Study Finds Decline in Work Disability Due to Rheumatoid Arthritis
Rheumatoid arthritis (RA) is a chronic inflammatory disease affecting the joints and, in severe cases, vital organs. Marked by pain, fatigue and loss of dexterity and mobility, RA has been strongly associated with work disability in the United States. In previous studies of patients with advanced RA, 10 years in duration, the prevalence of work disability has been estimated at as high as 50 percent. However, most studies examining this costly effect of RA are well over a decade old. Since then, much has changed about the disease and the nature of work.
Prompted by these changes, researchers at Boston University speculated that the high prevalence of work disability among RA patients may have changed, and they set out to provide a comprehensive, up-to-date estimate. Featured in the April 2008 issue of Arthritis Care & Research, their data suggests that the employability outlook for men and women with advanced RA has improved since the mid-1980s.
Supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases, this study suggests a decline in the prevalence of RA work disability, particularly among patients with 10 years of disease duration, since the mid-1980s. As its authors note, there are several possible explanations for this, including declines in both the unemployment rate and the physical demands of jobs in the United States, as well as improvements in the treatment of RA. Among other notable findings, many cases of work disability were temporary, and many may have had little relationship to RA.
"Work disability among persons with RA in the U.S. is still a substantial problem," observes the study's lead author Saralynn Allaire, ScD. "However, our data in comparison with previous U.S. studies also suggest there has been some improvement over the past 15 to 20 years in those with longer-standing disease." As Allaire acknowledged, this study has limitations. "Because subjects with mild RA may not be fully represented in the NDB sample and may have less work disability, the actual RA work disability prevalence could be lower than we found. On the other hand, because NDB subjects have higher educational attainment and are more often white than the US population, and because these characteristics offer employment advantages, the actual RA work disability rate may be higher than we found."
Using the National Data Bank (NDB) longitudinal study of RA, researchers identified 5,384 subjects for analyses. All participants completed extensive surveys every 6 months between January 2002 and December 2005. Questions covered employment status at disease onset, discontinuation of work prior to traditional retirement age -- 65 years, cessation of work attributed to arthritis, and, for those currently employed, work characteristics. Participants also were asked to supply demographic data and the date of RA diagnosis. Functional limitation was determined by score on the Health Assessment Questionnaire (HAQ). Subgroups of patients were formed to assess prevalence of work disability by five-year intervals of disease duration. In addition, the annual incidence of work disability was calculated over three separate time periods: 2003, 2004, and 2005.
The mean age of the RA study population was 52 years. 82 percent of the subjects were women and 63 percent had more than a high school education. The mean disease duration was 14 years and the mean HAQ score was 1.0, indicating moderate functional limitation. 85 percent of subjects had been employed at disease onset and 56 percent were currently employed. Nearly three-quarters of these employed subjects worked full-time, 41 percent held professional or managerial jobs, and 16 percent were self-employed. Among subjects who were not employed, 43.5 percent were disabled; the remainder described themselves as either retired, full-time homemakers, or unemployed.
The prevalence of work cessation before age 65 increased with years of disease duration. This ranged from 23 percent among patients with relatively early RA -- 1 to 3 years, to 35 percent in those living with RA for a decade, and 51 percent in those with RA for at least a quarter century. The prevalence of arthritis-attributed work cessation also increased with disease duration but was somewhat lower, beginning with 14 percent in subjects with 1 to 3 years, increasing to 29 percent in subjects with 10 years, and culminating at 42 percent in those with RA for 25 years or more. The annual incidence of premature work cessation was 12 percent in 2003, 9 percent in 2004, and 9 percent in 2005. Incidence of work cessation directly attributed to arthritis was even lower, about 6 percent per year, and decreased slightly over the three years. 39 percent of the subjects who stopped working later returned to work over the course of the study period.