An assessment of the annual and long-term direct costs of rheumatoid arthritis: the impact of poor function and functional decline.

OBJECTIVE: To describe the distribution of direct medical care costs of rheumatoid arthritis (RA) over 1-year and 11-year periods, and to evaluate the impact of poor function and functional decline on direct costs.
METHODS: The present study uses data from the University of California, San Francisco, RA Panel Study in which 1,156 persons with RA have been followed up for as long as 15 years through annual structured interviews and periodic updates on severity from rheumatologists. We present annual direct medical care cost data for the years 1995 and 1996 and estimates of cumulative costs for the period 1986-1996 for the 272 persons followed up continuously for this period.
RESULTS: Medical care costs for RA averaged $5,919 a year from a societal perspective; persons with RA incur another $2,582 in medical care costs for non-RA reasons. Of the RA total costs, hospital admissions account for more than half. Costs are highly skewed, with the costs in the 90th, 95th, and 100th percentiles totaling $8,209, $31,059, and $85,469 a year, respectively. Cumulative costs for the period 1986-1996 averaged $57,201, with cumulative costs in the 90th, 95th, and 100th percentiles totaling $114,844, $142,563, and $191,540, respectively. Persons with RA in the worst quartile of function experienced total annual direct costs that were 2.55 times as high and total hospital costs that were 6.97 times as high as those in the best (e.g., the first) quartile. Poor baseline functional status and declining functional status had similar, large effects on cumulative medical care costs.
CONCLUSION: Medical care costs for RA over 1 year and 1 decade are highly skewed. Persons with RA with poor and declining function experience much higher costs of care.