Table 2

Standardised mortality ratios and relative mortality ratios for the British Columbia multiple sclerosis cohort

Observed deathsExpected deaths*SMR† (95% CI)RMR‡ (95% CI)p Value for RMR
Overall (n=6841§)10253562.88 (2.71 to 3.06)
Sex
 Men3901462.68 (2.43 to 2.96)Referent 1.15 (1.01 to 1.31)0.03
 Women6352113.01 (2.79 to 3.25)
Disease course
 Relapsing onset7842732.87 (2.68 to 3.08)Referent 1.53 (1.30 to 1.80)<0.0001
 Primary progressive236822.89 (2.54 to 3.28)
Age at onset (years)
 <2093214.49 (3.67 to 5.51)Referent
 20–<30288783.71 (3.31 to 4.17)0.83 (0.65 to 1.04)0.11
 30–<40304963.16 (2.82 to 3.53)0.76 (0.60 to 0.96)0.02
 ≥403361622.08 (1.87 to 2.31)0.62 (0.48 to 0.80)0.0002
Time period (n=4109)**
 1980–1985126482.60 (2.19 to 3.10)Referent
 1986–199188412.16 (1.75 to 2.66)0.81 (0.62 to 1.07)0.15
 1992–1997137572.42 (2.05 to 2.86)0.97 (0.76 to 1.24)0.81

  • ↵* Sum of the expected deaths within the sex, disease course and age at onset strata may not equal the overall expected deaths (356) due to rounding.

  • ↵† SMR, standardised mortality ratio. Cohort entry defined as the date of first visit to a British Columbia multiple sclerosis clinic.

  • ↵‡ RMR, relative mortality ratio. The multivariable relative survival models included sex, clinical course and age at onset and were adjusted for age at cohort entry.

  • ↵§ 76 patients from the original cohort were excluded from these analyses because they were not successfully linked to Ministry of Health Registry and Premium Billing (RP&B) Files, which includes data and they only visited a British Columbia multiple sclerosis clinic once. Hence they were censored at their first clinic visit and contributed no follow-up time after cohort entry.

  • ↵ Relapsing onset cohort includes those who later became secondary progressive.

  • ↵** Standardised mortality ratios and relative mortality ratios for time period represent mortality risk within 10 years of follow-up.