Multiple sclerosis is associated with higher comorbidity and healthcare resource use: a population-based, case-control study in a western Mediterranean region.

BACKGROUND: Comorbidities are common in multiple sclerosis (MS), and have been associated with worse outcomes and increased healthcare resource usage. We studied the frequency of comorbidities and adverse health behaviors (AHB) in MS patients in the Mediterranean region of Catalonia.

METHODS: Population-based, case-control study using primary healthcare information covering 80% of Catalonia's population. Cases were matched by age/sex with randomly-chosen controls (ratio 1:5). Demographic information, comorbidities, AHB, annual visits, sick leave days and medication dispensing were studied. The association of comorbidities with MS and the profile of comorbidities according to sex within MS cases was assessed with multivariate logistic regression models, after adjusting for confounding variables. Healthcare resource usage was analyzed in MS cases compared to controls, and within MS cases in those with- compared to those without comorbidities.

RESULTS: 5,548 MS cases and 27,710 controls, 70% female, mean age 48.3 years were included. Stroke (OR 1.54; 95%CI 1.17-1.99), epilepsy (OR 2.46; 95%CI 1.94-3.10), bipolar disorder (OR 1.67; 95%CI 1.17-2.36) and depression (OR 1.83; 95%CI 1.70-1.98) were more frequent in MS. Cases were more prone to smoking but less to alcohol intaje. Among cases, psychiatric comorbidities were more frequent in women, whereas cardiovascular diseases and AHB were more frequent in men. MS patients, particularly with comorbidities, had higher healthcare resource usage than controls.

CONCLUSIONS: Psychiatric comorbidities, stroke, epilepsy, and AHB are more common in MS patients than in the general population in the western Mediterranean region of Catalonia. The presence of comorbidities increases the healthcare resource usage in MS patients.