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Published on: December 9, 2015
Risk of serious infections in multiple sclerosis patients by disease course and disability status: Results from a
Judith S Brand1, Kelsi A Smith2, Fredrik Piehl3
1Clinical Epidemiology and Biostatistics, School of Medical Sciences, Örebro University, Sweden.
Background And Objectives:
Serious infections are an emerging concern with increasing use of potent immunomodulation in multiple sclerosis (MS), but the extent to which MS disease features influence infectious susceptibility is poorly characterized. The objective of this study was to assess the associations of MS disease course and disability status with risk of serious infections.
Methods:
A cohort of 8660 MS patients was individually matched on age, sex and region of residence with 86,600 people without MS from the general population using national registers in Sweden. The study period was from 1996 to 2012, with follow-up until December 31, 2014. The main outcomes were infection as the underlying or contributory cause of death or infection-related hospital admission identified in the Cause of Death and Patient registers. MS disease course (relapsing-remitting or progressive disease) and Expanded Disability Status Scale (EDSS) score (six and over or below six) were extracted from the MS Register Hazard ratios (HRs) for any serious infection were estimated using flexible parametric models.
Results:
During a median follow-up of 9.6 years (interquartile range = 5.5-13.5 years), 1337 MS patients experienced a serious infection. Compared with individually matched people without MS, risk of serious infection was greater for progressive disease (HR = 3.80; 95% CI 3.52: 4.09) than relapsing-remitting disease (HR = 1.77; 95% CI: 1.62:1.93). A similar pattern of risk was seen for dichotomised EDSS score (HR = 4.26; 95% CI 3.87: 4.70 for EDSS 6.0-9.5 and HR = 1.30; 95% CI 1.1853: 1.43 for EDSS 0.0-5.5). Overall, associations with greater disability did not notably differ by immunomodulatory therapy use, but associations with lower disability were more pronounced in patients receiving these therapies.
Conclusions:
Disease course or EDSS score (which may be more readily available than MS course in some patients) should be considered in individual management and monitoring of MS patients, including assessing benefit-risk of therapies that influence general immune function.
Insights
Multiple sclerosis (MS) patients with progressive disease or higher disability (EDSS score ≥6.0) face a significantly higher risk of serious infections. These factors are crucial for managing MS and assessing treatment risks.
Area of Science:
- Neurology
- Immunology
- Infectious Diseases
Background:
- Serious infections are a growing concern in multiple sclerosis (MS) management, particularly with potent immunomodulatory therapies.
- Understanding how MS disease characteristics influence infection risk is crucial but poorly understood.
Purpose of the Study:
- To investigate the association between multiple sclerosis disease course and disability status with the risk of serious infections.
- To inform clinical management and risk-benefit assessments of immunomodulatory treatments in MS patients.
Main Methods:
- A large cohort study in Sweden (1996-2014) matched 8660 MS patients with 86,600 controls.
- Infection risk was assessed based on disease course (relapsing-remitting vs. progressive) and Expanded Disability Status Scale (EDSS) scores.
- Flexible parametric models were used to estimate hazard ratios for serious infections.
Main Results:
- MS patients had a higher risk of serious infections compared to the general population.
- Progressive MS (HR=3.80) and higher disability (EDSS 6.0-9.5, HR=4.26) were associated with substantially increased infection risk.
- Relapsing-remitting MS (HR=1.77) and lower disability (EDSS 0.0-5.5, HR=1.30) also showed increased risk, more pronounced with immunomodulatory therapy.
Conclusions:
- MS disease course and disability status (EDSS) are key factors influencing serious infection risk.
- These factors should guide individual patient management, monitoring, and the assessment of immunomodulatory therapy benefits and risks.
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