Agreement between Self-Report and Medicare Claims Diagnostic Codes for Ocular Diseases and Eye Care Service Use

Abstract

Abstract: : Purpose: To evaluate the relationship between self-report of ocular or systemic diseases and eye care service use in fee-for-service Medicare beneficiaries with Medicare claims diagnostic codes. Methods: In the Vision Services Study, a random sample of Medicare fee-for-service beneficiaries in Los Angeles County was interviewed over the telephone on their use of eye care services and their medical and ocular history in the preceding year. The responses of the subjects were compared to the diagnostic codes from Medicare claims data from 1997. Descriptive and kappa statistics were used. Results: 236 subjects completed the survey. Information from the Medicare claims records was available on 216 subjects. 34 (15.7%) subjects had more than 2 chronic illnesses and 91 (42.1%) were older than 75 years of age. The agreement between subject's self-report of a condition and diagnostic claim depends on the condition and the age of the subject. Table: Kappa statistics between self-report of ocular or systemic disease and Medicare diagnostic claims codes.  

Of the 91 subjects who had not seen an eye doctor in the past 12 months according to Medicare claims data, 41.8% reported that they had (Κ= 0.55). There was fair agreement that the eye doctor was an ophthalmologist (Κ= 0.28) and slight agreement beyond chance that the eye doctor was an optometrist (Κ=0.18). The worst agreement was for visual field testing where 101 subjects said they had a visual field on the interview and there was no indication of a visual field having been billed in the Medicare claims data (Κ= 0.06). Conclusion: Agreement between self-report and Medicare claims data depends not only on the specific condition or service but also on the age and health of the subject. Older subjects were more aware that they had cataracts or glaucoma, and subjects with 2 or more chronic diseases were more likely to report glaucoma, but not cataracts. The agreement ranged from slightly better than chance to substantial agreement.

Keywords: 351 clinical (human) or epidemiologic studies: health care delivery/economics/manpower • 338 cataract • 387 diabetes