Same eyes, different doctors: differences in primary care physician referrals for diabetic retinopathy screening

To analyze eye care specialist referral patterns for the diabetic patients of primary care physicians.

In 1993, we conducted a census of primary care physicians to evaluate practice patterns relating to diabetes care in the state of Indiana. Using a logistic regression model and data from this census, we compared 1) physicians' odds of referring type II diabetic patients to an optometrist, as opposed to an ophthalmologist, with those of type I diabetic patients and 2) the referral odds ratios of type II to type I diabetic patients between metropolitan and nonmetropolitan counties.

Overall, 10% of the physicians in our study most often refer some patients to an optometrist. Physicians are more likely to refer their type II diabetic patients to an optometrist, as opposed to an ophthalmologist, than they are to refer type I diabetic patients, both before and after adjustment for covariates. Physicians who practice in metropolitan counties are 1.55 times more likely to refer their type II diabetic patients than their type I diabetic patients to an optometrist. In nonmetropolitan counties, physicians are 2.5 times more likely to refer their type II diabetic patients to an optometrist. The difference between metropolitan and nonmetropolitan physicians is significant (P = 0.027).

Some physicians mostly refer their diabetic patients to optometrists, instead of ophthalmologists, for eye examinations intended to discover early signs of diabetic eye disease. Type II diabetic patients are more likely to be referred to an optometrist, instead of an ophthalmologist, than are type I diabetic patients. In nonmetropolitan areas, the difference in referral patterns becomes even more marked.