Coding of glaucoma for patients with uveitis in the medicare database

To investigate possible causes for, and implications of, variations in coding of glaucoma for patients with uveitis in the Medicare database.

We identified 6,391 patients coded with one of several ICD-9 codes designating a form of uveitis from a 5% sample of the 1999 Medicare database. The proportion of patients with uveitis codes who also had codes for uveitic glaucoma, primary open-angle glaucoma (POAG), or unspecified open-angle glaucoma (OAG) were determined. The proportion with codes for argon laser trabeculoplasty (ALT), trabeculectomy, visual field examinations, fundus photographs, and gonioscopy were calculated in three groups: patients with both uveitis and uveitic glaucoma; those with both uveitis and POAG; and those with both uveitis and unspecified open-angle glaucoma. Summaries of the total allowed reimbursement related to eye visits and to eye codes were determined.

Of the 6,391 patients with uveitis who were studied, 1,260 (19.7%) also had the code for POAG; 412 (6.4%) had the code for OAG; and 117 (1.8%) had the code for uveitic glaucoma. Visual field testing was less common among patients with uveitic glaucoma (37%) than among those with POAG/uveitis (46%) or OAG/uveitis (44%) (P < 0.001). There were no statistically significant differences among the three groups in the amount of total reimbursement related to eye services or eye codes.

The code for POAG appears to be used in lieu of uveitic glaucoma in many cases. Discrepancies are probably not influenced by expected reimbursements, as much as by a lack of understanding about the available ICD-9 codes.