Multiple cause of death analysis in multiple sclerosis: A population-based study.

OBJECTIVE: To gain a better understanding of the complex patterns of causes that contribute to death due to multiple sclerosis (MS) by assessing the relationship between MS and other causes of death listed on death certificates.

METHODS: Multiple cause of death data for all adult deaths (aged ≥18 years) in British Columbia, Canada, between 1986 and 2013 were accessed. All causes, as listed on the death certificate, whether underlying or contributing, were considered "any mention" causes. The associations between mention of MS on the death certificate and mention of other causes of death were examined by logistic regression, adjusted for age, sex, and calendar year (Bonferroni-corrected α level = 0.002). Findings were also sex-stratified.

RESULTS: Among 771,288 deaths, MS was mentioned on 2,153 certificates. If MS was mentioned (versus not mentioned), there was a greater chance that specific conditions contributed to the death: respiratory infection (adjusted odds ratio [aOR], 3.03 [95% confidence interval (CI), 2.73-3.36]), aspiration pneumonia (aOR, 7.15 [95% CI, 6.23-8.22]), urinary tract infection (UTI) (aOR, 10.2 [95% CI, 8.7-12.0]), other infection including sepsis (aOR, 1.34 [95% CI, 1.15-1.56]), and skin disease (aOR, 5.06 [95% CI, 3.96-6.46]). Sex differences existed for urinary tract infection (men: aOR, 14.9 [95% CI, 11.5-19.3]; women: aOR, 8.00 [95% CI, 6.53-9.81]) and chronic respiratory disease (men = aOR, 1.36 [95% CI, 1.14-1.63]; women = aOR, 0.97 [95% CI, 0.84-1.13]).

CONCLUSIONS: Deaths attributed to MS were commonly caused by infection (especially respiratory and urinary tract-related); conditions associated with advanced disability and immobility, such as aspiration pneumonia; and chronic respiratory disease in men. All are potentially modifiable; interventions that reduce the frequency or severity of these complications could improve survival in MS.