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Multiple sclerosis risk from anti-diabetic medication dependent on patient age

The risk of developing multiple sclerosis in those prescribed anti-diabetic medication is either higher or lower depending on their age.

Patients aged 45 years and older with type 2 diabetes prescribed anti-diabetic medication, have an increased risk of developing multiple sclerosis compared to younger patients, but in the younger age group, the risk is actually significantly reduced according to the findings of a study by US researchers based at the university of Arizona.

Globally, an estimated 2.8 million people live with multiple sclerosis (MS) and the prevalence has increased in every world region since 2013, with a pooled incidence across 75 countries of 2.1 per 100,000 persons/year.

Moreover, there is a good deal of data to suggest that axonal degeneration is the major determinant of irreversible neurological disability in patients with MS.

Although the precise underlying cause for MS remains to be determined, observational research suggests both genetic and environment influences and which are widely believed to be autoimmune in nature.

Nevertheless, one prospective study following people for nine years, demonstrated a moderate but significant association of type 2 diabetes with MS incidence.

In addition, it has also been found that patients with type 1 diabetes have a more than three-fold increased risk of developing MS.

Given the association with diabetes, the US researchers wondered if the use of anti-diabetic medication might positively impact on the risk of developing MS. The team turned to a US insurance claims database and identified those with type 2 diabetes and set the index data as the first recorded entry of their type 2 diabetes (T2D) diagnosis and the start date of the study, as 12 months after this index date.

For their analysis, researchers categorised participants with T2D as either under or over 45 years of age and propensity matched both cohorts, based on several factors including age, gender and co-morbidities.

Multiple sclerosis risk and use of anti-diabetic medication

A total of 143,613 individuals prescribed anti-diabetic medication (mean age of 30.16 years) and 638,625 (mean age of 61.85) were identified and both groups propensity matched.

Among the younger diabetic cohort, there was a significantly reduced risk of developing multiple sclerosis (relative risk, RR = 0.22, 95% CI 0.17 – 0.29, p < 0.001).

In contrast, among the older cohort, the risk of developing MS was actually significantly higher (RR = 1.36, 95% CI 1.25 – 1.47, p < 0.001). The increased or decreased risk was also apparent for both sexes although among older men the risk was only slightly elevated (RR = 1.17, 95% CI 1.01 – 1.37, p = 0.04).

Interestingly, when researchers considered the individual anti-diabetic medicines, the risk was higher (or lower for younger patients) for all classes e.g., insulin, metformin, sulfonylureas, glitazones, DPP4 inhibitors and the combination of metformin and sulfonylureas.

The authors concluded that exposure to anti-diabetic medication in those with type 2 diabetes either increased or decreased the subsequent risk of developing multiple sclerosis and that this elevated or reduced risk was age-dependent.

Branigan GL et al. Age and sex differences on anti-hyperglycemic medication exposure and risk of newly diagnosed multiple sclerosis in propensity score matched type 2 diabetics. Heliyon 2022.

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