ACCURACY OF CODING IN MEDICARE PART-B CLAIMS - CATARACT AS A CASE-STUDY

We studied the accuracy of Medicare part B coding for cataract extract ion to provide validation for research involving Medicare data. Hospit al and physician office records associated with a sample of 802 paid c laims for cataract surgery were reviewed. The sample was randomly sele cted from 118420 Medicare part B claims for cataract surgery submitted by physicians in an 11-state sample during the first quarter of 1988. Medical records were successfully obtained for 796 cataract surgery e pisodes (99.2%), of which 794 (99.7%) indicated that cataract extracti on had been performed. In the remaining two cases, cataract surgery wa s attempted but aborted. In 24 (3%) of the 794 cases, the surgical app roach (intracapsular or extracapsular) indicated in the operative note differed from that coded on the physician's bill. In all cases in whi ch the operative note indicated a secondary procedure performed at the time of surgery, the billing information was in agreement. We conclud e that, at least in the case of cataract surgery, the Medicare part B database is 99% accurate (95% confidence interval, +/-0.6%) for catara ct surgery having occurred and 96% accurate (95% confidence interval, +/-1.4%) in terms of surgical approach.