Household Income and Earnings Losses Among 6,396 Persons with Rheumatoid Arthritis

FREDERICK WOLFE, KALEB MICHAUD, HYON K. CHOI, and RHYS WILLIAMS

ABSTRACT.

Objective. Rheumatoid arthritis (RA) causes disability and reduced productivity. There are no large quantitative studies of earnings and productivity losses in patients with clinical RA, and no studies of household income losses. We describe methods for obtaining earnings and household income losses that are applicable to working as well as nonworking RA patients, and we perform such studies using these methods.

Methods. We estimated cross-sectional expected annual earnings and household income losses in 6,649 persons with RA from Current Populations Survey (CPS) and O*NET (Occupational Information Network) data, and we estimated expected household income and earnings losses based on demographic characteristics after adjustment to Medical Outcomes Study Short-Form 36 (SF-36) population norms (internal method). Workplace productivity was measured by the Work Limitations Questionnaire (WLQ).

Results. 27.9% of patients aged ≤ 65 years considered themselves disabled after 14.6 years of RA, and 8.8% received disability benefits. Annual earnings losses ranged between $2,319 and $3,407 by the CPS and internal method (preferred), with losses of 9.3% and 10.9%. A 0.25 difference in Health Assessment Questionnaire (HAQ) score was associated with a $1,095 difference in annual earnings. Productivity losses were 6% based on work limitations identified by the WLQ. Household income loss (percentage loss) including transfer payments was $6,287 (11.8%) for all patients, $4,247 (6.9%) for employed patients, and $7,374 (14.8%) for nonworking patients. Among nonworking nondisabled patients aged ≤ 65 years, income loss was 14.1%.

Conclusion. As measured by annual household income loss, the overall impact of RA is $6,287 (11.8%). Earnings and household income are dependent on functional status, education, age, ethnicity, and marital status. Income loss is predicted by the HAQ, HAQ-II, Modified HAQ, and SF-36. (J Rheumatol 2005;32:1875-83)

Key Indexing Terms:

RHEUMATOID ARTHRITIS
INDIRECT COSTS
PRODUCTIVITY
HOUSEHOLD INCOME
EARNINGS

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From the Arthritis Research Center Foundation, University of Kansas School of Medicine, Wichita, Kansas; Rheumatology Unit, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts; and Outcomes Research, Bristol-Myers Squibb, Princeton, New Jersey, USA.

The National Data Bank for Rheumatic Diseases has received grant support from Amgen, Aventis, Bristol Myers Squibb, Centocor, Pharmacia, and Pfizer pharmaceutical companies.

F. Wolfe, MD, Arthritis Research Center Foundation, University of Kansas School of Medicine; K. Michaud, MS, Arthritis Research Center Foundation, Center for Primary Care and Outcomes Research, Stanford University; H.K. Choi, MD, DrPH, Rheumatology Unit, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Department of Epidemiology, Harvard School of Public Health; R. Williams, ScD, Outcomes Research, Bristol-Myers Squibb.

Address correspondence to Dr. F. Wolfe, National Data Bank for Rheumatic Diseases, Arthritis Research Center Foundation, 1035 N. Emporia, Suite 230, Wichita, KS 67214. E-mail: fwolfe@arthritis-research.org

Accepted for publication May 2, 2005.

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