Population-based analysis of patients with COPD in Catalonia: a cohort study with implications for clinical management

BACKGROUND: Clinical management of patients with chronic obstructive pulmonary disease (COPD) shows potential for improvement provided that patients’ heterogeneities are better understood. The study addresses the impact of comorbidities and its role in health risk assessment. OBJECTIVE: To explore the potential of health registry information to enhance clinical risk assessment and stratification. DESIGN: Fixed cohort study including all registered patients with COPD in Catalonia (Spain) (7.5 million citizens) at 31 December 2014 with 1-year (2015) follow-up. METHODS: A total of 264 830 patients with COPD diagnosis, based on the International Classification of Diseases (Ninth Revision) coding, were assessed. Performance of multiple logistic regression models for the six main dependent variables of the study: mortality, hospitalisations (patients with one or more admissions; all cases and COPD-related), multiple hospitalisations (patients with at least two admissions; all causes and COPD-related) and users with high healthcare costs. Neither clinical nor forced spirometry data were available. RESULTS: Multimorbidity, assessed with the adjusted morbidity grouper, was the covariate with the highest impact in the predictive models, which in turn showed high performance measured by the C-statistics: (1) mortality (0.83), (2 and 3) hospitalisations (all causes: 0.77; COPD-related: 0.81), (4 and 5) multiple hospitalisations (all causes: 0.80; COPD-related: 0.87) and (6) users with high healthcare costs (0.76). Fifteen per cent of individuals with highest healthcare costs to year ratio represented 59% of the overall costs of patients with COPD. CONCLUSIONS: The results stress the impact of assessing multimorbidity with the adjusted morbidity grouper on considered health indicators, which has implications for enhanced COPD staging and clinical management. TRIAL REGISTRATION NUMBER: NCT02956395.