Beta‐interferon exposure and onset of secondary progressive multiple sclerosis

Abstract

Background and purposeBeta‐interferons (IFNβ) are the most widely prescribed drugs for patients with multiple sclerosis (MS). However, whether or not treatment with IFNβ can delay secondary progressive MS (SPMS) onset remains unknown. Our aim was to examine the association between IFNβ exposure and SPMS onset in patients with relapsing−remitting MS (RRMS).MethodsA retrospective cohort study using British Columbia (Canada) population‐based clinical and health administrative data (1985–2008) was conducted. RRMS patients treated with IFNβ (n = 794) were compared with untreated contemporary (n = 933) and historical (n = 837) controls. Cohort entry was the first clinic visit during which patients became eligible for IFNβ treatment (baseline). The outcome was time from baseline to SPMS onset. Cox regression models with IFNβ as a time‐dependent exposure were adjusted for sex, and baseline age, disease duration, disability, *socioeconomic status and *comorbidities (*available for the contemporary cohorts only). Additional analyses included propensity score adjustment.ResultsThe median follow‐up for the IFNβ‐treated, untreated contemporary and historical controls were 5.7, 3.7 and 7.3 years, and the proportions of patients reaching SPMS were 9.2%, 11.8% and 32.9%, respectively. After adjustment for confounders, IFNβ exposure was not associated with the risk of reaching SPMS when either the contemporary or the historical untreated cohorts were considered (hazard ratio 1.07; 95% confidence interval 0.93–1.48, and hazard ratio 1.04; 95% confidence interval 0.74–1.46, respectively). Further adjustments and the propensity score yielded results consistent with the main analysis.ConclusionsAmongst patients with RRMS, use of IFNβ was not associated with a delayed onset of SPMS.

Association between the use of selective serotonin reuptake inhibitors and multiple sclerosis disability progression

“…Follow‐up data to the end of 2008 were linked and stripped of all personal identifiers . This same linked dataset has been used for previous MS‐related studies …”

“…The primary disability outcome was a sustained EDSS score of 6.0 (confirmed after at least 6 months with no subsequent improvement as described in previous studies 1,3 ). An EDSS score of 6 indicates 'intermittent or unilateral constant assistance' (cane, crutch, brace) required to walk about 100 m with or without resting.…”

“…All patients with MS are at risk of disability progression over time, typified by worsening of physical ability. There is a need for better access to effective drugs to prevent or slow progression in MS. [1][2][3] The repurposing of already approved drugs to alter progression in MS has been cited as a key research priority. 4 This 'repurposing' or reuse of drugs that are already available for a different condition is a growing area in medicine.…”

Estimating inverse probability weights using super learner when weight-model specification is unknown in a marginal structural Cox model context

“…We apply the methodology described in this paper to the British Columbia MS cohort data (1995-2008) [15,[23][24][25][52][53][54][55][56][57] to estimate the effect of -interferon (IFN) on time to irreversible disability progression. In this study, irreversible progression of disability is measured by sustained expanded disability status scale (EDSS) 6, which is confirmed after at least 150 days, with all subsequent EDSS scores being 6 or greater.…”

Advances in neurological research and practice

“…Multiple sclerosis (MS) is a field of neurology that has undergone tremendous advances within only the last 15 years . The advent of immunological therapies has transformed outcome for patients with relapsing−remitting disease, although the effect on chronic progressive disease is less certain.…”