Mortality in multiple sclerosis: meta-analysis of standardised mortality ratios

Objective There are inconsistent data on mortality in people with multiple sclerosis (MS). We performed a meta-analysis of all-cause, cause-specific and gender-specific crude mortality rates (CMRs), and standardised mortality ratios (SMRs) in MS, and estimated the rate of change of CMR and SMR over the past 50 years. Methods Medline, Embase and the Cochrane Library were searched. Keywords: 'Multiple Sclerosis' and ('standardised mortality' or 'standardized mortality'). Inclusion criteria: availability of data on the number of deaths; mean or median patient follow-up or reports of SMRs; being a longitudinal study. 12 studies were included covering the period 1949-2012 (27 423 patients; 6628 deaths; 437 832 person-years follow-up). CMR was calculated. SMRs were extracted. CMRs and natural logarithm of SMRs were pooled by the method of the inverse of the variance. Meta-regression models were used to investigate the secular trends. Results Pooled CMR was 9.78/1000 person-years (95% CI 6.81 to 14.02). Pooled all-cause SMR was 2.80 (95% CI 2.74 to 2.87). All-cause SMR was 2.56 (95% CI 2.47 to 2.66) in males and 3.06 (95% CI 2.97 to 3.17) in females. SMR due to cancer was 0.89 (95% CI 0.83 to 0.97). SMRs due to cardiovascular diseases, suicide, infection and respiratory diseases were 1.29 (95% CI 1.20 to 1.38), 2.13 (95% CI 1.80 to 2.51) and 2.91 (95% CI 2.60 to 3.26). There was no trend in CMRs, all-cause, and gender-specific SMRs. Conclusions The excess mortality in MS relative to the general population has not changed over the past 50 years. Female patients with MS have higher survival disadvantage compared to that of males. Death due to cardiovascular diseases, suicide and infection is higher in patients with MS compared to the general population.