Multiple Sclerosis and Risk of Venous Thromboembolism: A Population-Based Cohort Study

Abstract

Background: Multiple sclerosis (MS) patients may be at increased risk of venous thromboembolism (VTE), but evidence is limited. Objectives: To examine long-term risk of VTE among MS patients. Patients and Methods: We conducted a population-based cohort study among 17,418 Danish MS patients and 87,090 comparison cohort members from the general population. Data on MS, VTE and comorbidities were obtained from the Danish National Registry of Patients including all admissions to Danish hospitals since 1977. We computed cumulative risks for VTE and adjusted incidence rate ratios (IRRs). Results: A total of 34 (0.2%) MS patients and 36 (0.04%) comparison cohort members had a deep venous thrombosis (DVT) within 1 year following the date of initial MS diagnosis/index date [adjusted IRR = 3.02 (95% CI: 2.14–4.27)]. During this period, 16 (0.09%) MS patients and 26 (0.03%) comparison cohort members had a documented pulmonary embolism (PE) [adjusted IRR = 2.85 (95% CI: 1.72–4.70)]. During the subsequent up to 29 years, 315 (1.9% of MS patients alive at year 1) MS patients had a record of a DVT [adjusted IRR = 2.28 (95% CI: 2.01–2.59)] and 129 (0.8%) had PE [IRR = 1.58 (95% CI: 1.31–1.92]. Conclusion: MS is a risk factor for VTE, but the absolute risk is low.

The risk of venous thromboembolism in patients with multiple sclerosis: the Clinical Practice Research Datalink

“…Our results are largely in agreement with those reported in recent epidemiological studies. A recent Danish study by Christensen et al . found a roughly 2‐fold increase in the occurrence rate of DVT and PE in MS patients.…”

“…Interpretation of the results of this initial study is, however, hindered by the lack of a description of the comparison group. In contrast, a recent Danish study reported an elevated risk of VTE associated with MS, with a 2‐ to 3‐fold increase in incidence rate among MS patients . However, this study lacked potentially important information on the presence of VTE risk factors (e.g.…”

Thrombotic Processes in Multiple Sclerosis as Manifestation of Innate Immune Activation

“…In a large population-based cohort study evaluating data from a 30-year Danish National Registry, MS was associated with increased long-term risk of venous thromboembolism (11). Another paper, based on the review of one cohort study and three cross-sectional studies, found that early MS was associated with an increased risk of pulmonary embolism, deep venous thromboembolism, and stroke, both the latter persisting over time (12).…”

Increased level of fibrinogen chains in the proteome of blood platelets in secondary progressive multiple sclerosis patients

“…15,16 An analysis of over 6000 patient deaths in the Danish National Registry of MS patients revealed that death by vascular or cardiac disease was the most frequently listed cause of death outside of MS itself. That is, ischaemic events are directly associated with irregular platelet functions and their prothrombotic activity.…”