Could accelerated aging explain the excess mortality in patients with seropositive rheumatoid arthritis?

Abstract

Objective: To determine whether the mortality pattern in patients with seropositive rheumatoid arthritis (RA) is consistent with the concept of accelerated aging, by comparing the observed mortality rates in patients with RA with the age-accelerated mortality rates from the general population.

Methods: A population-based inception cohort of patients with seropositive RA (according to the American College of Rheumatology 1987 criteria) was assembled and followed up for vital status until July 1, 2008. The expected mortality rate was obtained by applying the death rates from the general population to the age, sex, and calendar year distribution of the RA population. The observed mortality was estimated using Kaplan-Meier methods. Acceleration factors for the expected mortality were estimated in accelerated failure time models.

Results: A total of 755 patients with seropositive RA (mean age 55.6 years, 69% women) were followed up for a mean of 12.5 years, during which 315 patients died. The expected median survival was age 82.4 years, whereas the median survival of the RA patients was age 76.7 years. Results of statistical modeling suggested that, in terms of mortality rates, patients with RA were effectively 2 years older than actual age at RA incidence, and thereafter the patients underwent 11.4 effective years of aging for each 10 years of calendar time.

Conclusion: The overall observed mortality experience of patients with seropositive RA is consistent with the hypothesis of accelerated aging. The causes of accelerated aging in RA deserve further investigation.

Figure 1

Overall survival of 755 seropositive RA patients vs. age. Observed, expected and fitted (using the full model) curves are shown.