this study was to develop and validate two models to estimate the probabilities of frequent exacerbations (more t han 1 per year) and admissions for chronic obstructive pulmonary disease (C OPD) that can be used in a primary care setting. Methods: Information was o btained in a cross-sectional observational study on ambulatory COPD patient s performed in 201 general practices located throughout Spain. The model fo r admissions included 713 cases, 499 for the developmental sample and 214 i n the validation sample; the model for frequent exacerbations included 896 patients, 627 in the developmental sample and 269 in the validation model. Candidate variables to be included in both models were: age, sex, body mass index (BMI), FEV1 as percent predicted [FEV1 (% pred.)], active smoking, c hronic mucus hypersecretion (CMH) and significant comorbidity. Results:The admission model contained 2 readily obtainable variables: comorbidity (OR = 1.97; CI 95% = 1.24-3.14) and FEV1(% pred.) (OR = 0.72; 0.58-0.88, for eve ry 10 units), and well calibrated in developmental and validation samples ( goodness-of-fit tests: p = 0.989 and p = 0.720, respectively). The model fo r frequent exacerbations included 3 variables: age (OR = 1.21; 1.01-1.44; f or every 10 years of increasing age), FEV1 (% pred.) (OR = 0.82; 0.70-0.96, for every 10 units) and CMH (OR = 1.54; 1.11-2.14) and also well call cali brated (p = 0.411 and p = 0.340 in the developmental and validation samples , respectively). Conclusions: Our results suggest that FEV1 impairment expl ains part of the risk of frequent exacerbations and hospital admissions. Fu rthermore, CMH and increasing age are significantly associated with the ris k of frequent exacerbations, but severity of exacerbations provoking hospit al admissions is associated with the presence of significant comorbidity. T hese important and easily measurable variables contain valuable information for optimal management of ambulatory patients with COPD. Copyright (C) 200 0 S. Karger AG, Basel.