The epidemiology and healthcare costs of community-acquired pneumonia in Ontario, Canada: a population-based cohort study

Objectives The aim of the present study was to determine incidence-based short- and long-term healthcare costs attributable to community-acquired pneumonia (CAP) from the healthcare payer perspective in Ontario, Canada. Methods We conducted a retrospective population-based matched cohort study of residents in Ontario, Canada using health administrative data. We identified subjects with an incident episode of CAP (exposed subjects) between 1 January 2012 and 31 December 2014. The index date of each episode was based on the first inpatient or outpatient claim for pneumonia. Exposed subjects were matched without replacement to unexposed subjects from the general population using hard and propensity score matching on age, sex, income quintile, rural residence, comorbidities, and healthcare costs prior to index date. Attributable costs represented the mean difference in costs between the exposed subjects and their matched pairs. Results We identified 692,090 subjects with at least one episode of CAP between 1 January 2012 and 31 December 2014. Adults aged 65 years and older had the highest annual incidence rate of 50.1 episodes per 1,000 person-years, while adults aged 18-64 years and children (aged 0-17) had incidence rates of 12.9 and 24.7 episodes per 1,000 person-years, respectively. The majority of episodes involved care exclusively in the outpatient setting (92.6%), with most of these episodes involving a single physician visit. The mean attributable costs were $1,595 (95% CI: $1,572-$1,616) per outpatient CAP episode and $12,576 (95% CI: $12.392-$12,761) per inpatient CAP episode. Attributable costs were significantly higher for adult subjects and those with time spent in the intensive care unit. Alternative case definitions yielded different results, although demonstrated the same overall trends across groups. Conclusion CAP is associated with substantially increased acute and long-term healthcare costs compared to unexposed subjects. This study highlights the burden of CAP in both the inpatient and outpatient setting, and will serve to inform strategic healthcare planning for future interventions and healthcare programs.