Sickness absence rate increases years before clinical onset of MS

Swedish researchers have observed an increased risk of sick leave in MS patients several years before the clinical onset of the disease, highlighting the presence of prodromal symptoms in the development of MS. The authors concluded that analysing and monitoring sick-leave patterns may facilitate the early identification of people with a relatively high risk of MS.

Studies suggest that people who develop MS later often experience subtle symptoms in the preceding years, such as a somewhat higher rate of physician claims, hospital admission, and/or drug prescriptions [1]. A Swedish group examined annual sickness absence rates of up to 10 years before MS onset, using national administrative and registry data [2]. Dr Ali Manouchehrinia (Karolinska University, Sweden) said that the topic of prodromal MS is both intriguing and transformative in the understanding of MS, in the clinical management of MS, and in MS research. “A well-characterised prodromal phase of MS opens up a lot of opportunities for prevention strategies,” he noted. In this context, Dr Manouchehrinia cited earlier work from his group, which indicated that ≥13% of MS cases could have been prevented by avoiding smoking [3].

A novel outcome that the researchers could use was sickness absence benefits. Any resident in Sweden ≥16 years of age with income from work can obtain these benefits if their work capacity is reduced because of disease or injury. Two cohorts of patients were formed: cases identified via inpatient/outpatient registers (administrative cohort) or via the Swedish MS registry (clinical cohort). The administrative cohort comprised 8,640 cases and 43,259 matched controls; the clinical cohort 6,527 cases and 32,589 controls.

The results showed that sickness absence rates steadily increase in the years leading up to the diagnosis of MS, starting to rise as early as 10–12 years before clinical onset in the administrative cohort. The rate ratio peaked in the year prior to MS onset, when it was about 2.5 times higher than in controls. The pattern was similar in the clinical cohort. Dr Manouchehrinia concluded that analysing and monitoring sick-leave patterns may aid in timely MS diagnosis and intervention.

1. Wijnands JMA, et al. Lancet Neurol. 2017;16:445–451.
2. Manouchehrinia A, et al. The prodromal phase of multiple sclerosis: evidence from sickness absence patterns in the 10 years prior to disease onset: a matched cohort study. O184, MSMilan 2023, 11–13 October, Milan, Italy.
3. Manouchehrinia A, et al. Front Immunol. 2022;13:840158.

 

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Posted on 4 December, 2023