Multiple sclerosis is associated with higher comorbidity and health care resource use: A population‐based, case–control study in a western Mediterranean region

Background and purpose Comorbidities are common in multiple sclerosis (MS), and have been associated with worse outcomes and increased health care resource usage. We studied the frequency of comorbidities and adverse health behaviors (AHBs) in MS patients in the Mediterranean region of Catalonia. Methods This population‐based, case–control study used primary health care information covering 80% of Catalonia's population. Cases were matched by age/sex with randomly chosen controls (ratio = 1:5). Demographic information, comorbidities, AHBs, 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 were assessed with multivariate logistic regression models, after adjusting for confounding variables. Health care resource usage was analyzed in MS cases compared to controls, and within MS cases in those with compared to those without comorbidities. Results Five thousand five hundred forty‐eight MS cases and 27,710 controls (70% female, mean age = 48.3 years) were included. Stroke (odds ratio [OR] = 1.54, 95% confidence interval [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 intake. Among cases, psychiatric comorbidities were more frequent in women, whereas cardiovascular diseases and AHBs were more frequent in men. MS patients, particularly with comorbidities, had higher health care resource usage than controls. Conclusions Psychiatric comorbidities, stroke, epilepsy, and AHBs are more common in MS patients than in the general population in the western Mediterranean region of Catalonia. The presence of comorbidities increases the health care resource usage in MS patients. We conducted a population‐based case–control study, with more than 30,000 subjects, aimed at addressing the risk of comorbidities and adverse health behaviors in multiple sclerosis (MS) patients compared to controls. After adjusting for confounding variables, we found an increased risk of epilepsy, depressive disorder, bipolar disorder, and stroke, as well as increased adverse health behaviors in MS patients compared to controls. We also found increased health care resource usage in MS patients compared to controls, and among MS patients, in those with comorbidities.