Chronic lung disease and multiple sclerosis: Incidence, prevalence, and temporal trends

Abstract Objectives We aimed to estimate the incidence and prevalence of chronic lung disease (CLD), including asthma and chronic obstructive pulmonary disease, in the MS population versus a matched cohort from the general population. Methods We used population-based administrative data from four Canadian provinces to identify 44,452 persons with MS and 220,849 age-, sex- and geographically-matched controls aged 20 years and older. We employed a validated case definition to estimate the incidence and prevalence of CLD over the period 1995–2005, and used Poisson regression to assess temporal trends. Results In 2005, the crude incidence of CLD per 100,000 persons was 806 (95%CI: 701–911) in the MS population, and 757 in the matched population (95%CI: 712–803). In 2005, the crude prevalence of CLD was 13.5% (95%CI: 13.1–14.0%) in the MS population, and 12.4% (95%CI: 12.3–12.6%) in the matched population. Among persons aged 20–44 years, the average annual incidence of CLD was higher in the MS population than in the matched population (RR 1.15; 95%CI: 1.02–1.30), but did not differ between populations for those aged ≥45 years. The incidence of CLD was stable, but the prevalence of CLD increased 60% over the study period. Conclusion CLD is relatively common in the MS population. The incidence of CLD has been stable over time, but the prevalence of CLD has increased. Among persons aged 20–44 years, CLD is more common in the MS population than in a matched population. Given the prevalence of CLD in the MS population, further attention to the effects of CLD on outcomes in MS and approaches to mitigating those effects are warranted.