Comorbid disease burden among MS patients 1968-2012: A Swedish register-based cohort study.

Affiliation

Smith KA(1), Burkill S(2), Hiyoshi A(3), Olsson T(4), Bahmanyar S(5), Wormser D(6), Geissbühler Y(7), Moore A(7), Kharat V(8), Montgomery S(9).
Author information:
(1)Clinical Epidemiology Unit, Department of Medicine, Solna, Karolinska Institutet, Stockholm, Sweden/Department of Translational Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
(2)Clinical Epidemiology Unit, Department of Medicine, Solna, Karolinska Institutet, Stockholm, Sweden/Centre for Pharmacoepidemiology, Department of Medicine, Solna, Karolinska Institutet, Stockholm, Sweden.
(3)Clinical Epidemiology and Biostatistics, School of Medical Sciences, Örebro University, Örebro, Sweden/Department of Public Health Sciences, Stockholm University, Stockholm, Sweden.
(4)Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden/Centre for Molecular Medicine, Karolinska University Hospital, Stockholm, Sweden.
(5)Clinical Epidemiology Unit, Department of Medicine, Solna, Karolinska Institutet, Stockholm, Sweden/Centre for Pharmacoepidemiology, Department of Medicine, Solna, Karolinska Institutet, Stockholm, Sweden/Centre for Psychiatry Research, Karolinska Institutet, Stockholm, Sweden.
(6)F. Hoffmann-La Roche Ltd., Basel, Switzerland.
(7)Novartis Pharma AG, Basel, Switzerland.
(8)Novartis Pharmaceuticals Corporation, East Hanover, NJ, USA.
(9)Clinical Epidemiology Unit, Department of Medicine, Solna, Karolinska Institutet, Stockholm, Sweden/Clinical Epidemiology and Biostatistics, School of Medical Sciences, Örebro University, Örebro, Sweden/Department of Epidemiology and Public Health, University College London, London, UK.

Abstract

BACKGROUND: People with multiple sclerosis (pwMS) have increased comorbid disease (CMD) risk. Most previous studies have not considered overall CMD burden. OBJECTIVE: To describe lifetime CMD burden among pwMS. METHODS: PwMS identified using Swedish registers between 1968 and 2012 (n = 25,476) were matched by sex, age, and county of residence with general-population comparators (n = 251,170). Prevalence, prevalence ratios (PRs), survival functions, and hazard ratios by MS status, age, and time period compared seven CMD: autoimmune, cardiovascular, depression, diabetes, respiratory, renal, and seizures. RESULTS: The magnitude of the PRs for each CMD and age group decreased across time, with higher PRs in earlier time periods. Before 1990, younger age groups had higher PRs, and after 1990, older age groups had higher PRs. Male pwMS had higher burden compared with females. Overall, renal, respiratory, and seizures had the highest PRs. Before 2001, 50% of pwMS received a first/additional CMD diagnosis 20 years prior to people without MS, which reduced to 4 years after 2001. PwMS had four times higher rates of first/additional diagnoses in earlier time periods, which reduced to less than two times higher in recent time periods compared to people without MS. CONCLUSION: Swedish pwMS have increased CMD burden compared with the general population, but this has reduced over time.