Factors Related with Hospital Attendance and Mortality in Patients with COPD: A Case-Control Study in a Real-Life Setting

Introduction: The rising trend in hospital admissions among patients with chronic obstructive pulmonary disease (COPD) is worrying, not only because of the increasing costs, but also because of the worsening quality of life. We aimed to identify the predictive factors of hospital admission, re-admission and mortality of COPD patients through using information exclusively registered in electronic clinical records. Methods: We conducted a population-based case-control study. All data were sourced from the different information systems comprising the Galician Health Service electronic record database. We included in the study patients diagnosed with COPD (code R95 in the medical record), >= 35 years old and with at least one spirometry performed =3 years prior inclusion. We fitted three logistic regression models, each one to ascertain the factors that influence the probability of admission, re-admission, and mortality, and calculated odds ratios (OR) with their 95% confidence intervals (95% CI). Results: COPD patients were admitted due to respiratory causes a mean of 1.51 times across the period December 2016-December 2017, with 55% requiring re-admission in the next 90 days. The factor most closely associated with the re-admission profile was home oxygen therapy (OR 3.06 95% CI 2.42-3.87), followed by male gender (OR 2.01 95% CI 1.48-2.72), a CHA2DVASc scale score >2 (OR 1.28 95% CI 1.16-1.42), and severity by clinical risk group stratification (OR 1.14 95% CI 1.04-1.26). Male sex (OR 1.47 CI 95% 1.04-2.09), having been readmitted =2 times (OR 1.34 CI 95% 1.11-1.61) and being =70 years old (OR 1.05 CI 95% 1.03-1.08) increase the probability of dying from COPD during the study period. Conclusion: These results confirm the complexity of management of COPD exacerbations, and indicate the need to establish strategies that would ensure continuity of care after hospital admission, with the aim of preventing re-admissions and death.