To Örebro University

Introduction: The cardiovascular disease (CVD) rate among multiple sclerosis (MS) patients has been shown to be elevated; however, studies involving more recently diagnosed patients are rare. Here we estimated the rate of CVD in patients before and after MS diagnosis as compared with a matched MS-free population.

Methods: Incident MS patients diagnosed in 2008-2016 were identified in the Swedish National Patient Register. MS patients were matched with 10 MS-free individuals by age, sex, and region of residence. Incidence rates (IR) per 10,000 person-years (PY) and incidence rate ratios (IRR) of cardiovascular outcomes were calculated after MS diagnosis (equivalent date for those without MS) and among those with no history of CVD before this date.

Results: In total, 6,602 MS patients and 61,828 without MS (female, 69%; median age, 40 years) were identified. Before MS diagnosis, patients showed higher proportions of stroke (2.0% vs 0.6%), transient ischaemic attack (TIA) (0.4% vs 0.2%) and peripheral vascular disease (0.3% vs 0.2%) compared with the MS-free cohort. The year before MS diagnosis, larger proportions were prescribed diuretics (8.4% vs 6.9%), peripheral vasodilators (1.4% vs 1.0%), lipid-modifying agents (5.6% vs 4.8%), and calcium channel blockers (3.7% vs 3.1%).After MS diagnosis, patients had a higher risk of major adverse cardiovascular events (MACE) (IRR 1.35; 95% confidence interval [CI] 1.06-1.71), heart failure (HF) (IRR 1.36; 95% CI 1.02-1.80), and TIA (IRR 1.59; 95% CI 1.05-2.42) compared with the MS-free cohort. The risk of bradycardia (IRR, 2.61; 95% CI 1.14-5.97) was higher only in MS patients with no history of CVD. CVD incidence rates in MS patients were comparable between sexes except for the HF rate, which was higher among males (28.28 per 10,000 PY, 95% CI 18.79-40.87) than females (11.81 per 10,000 PY, 95% CI 7.71-17.30). The relative risk of MACE (IRR 2.40; 95% CI 1.15-5.00), TIA (IRR 7.03; 95% CI 2.62 -18.87), HF (IRR 3.28; 95% CI 1.46-7.37), and bradycardia (IRR 4.51; 95% CI 1.54-13.20) were higher among younger MS patients (aged < 40 years at diagnosis).

Conclusions: After MS diagnosis, MS patients showed an increased incidence of MACE, TIA, and HF compared with those without MS, irrespective of CVD history. The age-matched rela-tive risk was particularly high among younger MS patients. In particular, the relative risk of bradycardia was only higher among younger patients and patients with no history of CVD.