Weight and BMI Changes over 7 Years in CombiRx

Background: The CombiRx trial was a double blind, multi-center randomized clinical trial with 1008 persons with relapsing remitting MS, comparing 50% of participants on interferon beta 1a (IFN) and glatiramer acetate (GA) treatment versus 25% on each of the single agent arms with matching placebo.  Entry criteria include: EDSS ≤ 5.5, RRMS diagnosed by Poser or McDonald criteria, 18-60 years of age, at least 2 relapses in prior 3 years, no prior use of either medication.  Participants were followed for up to 7 years with both clinical and MRI measures.

 

Objectives: Describe changes in weight and body mass index (BMI) in CombiRx over 7 years.

 

Methods: Participants were randomized and followed with quarterly visits, including vital signs, through month 42 and every 6 months from month 48 for up to 7 years. The trial concluded in March 2012 with 80.1% (814/1008) completing 3 years and 84.4% (687/814) entering with 85.0% (584/687) completing the extension phase. Results are reported as mean (SD), change from baseline assessed by covariate adjusted ANOVA with Tukeys HSD adjustment for multiple comparisons and logisitic regression; p-value < 0.05 considered meaningful. BMI was calculated from weight at each visit and baseline height.

Results:Baseline weight 180.4(46.0) pounds and BMI 28.7(6.8), no differences by treatment group. Males and females had similar BMI (p=0.98), with African Americans having higher weight (p=0.043) and BMI (p=0.040) compared to Caucasians. With an average follow up of 3.9(1.6) years, change in weight was related to starting weight, age and years of follow up; those on GA alone had a significant mean increase of 2.4 lbs compared to a non-significant loss of 1.9 for IFN alone (GA vs IFN, p=0.023) or significant gain of 1.3 IFN+GA (GA vs IFN+GA, p=0.75). Similarly change in BMI was related to starting BMI; GA had a higher increase compared to IFN (0.5 vs -0.4, p = 0.0496) but not IFN+GA (0.5 vs 0.3; p=0.09). On GA alone 53.7% gained more than 1 lb (53.7%) compared to IFN (42.9%, p=0.029) but similar to IFN+GA (53.7%, p=0.57). There were no gender or race differences in changes in weight or BMI on study.

 

Conclusions: Growing interest in MS comorbidities makes weight changes important to understand and investigate.  There was differential weight gain based on treatment received. A higher proportion of participants gained weight on GA compared to IFN. More detailed exploration of weight changes and reasons for weight gain will be presented.