Patients with newly diagnosed but still untreated rheumatoid arthritis increase their use of sick leave and disability pension benefits, judging from findings from a Swedish study. Initiation of standard treatment halted but did not reverse this development.
These findings, reported in the August issue of Annals of the Rheumatic Diseases, suggest that the ability to work may be an important clinical measure when evaluating the needs of patients with RA, and may indicate the need for earlier intervention.
Lost productivity figures large among the indirect costs of rheumatoid arthritis. Yet, the only evidence of patients’ ability to work with RA comes from studies that were small or included limited or no history of sick leave. Some limited data come in the form of secondary findings from trials of RA treatments.
To try to fill in the gaps, Martin Neovius, Ph.D., of the Karolinska Institute in Stockholm, and his colleagues in the Anti-Rheumatic Therapies in Sweden (ARTIS) Study Group investigated the number of days of sick leave and disability taken by patients with RA – both before and after initiation of standard therapies (Ann. Rheum. Dis. 2011;70:1407-14).
First, they identified patients aged 19-60 years who were diagnosed with RA between 1999 and 2007. Data on when treatment was initiated came from the Swedish Rheumatology Quality Register. Next, they used each patient’s personal identification number to retrieve data on sick leave and disability pension from the Social Insurance Office database.
The researchers divided the patients into four cohorts: 2,796 patients who received nonbiologic disease-modifying anti-rheumatic drug (DMARD) monotherapy; 973 patients who received nonbiologic DMARD combination therapy; 1,600 patients with RA for less than 5 years who received biologic therapy; and 4,787 patients who received biologic agents regardless of RA duration.
The prevalence of sick leave and disability pension was lowest before the start of DMARD therapy, the researchers found. Specifically, 10% and 12% of patients received disability pension benefits during the year before starting DMARD monotherapy and combination therapy, respectively, and 43% of patients received benefits before starting biologic treatment.
The mean number of days of disability pension per year was 25 during the year before the start of DMARD monotherapy, 27 before the start of DMARD combination therapy, and 111 for biologic therapy. However, fewer days of sick leave were taken in the year before the start of biologic agents and DMARD monotherapy (mean 79 and 54 days, respectively) than before the start of DMARD combination therapy (105 days).
The mean number of monthly days of sick leave and disability pension increased in all cohorts in the year before treatment and peaked at 1 month after treatment began, the researchers said. After that first month following treatment, sick leave stabilized below the peak level, but disability pensions increased.
"We made a series of important observations," the researchers said. "One, irrespective of treatment type, initiators had on average a long history of gradual deterioration in work ability, although, as expected, the level of days off work was higher among patients selected for biological therapy than those starting a first nonbiological DMARD monotherapy. Two, irrespective of treatment type, patients selected for these treatments were characterized by a breakpoint in the deteriorating work ability following treatment start." The third lesson was that patients continued to use disability despite their increased ability to work, the authors reported.
Intensive treatment halted but did not reverse the deterioration of work ability, the researchers said. After initiation of treatment with biologic agents, the annual level of sick leave and disability pension was close to 200 days a year out of a maximum of 365, and more than 150 days for those who started on combination DMARD treatment.
"Given the increase observed already before treatment start, there is an obvious need to identify patients at risk of work ability deterioration much earlier than currently, and potentially break the development," the researchers said.
The ARTIS Study Group conducts scientific analyses using data from the Swedish Biologics Register ARTIS run by the Swedish Society for Rheumatology. For the maintenance of this register, the Swedish Society for Rheumatology has received funding, independent of the conduct of these scientific analyses, from Abbott Laboratories, BMS, Roche, Schering-Plough, UCB, and Wyeth.