ORLANDO—Patients with multiple sclerosis (MS) have a 14-year reduction in median life expectancy from onset of the disease, compared with the general population, according to a 60-year Norwegian study presented at the ACTRIMS 2017 Forum. The standardized mortality ratio (SMR) may be nearly threefold higher in patients with MS, compared with controls, and sevenfold higher in patients who are the youngest at onset.
Studying survival and causes of death in MS helps researchers gain knowledge about environmental factors that affect MS susceptibility and clinical course. “We therefore aimed to investigate survival and causes of death in a population-based cohort during 60 years,” said Nina Grytten, PhD, researcher at the Norwegian MS Competence Centre at Haukeland University Hospital in Bergen, and colleagues.Approximately 1,388 patients with MS with onset between 1953 and 2012 in Hordaland County, Western Norway, participated in the study. Dr. Grytten and colleagues obtained information from patient records at Haukeland University Hospital, and it was linked to the Causes of Death Registry. They estimated survival from disease onset, adjusted for sex, age, and disease course, using the Kaplan-Meier analyses. In addition, researchers used the SMR to examine mortality and causes of death in MS.
In all, 291 patients died, primarily from MS. The median time to death from MS onset was 41 years for all patients, compared with 55 years for the general population. Women with MS had a 43-year median life expectancy from onset, compared with 56 years in the general female population. Men had a 36-year median life expectancy from MS onset, compared with 50 years in the general male population. Patients with relapsing-remitting MS had a 43-year median life expectancy from onset, and individuals with primary progressive MS had a 26-year median life expectancy from onset.
The SMR was 2.7 in the total MS population. SMR was 2.4 in patients with relapsing-remitting MS and 3.9 in patients with primary progressive MS. In addition, SMR was 2.9 in women with MS and 2.5 in men with MS. Patients with onset at age 20 or younger had an SMR of 7.3. For patients age 21 to 30 at onset, SMR was 4.0. SMR was 2.6 for patients age 31 to 40 at onset. SMR was 1.3 in patients who were age 60 or older at onset.
SMR from disease onset during the period from 1953 to 1974 was 3.1. SMR from disease onset between 1975 and 1996 was 2.6, and SMR from disease onset between 1997 and 2012 was 0.7. Among causes of death, the SMR for cancer was 5.4, that for respiratory causes and infections was 4.5, and that for coronary and cerebrovascular causes was 3.28. The SMR of causes of death indicated serious comorbid disease in MS, said the investigators.
Female patients with MS had a longer median time to death, compared with male patients, but had a higher risk of dying than did the general population. Investigators also observed a decrease in mortality throughout the study, which might be attributed to environmental factors such as lifestyle and treatment.
—Erica Tricarico
Suggested Reading
Grytten Torkildsen N, Lie SA, Aarseth JH, et al. Survival and cause of death in multiple sclerosis: results from a 50-year follow-up in Western Norway. Mult Scler. 2008; 14(9):1191-1198.