Time to Initiation of Disease-Modifying Drugs after a Live Birth in Women with Multiple Sclerosis

Background: US data on disease-modifying drug (DMD) initiation after pregnancy are limited.

Objectives: To evaluate the time to initiation of DMDs after a live birth in women with multiple sclerosis (MS) using US administrative claims data.

Methods: A retrospective analysis of women with MS (ICD-9-CM code 340.xx), aged 18–65 years, a claim indicative of a live birth, 1-year continuous eligibility pre/post-pregnancy, and no evidence of DMD use in the third trimester of pregnancy in the IMS Health Real World Data Adjudicated Claims US database was conducted. The proportion of women initiating a DMD within 1-year post-delivery was evaluated. For women who initiated a DMD, the time to first DMD (calculated as the time between the live birth and the date of first DMD prescription) was assessed.

Results: Of 190,475 women with MS, 2,094 met eligibility criteria. Mean ± standard deviation (SD) age was 30.26 ±4.68 years. Most had commercial health insurance (98.62%), and were from the Midwest (32.34%), South (30.67%), or Northeast (28.70%) regions. The proportion with a live birth initiating a DMD within 1 year was 28.46%, and the proportion with no DMD within 1 year was 71.54%. For those initiating a DMD within 1 year, mean ±SD time from live birth to first DMD treatment was 118.98 ±92.94 days, and median time to first DMD was 93.50 days. A total of 16.11% received a DMD <30 days after live birth, approximately half initiated a DMD within 90 days (47.82%), and three-quarters initiated a DMD within 6 months (75.5%). The proportion of patients initiating DMDs within 1 year after live birth increased with higher numbers of pre-pregnancy relapses (0 relapses, n=441, 24.53%; 1 relapse, n=108, 50.94%; 2 relapses, n=33, 54.10%; ≥3 relapses, n=14, 60.87%). The mean ±SD and median number of days until DMD initiation for those receiving treatment within 1 year for 0 relapses was 123.57 ±96.02 (median 99); 1 relapse, 107.95 ±84.38 (median 80); 2 relapses, 120.76 ±83.63 (median 98); and ≥3 relapses, 55.57 ±37.88 (median 49.5) days. Patients treated with DMDs 1-year pre-pregnancy were more likely to initiate DMD treatment within 1 year (72.58% vs. 12.44% without DMD exposure 1-year pre-pregnancy). 

Conclusions: Less than one-third of women with MS and a live birth initiated a DMD within 1 year after delivery. The rate of DMD initiation increased with the number of relapses the patient experienced prior to pregnancy. Patients with more pre-pregnancy relapses initiated DMDs sooner.