Impact of socioeconomic status and lifestyle factors on incidence of COPD and hospital readmissions: 13.7-year follow-up in UK Biobank

Socioeconomic status and lifestyle conferred an impact on the incidence or first re-admission of chronic obstructive pulmonary disease (COPD), but the impact on recurrent re-admissions for COPD remains unclear. We aimed to simultaneously study their impacts on first hospital admission and re-admissions for COPD in a large prospective cohort study. We included 439,463 participants without COPD at baseline from the UK Biobank and identified subsequent COPD-related admissions through linkage with national hospital databases, defined by International Classification of Diseases codes (ICD-9: 491, 492, 496; ICD-10: J40–J44). We adopted the Prentice, Williams and Peterson calendar time model to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) of first admission and re-admissions for COPD associated with socioeconomic status and lifestyle factors (e.g., smoking, healthy diet, and physical activity). Subgroup analyses were further conducted by age, gender, and ethnicity. During a median follow-up of 13.7 years, 13,291 (3.02%) participants were hospitalized for COPD, among whom 6,980 (52.52%) were re-admitted with a median number of two hospital re-admissions per person. The risk of COPD re-admissions is elevated with the increasing number of cumulative admissions. Higher Townsend deprivation index, smoking, unhealthy diet, and lower physical activity were associated with a significantly increased risk of both first admission and re-admissions. The HRs of first admission and re-admissions were 1.08 (95%CI, 1.07–1.08) and 1.01 (95%CI, 1.01–1.02) per unit increase in Townsend deprivation index, respectively. Compared with non-smokers, both current smokers and ex-smokers had higher risks of first admission and re-admissions. Moderate- and vigorous-intensity physical activity was associated with decreased risks of admissions. Moreover, these associations were significantly modified by age, gender, and ethnicity. Socioeconomic status and lifestyle factors are independent modifiable factors of first admission and multiple re-admissions for COPD. The findings provide important evidence to guide the management of patients with COPD to prevent or delay hospital admission for exacerbations.