Validation of Self‐Reported Rheumatoid Arthritis Using Medicare Claims: A Nationally Representative Longitudinal Study of Older Adults

Abstract

Objective To determine the validity of self‐reported physician diagnosis of rheumatoid arthritis (RA) using multiple gold‐standard measures based on Medicare claims in a nationally representative sample of older adults and to verify whether additional questions about taking medication and having seen a physician in the past two years for arthritis can improve the positive predictive value (PPV) and other measures of the validity of self‐reported RA. Methods A total of 3768 Medicare‐eligible respondents with and without incident self‐reported RA were identified from the 2004, 2008, and 2012 waves of the United States Health and Retirement Study. Self‐reported RA was validated using the following three claims‐based algorithms: 1) a single International Classification of Diseases, ninth edition, Clinical Modification claim for RA, 2) two or more claims no greater than 2 years apart, and 3) two or more claims with at least one diagnosis by a rheumatologist. Additional self‐report questions of medication use and having seen a doctor for arthritis in the past two years were validated against the same criteria. Results A total of 345 respondents self‐reported a physician diagnosis of RA. Across all three RA algorithms, the PPV of self‐report ranged from 0.05 to 0.16., the sensitivity ranged from 0.23 to 0.55., and the κ statistic ranged from 0.07 to 0.15. Additional self‐report data regarding arthritis care improved the PPV and other validity measures of self‐report; however, the values remained low. Conclusion Most older adults who self‐report RA do not have a Medicare claims history consistent with that diagnosis. Revisions to current self‐reported RA questions may yield more valid identification of RA in national health surveys.