Changing age-pattern of hospitalisation risk of chronic obstructive pulmonary disease in men and women in Canada.

OBJECTIVE To examine the changing pattern of age distributions of hospitalisation for chronic obstructive pulmonary disease (COPD) among Canadian men and women. DESIGN Retrospective cohort study. PARTICIPANTS 257,604 COPD inpatients aged 55-90 years with 463,089 hospital admissions during a 3-year study period (1994/95, 1995/96 and 1996/97) in Canada. MAIN OUTCOME MEASURES COPD listed as one of the first five underlying diagnoses (broad definition, 463,089 hospitalisations) or as first diagnosis (narrow definition, 142,770 hospitalisations). RESULTS Overall, men were more likely to have hospitalisations for COPD and had a higher proportion of death at hospital than did women. The 3-year cumulative incidence was 42.2/1,000 for the broadly defined COPD hospitalisation and 14.0/1,000 for the narrowly defined COPD hospitalisation, and steadily increased with increasing age. The relative risk for women versus men gradually increased with decreasing age, and was significantly greater than unity in the 55-59 year group for narrowly defined COPD hospitalisation. CONCLUSIONS In terms of impact on secondary care COPD is a disease of the elderly and is becoming more common in women, particularly in younger age groups.