Adherence to Multiple Sclerosis Disease-Modifying Therapy Lowers Risk of Relapse, Severe Relapse
The study added to the evidence base for recommending adherence to treatment with disease-modifying therapies in clinical practice, a key element for reducing moderate or severe relapse rate.
Laura Belotti
Similar to previously published data, new findings from a population-based cohort study of Italian adults with multiple sclerosis (MS) showed that a high level of adherence to disease-modifying therapies (DMTs) is associated with a lower risk of moderate or severe relapse. Above all, these data reinforce the importance of the choice of which drug to start MS treatment.
Led by Laura Belotti, an epidemiologist at the Institute of Neurological Sciences of Bologna, the analysis included 2528 patients with MS from Northern Italy who were receiving a first-ever treatment with DMD between 2015 and 2019. Each patient was followed from the index date until either the date of the first relapse, the date of death, the date of emigration from the Emilia-Romagna region (E-RR) or the end of the study period, whichever came first.
The outcome of interest, first moderate or severe relapse, was carried out through an algorithm that was validated via clinical and radiological criteria by neurologists with expertise in MS management. It required the presence of at least 1 of the following: hospitalization with primary diagnosis of MS; access to the emergency department with primary diagnosis of MS; and use of systemic corticosteroids at a dosage of at least 0.5 g/day for 5 days.
During the follow-up, 13% (n = 341) of the cohort had at least 1 moderate or severe relapse. Adherence to DMD was explained as the Proportion of Days Covered (PDC), otherwise the ratio between the cumulative number of days in which the DMDs were available and the overall follow-up. The study investigators categorized rates of adherence into non-adherence (PDC <60%), moderate adherence (60% ≤ PDC <80%), and high adherence (PDC ≥80%).
Compared with the non-adhered group, the relapse hazard ratio (HR) decreased progressively as the level of adherence increased from moderate (HR, 0.79; 95% CI, 0.55-1.14) to high (HR, 0.77; 95% CI, 0.60-0.998). In a multivariate analysis that adjusted for age and sex, the HR of moderate or severe relapses for moderately adherent patients with MS decreased but did not reach statistical significance (HR, 0.76; 95% CI, 0.53-1.10), while highly adherent patients had a 25% lower hazard of experiencing a moderate or severe relapse than non-adherent patients (HR, 0.75; 95% CI, 0.58-0.98).
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"By increasing the buffer period, i.e., excluding PwMS with minimum follow-up of less than 30, 90 and 180 days, respectively, the protective effect of high adherence seemed to be attenuated, suggesting that adherence to DMD therapy was particularly protective in the early stages of treatment,” the study authors noted.
Using Kaplan-Meier methods, a time-to-event analysis showed that the probability of relapse-free survival dropped to 75% (95% CI, 71-78) after 1705 days, corresponding to 4.7 years. Over the 5 years of follow-up, investigators observed changes in the prescription patterns of patients, with notable increases in the number of oral and infusion drugs as a first option. Additionally, in 2019, there was a 28% increase in the number of new DMD users, mainly in part to the increased prescription of dimethyl fumarate and ocrelizumab (Ocrevus; Genentech).
"In previously untreated patients with MS, such as the ones included in our study, the choice of which DMD to start treatment with is therefore particularly important and needs a thorough discussion between the treating clinician and patient, considering not only the severity and stage of the disease, but also the patient's attitudes, preferences and expectations," the study authors wrote. "Indeed, oral medications offer the advantage of self-administration but require high adherence to a daily administration schedule."
They added, "conversely, drugs delivered by infusion may be administered less often (once or twice a year) but require access to healthcare facilities, preparation and more complex management for both the patient and health care services."
