Can Ophthalmologists Achieve Better Blood Glucose Control in Their Diabetic Patients?

Abstract

Ophthalmology is generally considered to be limited to disorders of the eye and its adnexa. Diabetes mellitus, however, is a systemicdisease thatweencounter frequently in our ophthalmic practices because of its ocular complications, especially diabetic retinopathy. When, after years of controversy, 2 seminal randomized clinical trials, the Diabetes Control andComplications Trial (DCCT)1 and theUKProspectiveDiabetes Study (UKPDS),2 clearly found that near-normal bloodglucosecontrol significantly slows thedevelopmentand progressionof diabetic retinopathy inpatientswith type 1 and type 2 diabetes, with a marked effect on the protection of vision, ophthalmologists were offered an important opportunity toadviseourdiabeticpatientson themanagementof their systemicdisease.Consequently, theDiabeticRetinopathyClinical ResearchNetwork (DRCR.net), a large groupof collaborating centers funded by theNational Eye Institute, conducted a randomizedclinical trial to investigatewhethermeasuringhemoglobinA1c (HbA1c) in the ophthalmology clinic, counseling patients on the relevanceof goodbloodglucose control toprevent retinopathy, and providing personalized risk assessments toeachpatient could significantly improveglucose control in patients during a 1-year period. The negative results of thisprojectarepresented inthis issueofJAMAOphthalmology.3 An earlier study4 indicated that only approximately half of adults with diabetes knew their HbA1c levels, the association of those levels with blood glucose control, and the level (≤7.0%) that is recommended to minimize the risk of developing retinopathy or other microvascular complications of diabetes. A substantially smaller number (24%) have HbA1c values less than or equal to that level.4 The present investigation had a complex protocol. Forty-two clinical centers and 1746 patients participated. Participating clinics comprised 34 that randomized patients by center and 8 that randomized by physician within the center. Patients, who had to have a recent HbA1c value of 7.5% or higher and meet several other criteria to be eligible, were divided into 2 groups. The larger group (990 patients) had multiple (up to 4) ophthalmologic clinic visits during the year, whereas the smaller group (756 patients) was seen only twice, at the beginning and end of the study. Each of these 2 groups was then randomized to standard care, including regular ophthalmic examination but no supplemental information, or to intervention, including measurement of HbA1c and blood pressure, an eye examination, and photographs taken in the ophthalmology clinic at each visit. This was followed by a personalized risk assessment for the development or progression of retinopathy and nephropathy based on past and present HbA1c levels. Patients were tested on their understanding of the importance of good diabetes control, and they received immediate feedback if this understanding was insufficient. The study was planned for 2 years but was stopped after 1 year when it became clear that no significant differences in HbA1c levels were developing between the standard care and intervention groups in either the annual or the more frequent follow-up cohorts. In addition, in none of these groups was there a significant decrease in HbA1c level during the follow-up period. The authors of this study do not speculate why their interventions failed, but they suggest several possible additional approaches, all of which involve interventions performed by the ophthalmologist and his or her associates. I suggest that none of these are likely to be successful. Diabetesmanagement is an extremely challenging problem that involves intensive, personal interactions of medical personnel with patients from a variety of educational, cultural, and socioeconomic backgrounds to achieve adherence of these patients to a strict medication regimen and an array of lifestyle changes that involve diet, exercise, and frequent monitoring of bloodglucoseperformedathome through frequent andunpleasant fingerstick tests. Several recent efforts in the United States to enable patients with diabetes to better control their blood glucose levels have met with only limited success, including recommendationsby theUSDepartmentofHealthand Human Services for community blood glucose control monitoringprogramsand for evaluating the efficacyof psychological interventions. Those programs that were successful in improving blood glucosecontrol indiabeticpatientshave involved intensivepersonal involvement with patients during a substantial period. Patients in the DCCT intensive treatment cohort maintained a mean HbA1c value of slightly more than 7% during a mean follow-up of 6.5 years,with ameanblood glucose value of 155 mg/dL (to convert tomillimoles per liter,multiply by0.0555).1 By contrast, patients in the conventional care cohort had a meanHbA1c value of 9%andameanbloodglucose level of 231 mg/dL. The DCCT protocol required monthly clinic visits by each patient assigned to the intensive therapy regimen, with weekly telephonecalls fromthe studycoordinator.At the conclusionof theDCCT, the follow-up study, theEpidemiologyof Diabetes Interventions and Complications (EDIC), found that by 10 years after the end of the DCCT the mean HbA1c values inpatients inboththeoriginal intensiveandconventional treatmentgroupswereapproximately8%.5Similarly, in theUKPDS, between-groupdifferences inHbA1cvaluesdisappearedwithin 1 year of the conclusion of the study.6 Comparison of the DCCT and UKPDS results with the presentDRCR.net results indicates that a successful intervention to improve glycemic control in diabetic patients must be Related article page 888 Effect of Personalized Diabetes Risk Assessments on Glycemic Control Original Investigation Research