The widening mortality gap between rheumatoid arthritis patients and the general population

Abstract

Objective: Overall mortality rates in the general US population have declined substantially over the last 4-5 decades, but it is unclear whether patients with rheumatoid arthritis (RA) have experienced the same improvements in survival. The purpose of this study was to determine the mortality trends among RA patients compared with those in the general population.

Methods: A population-based incidence cohort of RA patients was assembled, comprising all residents of Rochester, Minnesota ages > or = 18 years in whom RA was first diagnosed (according to the American College of Rheumatology [formerly, the American Rheumatism Association] 1987 criteria) between 1955 and 1995 and all residents of Olmsted County, Minnesota in whom RA was first diagnosed between 1995 and 2000. The patients were followed up longitudinally through their complete (inpatient and outpatient) medical records until death or January 1, 2007. Expected mortality was estimated from the National Center for Health Statistics life tables on the white population in Minnesota, using person-year methods. Poisson regression was used to model the observed mortality rates, adjusting for age, sex, and disease duration.

Results: A cohort of 822 RA patients (72% women, mean age at RA incidence 58 years) was followed up for a median of 11.7 years, during which 445 of the RA patients died. Between 1965 and 2005, the mortality rates across the calendar years for female and male RA patients were relatively constant at 2.4 and 2.5 per 100 person-years, respectively. In contrast, the expected mortality rate in the Minnesota white population decreased substantially over the same time period in both sexes. Mortality in the female general population declined from 1.0 per 100 person-years in 1965 to 0.2 per 100 person-years in 2000. Mortality in the male general population decreased from 1.2 per 100 person-years in 1965 to 0.3 per 100 person-years in 2000. Therefore, the difference between the observed and expected mortality rates increased in more recent years, resulting in a widening of the mortality gap.

Conclusion: Our findings show that RA patients have not experienced improvements in survival over the past 4 decades, despite dramatic improvements in the overall rates of mortality in the general US population. Further research into the causes of the widening gap in mortality between RA patients and the general population, and the influence of current therapeutic strategies on mortality, is needed in order to develop strategies to reduce the excess mortality observed in RA patients.