Excess mortality emerges after 10 years in an inception cohort of early rheumatoid arthritis

Authors


Abstract

Objective

To investigate mortality rates, causes of death, time trends in mortality, prognostic factors for mortality, and the relationship between disease activity and mortality over a 23-year period in an inception cohort of rheumatoid arthritis (RA) patients.

Methods

A prospective inception cohort of RA patients diagnosed between January 1985 and October 2007 was followed for up to 23 years after diagnosis. Excess mortality was analyzed by comparing the observed mortality in the RA cohort with the expected mortality based on the general population of The Netherlands, matched for age, sex, and calendar year. Period analysis was used to examine time trends in survival across calendar time. Prognostic factors for mortality and the influence of the time-varying Disease Activity Score in 28 joints (DAS28) on mortality were analyzed using multivariable Cox proportional hazards models. Causes of death were analyzed.

Results

Of the 1,049 patients in the cohort, 207 patients died. Differences in observed and expected mortality emerged after 10 years of followup. No improvement in survival was noted over calendar time. Significant baseline predictors of survival were sex, age, rheumatoid factor, disability, and comorbidity. Higher levels of DAS28 over time, adjusted for age, were associated with lower survival rates, more so in men (hazard ratio [HR] 1.58, 95% confidence interval [95% CI] 1.35–1.85) than in women (HR 1.21, 95% CI 1.04–1.42).

Conclusion

Excess mortality in RA emerged after 10 years of disease duration. Absolute survival rates have not improved in the last 23 years and a trend toward a widening mortality gap between RA patients and the general population was visible. Higher disease activity levels contribute to premature death in RA patients.

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