Multiple Sclerosis Survival Improving

May 29, 2015

Survival is improving among patients with multiple sclerosis (MS) but remains around 7 years lower than in the general population, a new study has shown.

The study, published online in Neurology on May 27, evaluated administrative health data and death records for the population of the province of Manitoba, Canada, from 1984 to 2011. They identified 5797 persons with MS and compared their survival with that of 28,807 controls matched for sex, year of birth, and region.

Results showed that median duration of survival from birth in the MS population was 75.9 years vs 83.4 years in the matched population.

"Most individuals with MS can expect to live long lives," lead author, Ruth Ann Marrie, MD, University of Manitoba, Winnipeg, Canada, commented to Medscape Medical News. "However, there is still a gap of around 6 to 7 years between MS patients and the general population."

She noted that previous work has estimated a 10-year mortality gap, so these results suggest that the gap may be shortening.

"We looked at a long window, and our results suggest that MS patients are now living longer than they used to," she said. "This could simply be a reflection of what's going on in the general population or it could be related to factors specific to MS. We can't tell that from this data."

Dr Marrie said the data could not address the question of whether the longer survival could have been due to the introduction of more effective treatments. "We didn't specifically evaluate MS treatments. Some of the period studied in our paper was before the disease-modifying treatments became available, but it is possible these drugs have had an effect. This is something that needs to be evaluated."

The researchers found that over the entire study period, after adjustment for year, age-specific mortality was higher in the MS population than in the matched population. The relative risk for death in the MS population was greatest at younger ages: 3.65 in those under age 40 years and 2.88 in those aged 40 to 59 years vs 1.80 at age 80 years and older.

The study also showed that 44% of patients with MS were reported to have died of MS and related complications, and this changed relatively little over the study period. Other common causes of death were cardiovascular disease, cancer, and respiratory disease.

Effect of Comorbidities

Several comorbidities were independently associated with increased hazard of death, including diabetes, ischemic heart disease, depression, and chronic lung disease.

"Comorbidities are important," Dr Marrie commented. "If you have MS then conditions such as diabetes and heart disease do increase mortality, but the effect is not worse than in non-MS patients."

She added: "We thought that the coexistence of MS and other conditions could be worse than additive — ie, a case of 2 plus 2 equals 5. But we did not find that. So we were pleasantly surprised by that. But all the same, comorbidities do impact on mortality, so we would advise MS patients to do everything they can to have a healthy lifestyle — ie, eat healthily, not to smoke, et cetera — to improve their survival."

Interestingly, migraine was associated with a reduced hazard of death in this study, which the researchers point out is consistent with previous findings that migraine was more common in women with a "benign" MS course.

This study was supported (in part) by operating grants and a Don Paty Career Development Award from the MS Society of Canada and a Manitoba Research Chair from Research Manitoba. Dr Marrie receives research funding from the Canadian Institutes of Health Research, Public Health Agency of Canada, Manitoba Health Research Council, Health Sciences Centre Foundation, Multiple Sclerosis Society of Canada, Multiple Sclerosis Scientific Foundation, and Rx&D Health Research Foundation. She has conducted clinical trials funded by Sanofi-Aventis.

Neurology. Published online May 27, 2015. Full text


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