Multiple sclerosis by phenotype in Germany

A diagnosis of multiple sclerosis (MS) can be categorized based on its disease course into the following phenotypes: relapsing-remitting MS (RRMS), primary progressive MS (PPMS), and secondary progressive MS (SPMS). With one exception, studies of MS by phenotype either provide only prevalence data or if describing drug utilization, the emphasis is on patients with RRMS; while drug utilization by phenotype tends to be examined over the course of a year. No recent studies have comprehensively evaluated MS phenotypes by prevalence, drug utilization, and comorbidities over time from a population-based perspective, which is essential for understanding the disease burden and identifying unmet needs in MS. Germany is one of the few countries where specific MS phenotypes are commonly recorded in routine clinical practice. The purpose of this study was to compare MS phenotypes with respect to changes in their population-based prevalence rates and the types of MS treatments prescribed over time, as well as the frequency of clinical conditions associated with MS based on data from a German health insurance database.

This retrospective, observational, cohort study used data from a German health insurance database for the period 2010 to 2017. Patients aged 18+ years with a specified phenotype of MS based on ICD-10 diagnosis coding were included in the analysis.

In 2010, RRMS was reported in 73%, PPMS in 8%, and SPMS in 19% of patients with MS with a known phenotype. The mean ages of patients were 41.4, 53.6, and 52.8 years, respectively, and all phenotypes were associated with a female predominance (69%, 63% and 63%, respectively). The prevalence rate of each phenotype markedly increased during the study period (RRMS +113%, PPMS +40%, SPMS +54%; in 2017 the rates were 183, 14, and 34 per 100,000, respectively). The mean age of patients reporting each phenotype also increased (p<0.01), while the female:male proportion remained stable in RRMS and SPMS, the proportion of females significantly declined over time in the PPMS group. The overall percentage of patients prescribed a disease-modifying drug increased across the phenotypes from 51% to 57%. Prescription of interferon-based therapies declined in each phenotype, with the greatest declines observed in RRMS and PPMS. The PPMS and SPMS groups had significantly more prescriptions for symptom management than the RRMS group. Depression was the most prevalent clinical condition associated with each phenotype. There was a significant difference in the percentage of patients with depression across the phenotypes (p = 0.03), with the highest among SPMS (44%) compared with RRMS (35%) or PPMS (37%). Significant differences (p<0.05) across the phenotypes were also observed for the composite prevalence of cardiovascular conditions (highest in PPMS) and cognitive dysfunction (highest in SPMS).

The increasing numbers of patients across each MS phenotype, aging population in patients with MS regardless of phenotype, gender differences and variations across the types of treatments prescribed, and clinical conditions associated with each MS phenotype present new insight into the disease burden and treatment strategies of MS. These should be considered when developing healthcare strategies and optimizing care for patients with MS.