Brief Report: Rheumatoid Arthritis as the Underlying Cause of Death in Thirty-One Countries, 1987-2011: Trend Analysis of World Health Organization Mortality Database

Abstract

Objective: To examine trends in rheumatoid arthritis (RA) as an underlying cause of death (UCD) in 31 countries across the world from 1987 to 2011.

Methods: Data on mortality and population were collected from the World Health Organization mortality database and from the United Nations Population Prospects database. Age-standardized mortality rates (ASMRs) were calculated by means of direct standardization. We applied joinpoint regression analysis to identify trends. Between-country disparities were examined using between-country variance and the Gini coefficient. Due to low numbers of deaths, we smoothed the ASMRs using a 3-year moving average. Changes in the number of RA deaths between 1987 and 2011 were decomposed using 2 counterfactual scenarios.

Results: The absolute number of deaths with RA registered as the UCD decreased from 9,281 (0.12% of all-cause deaths) in 1987 to 8,428 (0.09% of all-cause deaths) in 2011. The mean ASMR decreased from 7.1 million person-years in 1987-1989 to 3.7 million person-years in 2009-2011 (48.2% reduction). A reduction of ≥25% in the ASMR occurred in 21 countries, while a corresponding increase was observed in 3 countries. There was a persistent reduction in RA mortality, and on average, the ASMR declined by 3.0% per year. The absolute and relative between-country disparities decreased during the study period.

Conclusion: The rates of mortality attributable to RA have declined globally. However, we observed substantial between-country disparities in RA mortality, although these disparities decreased over time. Population aging combined with a decline in RA mortality may lead to an increase in the economic burden of disease that should be taken into consideration in policy-making.