Vision loss among diabetics in a group model health maintenance organization (HMO)

Vision loss among diabetics in a group model health maintenance organization (HMO)

Vision Loss Among Diabetics in a Group Model Health Maintenance Organization (HMO) DONALD S. FONG, MD, MPH, MOHKTAR SHARZA, BS, WANSU CHEN, MS, JOHN F...

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Vision Loss Among Diabetics in a Group Model Health Maintenance Organization (HMO) DONALD S. FONG, MD, MPH, MOHKTAR SHARZA, BS, WANSU CHEN, MS, JOHN F. PASCHAL, MD, MPH, REGINALD G. ARIYASU, MD, PHD, AND PAUL P. LEE, MD, JD

● PURPOSE:

To report the management of diabetic retinopathy in one group model health maintenance organization and assess the quality of care. ● METHODS: Cross-sectional study. A chart review of 1200 randomly identified patients with diabetes mellitus, continuously enrolled for 3 years in Kaiser Permanente (KP) Southern California, the largest provider of managed care in Southern California, was performed. A total of 1047 patients were included in the analyses. Patient characteristics as well as information from the last eye examination were abstracted. Charts from patients with visual acuity less than 20/200 in their better eye (legal blindness) were selected for extensive chart review to determine the cause of visual loss and the antecedent process of care. T tests or the Wilcoxon rank sum test was used to compare continuous variables. The ␹2 test or the Fisher exact test was used to compare categorical variables. All analyses were performed on the Statistical Analyses System (SAS Institute, North Carolina). ● RESULTS: Our study population of 1047 diabetic patients was 51.7% male, had a mean age of 60.4 years, a mean duration of diabetes of 9.6 years, and a mean hemoglobin A1c of 8.3%. During the study period, 77.5% of patients received a screening eye examination with examination by an ophthalmologist, an optometrist, or review of a retinal photograph. Of those with a visual acuity assessment (n ⴝ 687, 65.6% of 1047), 1.5% had visual acuity of 20/200 or worse (legally blind) in the better eye, while 8.2% had this level of visual acuity in Accepted for publication May 29, 2001. From the Department of Ophthalmology, Southern California Permanente Medical Group, Baldwin Park, CA (D.S.F., M.S., J.F.P., R.G.A., P.P.L.); Department of Ophthalmology, UCLA School of Medicine, Los Angeles, CA (D.S.F., J.F.P., R.G.A.); Research and Evaluation, Southern California Permanente Medical Group, Pasadena, CA (W.C.); Department of Ophthalmology, Duke University, Durham, NC (P.P.L.). Address reprint requests to: Donald S. Fong, MD, MPH, Department of Ophthalmology, Kaiser Permanente Medical Center, 1011 Baldwin Park Boulevard, Baldwin Park, CA 91706; fax: 626-851-6106; e-mail: [email protected]

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the worse eye. Of eyes with new onset clinically significant macular edema and visual acuity < 20/40, 40% had documentation of focal laser performed within 1 month of diagnosis. Of eyes with vitreous hemorrhage and visual acuity < 20/40, 50% had documentation of vitrectomy. Among eyes that had vitrectomy, over 80% had this procedure within 1 year of diagnosis of vitreous hemorrhage. ● CONCLUSIONS: The current report is the largest study of diabetic retinopathy outcomes among patients enrolled in a prepaid health plan. Further research is necessary to investigate the impact of managed care on health outcomes. (Am J Ophthalmol 2002;133:236 –241. © 2002 by Elsevier Science Inc. All rights reserved.)

C

ONCERN HAS BEEN RAISED ABOUT THE QUALITY OF

care for patients enrolled in managed care. The concern relates to possible under-referral to specialists and under-treatment of disease. Previous investigations have reported a 50% reduction in the rate of cataract surgery in managed care vs fee-for-service plans.1 However, others have suggested that patients in managed care plans may receive better care because there is better coordination of care, increased use of preventive services, and the availability of specialists. In the Medical Outcome Study, the self-reported rate of using ophthalmic services within the previous 6 months among patients with diabetes screening for diabetic retinopathy was found to be similar between prepaid and fee-for-service health plans.2 In the current study, we investigated the visual outcomes of diabetic retinopathy management in one Southern California group model health maintenance organization (HMO) from a review of the medical records. The current study is a cross-sectional chart review of 1200 patients over 18 years of age, who were randomly identified from the diabetes case identification database. To help physicians manage diabetes, Kaiser Permanente

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Southern California maintains a Diabetes Case Identification Database which includes all patients who meet the following criteria: Patients with 250.xx ICD-9 hospital diagnosis, who received a prescription for insulin or oral hypoglycemic, had a laboratory measurement of HgA1c ⬎ 6.7 or Fructosamine ⬎ 280 are included. The sensitivity of the database is thought to be greater than 93% (personal communication from Kaiser Permanente Department of Research and Evaluation). The database contains 108,724 patients. Of the 1200 patients randomly identified, 143 (12%) patients were excluded from the study and a total of 1047 were included for chart review. Of those who were excluded for study, 9.3% (112) were deceased, 1.3% (16) did not have diabetes, 0.42% (5) had gestational diabetes, 0.25% (3) resided outside our study area, 0.25% (3) lived in a nursing home, and 0.16% (2) were under the age of 18. The chart was either missing or incomplete in 8.4% (12).

METHODS WE STUDIED MANAGEMENT OF DIABETIC RETINOPATHY IN

Kaiser Permanente (KP) Southern California. KP, a group model health maintenance organization, is the largest provider of managed care in Southern California and insures approximately 23% of insured patients. Charts were reviewed for information recorded during the 2 year study period (January 1, 1996 and December 31,1997). The following was recorded: current age, last name, gender, age of onset of diabetes, eye care information (date of last examination, visual acuity, tonometry, and grade of diabetic retinopathy), primary care information (glycosylated hemoglobin, blood pressure, angiotensin converting enzyme inhibitor use, serum creatinine, and blood urea nitrogen level). Charts from patients with visual acuity less than 20/200 in their better eye (legal blindness) were selected for more extensive chart review to determine the cause of visual loss and the utilization of laser and vitrectomy. Standard descriptive statistics were used to describe the visual acuity distribution. T tests or the Wilcoxon rank sum test was used to compare continuous variables. The ␹2 test or the Fisher exact test was used to compare categorical variables. All analyses were performed on the Statistical Analyses System (SAS Institute, North Carolina)

RESULTS OUR STUDY POPULATION WAS 51.7% MALE, HAD A MEAN

age of 60.4 years, a mean duration of diabetes of 9.6 years, and a mean hemoglobin A1c of 8.3% (Table 1). During the study period, 77.5% of patients received a screening VOL. 133, NO. 2

TABLE 1. Description of the Population (N ⫽ 1,047), N (%) Unless Specified Male Mean age ⫾ SE Median age (range) Hispanic surname Insulin use Diabetes drug use Mean duration of diabetes ⫾ SE Median duration (range) Mean HgA1c ⫾ SE Median HbA1c (range) Diastolic ⬎ 90 Systolic ⬎ 160 If diastolic ⬎90 or systolic ⬎ 160, was patient on ACE inhibitor Yes No Proteinuria Mean cholesterol ⫾ SE Median cholesterol (range) Eye visit With ophthalmologist With optometrist With photos Visit with a dietician Visit with a diabetes educator Visit with a podiatrist

541 (51.7%) 60.4 ⫾ 0.4 61.1 (21.7–92.2) 265 (25.3%) 335 (32.0%) 774 (73.9%) 9.6 ⫾ 0.3 7.4 (0.0–50.3) 8.3 ⫾ 0.08 7.7 (4.7–18.5) 97 (9.8%) 115 (11.7%)

98 (58.0%) 71 (42.0%) 206 (19.7%) 207.4 ⫾ 1.6 202.0 (99.0–530.0) 389 (48.0%) 263 (32.4%) 159 (19.6%) 584 (55.8%) 679 (64.9%) 322 (30.8%)

TABLE 2. Distribution of Visual Acuity in the Better and Worse Eye

ⱖ20/40 ⬍20/40 and ⬎20/200 ⬎20/200

Better Eye (N ⫽ 687)

Worse Eye (N ⫽ 687)

631 (91.8%) 46 (6.7%) 10 (1.5%)

524 (76.3%) 107 (15.6%) 56 (8.2%)

eye examination with examination by an ophthalmologist, an optometrist, or review of a retinal photograph. Table 2 describes the mean visual acuity in the better and worse eye. In 1.5% of patients, the visual acuity in the better eye was 20/200 or worse (legally blind), while 8.2% of patients had this level of visual acuity in the worse eye. Among eyes with 20/200 visual acuity or worse, 48.9% (23/47) did not have proliferative diabetic retinopathy documented (Table 3). Patient characteristics were compared among patients with and without visual acuity of 20/40 or better in the better eye (Table 4). Patients with visual acuity ⬍ 20/40 in the better eye were more likely to be older (mean: 70.6 vs 60.5, P ⬍ .001), had a longer duration of diabetes (mean:

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TABLE 3. (a) Distribution of Visual Acuity in The Better Eye by Retinopathy Level; (b) Distribution of Visual Acuity in the Worse Eye by Retinopathy Level Visual Acuity (a) Level of Retinopathy

ⱖ20/40

⬍20/40 & ⬎20/200

ⱕ20/200

Total

No/minimal retinopathy Background/mild nonproliferative retinopathy Moderate/severe nonproliferative Proliferative retinopathy

355 (95.2%) 113 (91.9%) 12 (85.7%) 28 (65.1%)

16 (4.3%) 10 (8.1%) 2 (14.3%) 9 (20.9%)

2 (0.5%) 0 (0.0%) 0 (0.0%) 6 (14.0%)

373 123 14 43

Visual Acuity (b) Level of Retinopathy

ⱖ20/40

⬍20/40 & ⬎20/200

ⱕ20/200

Total

No/minimal Background/mild nonproliferative retinopathy Moderate/severe nonproliferative Proliferative retinopathy No view

302 (82.5%) 96 (76.8%) 6 (50.0%) 13 (28.9%) 0 (0.0%)

49 (13.4%) 24 (19.2%) 5 (41.7%) 14 (31.1%) 0 (0.0%)

15 (4.1%) 5 (4%) 1 (8.3%) 18 (40.0%) 1 (100.0%)

366 125 12 45 1

17.6 vs 9.7, P ⬍ .001), and were on a medication other than insulin to treat their diabetes (74.2% vs 53.6, P ⬍ .001). The mean level of HgA1c was similar in both groups. Similar results were found in the comparison between patients with and without visual acuity of 20/40 in the worse eye. Compared with patients with visual acuity of ⬎ 20/200 in the better eye, those with ⱕ 20/200 in the better eye were similar except for having lower HgA1c (Table 5). The same analysis for visual acuity in the worse eye showed that those with 20/200 or worse were older (mean 68.4 vs 61.8 years, P ⬍ .001), and had longer duration of diabetes (mean 12.3 vs 7.9 years, P ⬍ .001). Glycosylated hemoglobin levels were similar. We also decided to look at the use of laser photocoagulation and vitrectomy among our population (Table 6). Among patients with ⬍ 20/40 visual acuity in either eye and proliferative diabetic retinopathy, over 70% had documentation of panretinal photocoagulation. Of eyes with clinically significant macular edema, 40% had documentation of focal laser performed within one month. Of eyes with vitreous hemorrhage, approximately 50% had documentation of vitrectomy. Among eyes that had vitrectomy, over 80% had this procedure within 1 year of diagnosis of vitreous hemorrhage. The causes of visual loss among eyes with visual acuity ⱕ 20/200 blindness are listed in Table 7. The most common cause was proliferative diabetic retinopathy and vitreous hemorrhage, followed by macular edema. In the other category, there was one eye each with visual loss from open angle glaucoma, trauma before onset of diabetes, and two with macular hole. The etiology in one eye could not be determined. 238

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DISCUSSION EVALUATING EYE CARE PROVIDED BY MANAGED CARE OR-

ganizations is important because many people are enrolled in these programs. To protect the health of these patients, it is our responsibility to evaluate their care and advocate for them. We chose to study diabetes eye care because intervention has been shown to prevent blindness and also because it has been identified by the National Committee on Quality Assurance (NCQA) as a HEDIS (Health plan Employer Data and Information Set) measure. While included in HEDIS, the frequency of eye examinations is only a “process measure” and therefore only an indirect indicator of quality. The prevalence of vision loss in our study was low. Only 1.5% of patients had visual acuity of 20/200 or worse in the better eye and 91.8% had visual acuity of ⱖ 20/40. This low frequency is interesting given the multiethnic makeup of our study population; 25.3% of our study population had Hispanic surnames. Previous population based studies of visual acuity and diabetic retinopathy were based on persons of northern European ancestry. The Wisconsin Epidemiologic Study of Diabetic Retinopathy (WESDR) investigated visual impairment among diagnosed diabetics.3 In the WESDR, among patients with earlier age of onset (patients with insulin dependent diabetes mellitus), 1.4% had moderate visual impairment (visual acuity in the better eye of 20/80 to 20/160) and 3.6% were legally blind (20/200 or worse). In patients with older age of onset (patients with noninsulin dependent diabetes mellitus), 3.0% had moderate visual impairment and 1.6% were legally blind. Because African Americans and HispanicAmericans may have higher rates of retinopathy prevaOF

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TABLE 4. Comparison of Patient Characteristics Between Patients With the Better Eye Visual Acuity ⱖ20/40 and ⬍20/40 ⱖ20/40

N Male Mean age ⫾ SE Median age (range) Hispanic surname Insulin use Diabetes drug use Mean duration of diabetes ⫾ SE Median duration (range) Mean HgA1c ⫾ SE Median HbA1c (range) Diastolic ⬎ 90 Systolic ⬎ 160 If diastolic ⬎90 or systolic ⬎ 160, was patient on ACE inhibitor Yes No Proteinuria Mean cholesterol ⫾ SE Median cholesterol (range) Eye visit With ophthalmologist With optometrist With photos Visit with a dietician Visit with a diabetes educator Visit with podiatry

⬍20/40

631 324 (51.3%) 60.5 ⫾ 0.5 61.6 (21.7–88.2) 152 (24.1%) 210 (33.3%) 468 (74.2%) N ⫽ 602 9.7 ⫾ 0.3 7.8 (0.0–50.3) N ⫽ 546 8.1 ⫾ 0.09 7.7 (4.9–15.8) 59 (9.8%) (N ⫽ 605) 75 (12.4%) (N ⫽ 556)

56 29 (51.8%) 70.6 ⫾ 1.3 70.9 (44.3–92.2) 7 (12.5%) 25 (44.6%) 30 (53.6%) N ⫽ 52 17.6 ⫾ 1.5 16.6 (0.4–38.2) N ⫽ 50 7.8 ⫾ 0.3 7.2 (5.2–13.3) 4 (7.3%) (N ⫽ 55) 7 (12.7%) (N ⫽ 55)

N ⫽ 105 63 (60.0%) 42 (40.0%) 111 (17.6%) N ⫽ 496 206.7 ⫾ 2.1 202.0 (99.0–530.0) N ⫽ 630 339 (53.8%) 260 (41.3%) 31 (4.9%) 374 (59.3%) 415 (65.8%) 207 (32.8%)

N ⫽ 10 5 (50.0%) 5 (50.0%) 16 (28.6%) N ⫽ 42 195.6 ⫾ 5.8 198.5 (114.0–294.0) N ⫽ 55 50 (90.9%) 3 (5.5%) 2 (3.6%) 35 (62.5%) 39 (69.6%) 29 (51.8%)

P

0.950 ⬍0.001a ⬍0.001b 0.049 0.086 ⬍0.001 ⬍0.001a ⬍0.001b 0.340a 0.194b 0.549 0.943

0.738*

0.042 0.131a 0.151b ⬍0.001

0.637 0.557 0.004

*For categorical variables, P values were based on the chi-square test (not marked by *) or the Fisher exact test. a For continuous variables, P values were based on the t test. b For continuous variables, P values were based on the Wilcoxon rank-sum test.

lence and progression,4,5 the current study provides important information on vision loss in a multiethnic population. In the current study, the use of laser photocoagulation and vitrectomy also was low (Table 6). For proliferative diabetic retinopathy (PDR), between 73%–75% of eyes with PDR had documentation of panretinal photocoagulation. Although the frequency may seem low, it appears to correspond to the rate identified through a survey of ophthalmologists.6 In this survey of general ophthalmologists and retina specialists, 73% of retina specialists recommended immediate treatment. Among general ophthalmologists, 45% recommended treatment and 40% recommended referral to a retina specialist. The remainder of physicians chose follow-up within 2 to 3 months. VOL. 133, NO. 2

This low rate of intervention also may be due to poor documentation. Physicians practicing in a group model HMO are not directly compensated for the procedures they perform and may document less completely. Another explanation may be the definition used in the study. Once a patient has been diagnosed with proliferative diabetic retinopathy, she or he retains this diagnosis even when they have been treated with pan retinal laser photocoagulation. Among patients with clinically significant macular edema, 40% had documentation of focal laser photocoagulation. Focal laser treatment has been shown to be effective in reducing moderate visual loss, but the time interval between diagnosis and treatment has not been determined. The current number, again, may represent an

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TABLE 5. Comparison of Patient Characteristics Between Patients With the Better Eye Visual Acuity ⬎20/200 and ⱕ20/200 ⬎20/200

N Male Mean age ⫾ SE Median age (range) Hispanic last names Insulin use Diabetes drug use Mean duration of diabetes ⫾ SE Median duration (range) Mean HgA1c ⫾ SE Median HbA1c (range) Diastolic ⬎ 90 Systolic ⬎ 160 If diastolic ⬎90 or systolic ⬎ 160, was patient on ACE inhibitor Yes No Proteinuria Mean cholesterol ⫾ SE Median cholesterol (range) Eye visit With ophthalmologist With optometrist With photos Eye visit/note from dietician Eye visit/note from diabetes educator Eye visit/note from podiatry

ⱕ20/200

677 348 (51.4%) 61.3 ⫾ 0.4 62.2 (21.7–92.2) 158 (23.3%) 229 (33.8%) 494 (73.0%) N ⫽ 644 10.3 ⫾ 0.3 8.1 (0.0–50.3) N ⫽ 588 8.1 ⫾ 0.08 7.6 (4.9–15.8) 62 (9.5%) (N ⫽ 651) 81 (12.4%) (N ⫽ 651)

N ⫽ 114 68 (59.7%) 46 (40.3%) 126 (18.6%) N ⫽ 532 206.0 ⫾ 2.0 201.5 (99.0–530.0) N ⫽ 675 380 (56.3%) 262 (38.8%) 33 (4.9%) 402 (59.4%) 447 (66.0%) 231 (34.1%)

10 5 (50.0%) 67.4 ⫾ 3.3 68.5 (48.5–82.9) 1 (10.0%) 6 (60.0%) 4 (40.0%) N ⫽ 10 15.1 ⫾ 3.3 13.2 (3.9–32.7) N⫽8 6.8 ⫾ 0.3 6.8 (5.2–7.7) 1 (11.1%) (N ⫽ 9) 1 (11.1%) (N ⫽ 9)

N⫽1 0 (0.0%) 1 (100.0%) 1 (10.0%) N⫽6 189.3 ⫾ 16.8 199.5 (114.0–231.0) N ⫽ 10 9 (90.0%) 1 (10.0%) 0 (0.0%) 7 (70.0%) 7 (70.0%) 5 (50.0%)

P

1.000* 0.095a 0.090b 0.467* 0.099* 0.030* 0.072a 0.093b 0.003a 0.061b 0.597* 1.000*

0.409*

0.698* 0.373a 0.572b 0.142*

0.747* 1.000* 0.324*

*For categorical variables, P values were based on the chi-square test (not marked by *) or the Fisher exact test. a For continuous variables, P values were based on the t test. b For continuous variables, P values were based on the Wilcoxon rank-sum test.

cross-sectional design of our study. High glycosylated hemoglobin likely predicts future visual loss. However, once visual loss and other organ failure develop, patient motivation for glycemic control may increase and patients may then improve their control. One limitation of our study is the chart review design. We determined the visual acuity for only 65.6% of the patients. Although this figure may appear low, no health plan has reported higher frequencies of eye examination and the compliance with annual eye examinations was 64% in WESDR.10 In addition, another study reported the frequency of eye examinations among persons with diabetes to be less than 50%.11 Considering our frequency of noncompliance, our reported prevalence probably overestimates the true prevalence of visual impairment, because

underestimate of the actual utilization. Among eyes with vitreous hemorrhage, between 45%–50% had documentation of vitrectomy. The Diabetic Retinopathy Vitrectomy Study (DRVS) reported the benefits of vitrectomy. Although early vitrectomy was beneficial, the treatment effect was observed in the group of younger patients with Type I diabetes.7,8 The low rate of vitrectomy can be explained by the higher prevalence of older patients with Type 2 diabetes in this study. One unexpected finding was the similarity in glycosylated hemoglobin between patients with and without visual loss (Tables 4 and 5). Previous studies had shown that glycolated hemoglobin is a good predictor for progression of retinopathy.9 One explanation for why this association was not observed in current study may be the 240

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TABLE 6. Use of Laser and Vitrectomy Among Those With Visual Acuity ⬍20/40 in the Better Eye and the Worse Eye

% (n) of eyes with proliferative diabetic retinopathy (PDR) Of those with PDR, % (n) with documentation of pan retinal photocoagulation % (n) with clinical significant macular edema (CSME) Of those with CSME, % with documentation of focal photocoagulation within one month of diagnosis % (n) with vitreous hemorrhage Of those with vitreous hemorrhage, % (n) with vitrectomy surgery Of those with vitrectomy surgery, % (n) done within 6 months Of those with vitrectomy, % done within 1 year

Better Eye (N ⫽ 56)

Worse Eye (N ⫽ 163)

26.8% (15)

19.6% (32)

73.3% (11)

75.0% (24)

26.8% (15)

21.5% (35)

40.0% (6)

40.0% (14)

Cause

% (n)

Proliferative diabetic retinopathy and vitreous hemorrhage Proliferative diabetic retinopathy and macular edema Macular edema Macular degeneration Optic nerve problem Vascular occlusions Amblyopia Cataracts and cataract surgery related Corneal problems Other Total

24.2 (16) 7.7 (5) 10.8 (7) 18.5 (12) 7.7 (5) 6.2 (4) 6.2 (4) 6.2 (4) 4.6 (3) 7.7 (5) 100 (65)

REFERENCES

21.4% (12)

12.3% (20)

50.0 (6)

45.0% (9)

33.3% (2)

33.3% (3)

83.3% (5)

88.9% (8)

patients who do not comply with eye examinations are more likely to be asymptomatic. Another problem is that the visual acuity recorded may not be the best-corrected visual acuity. This, again, would likely overestimate the frequency of visual loss. The current report is the largest study of diabetic retinopathy outcomes among patients enrolled in a prepaid health plan. The information reported is not definitive and represents a preliminary investigation of the quality of eye care provided by one managed care plan. Further investigation is necessary to assess the process and outcomes of care.

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TABLE 7. Causes of Visual Acuity 20/200 or Worse

1. Goldzweig CL, Mittman BS, Carter GM, et al. Variations in cataract extraction rates in Medicare pre-paid and fee for service settings. JAMA 1997;277:1765–1768. 2. Lee PP, Meredith LS, Whitcup SM, Spritzer K, Hays RD. A comparison of self-reported utilization of ophthalmic care for diabetes in managed care versus fee-for-service. Retina 1998; 18:356 –359. 3. Klein R, Klein BE, Moss SE. Visual impairment in diabetes. Ophthalmology 1984;91:1–9. 4. Harris MI, Klein R, Cowie CC, Rowland M, Byrd-Holt DD. Is the risk of diabetic retinopathy greater in non-Hispanic blacks and Mexican Americans than in non-Hispanic whites with type 2 diabetes? A U.S. population study. Diabetes Care 1998;21(8):1230 –1235. 5. Haffner SM, Fong D, Stern MP, et al. Diabetic retinopathy in Mexican Americans and non-Hispanic whites. Diabetes 1988;37:878 – 884. 6. Khadem JJ, Buzney SM, Alich KS. Practice patterns in diabetic retinopathy. Part 1: Analysis of retinopathy followup. Arch Ophthalmol 1999;117:815– 820. 7. The DRVS Research Group. Early vitrectomy for severe vitreous hemorrhage in diabetic retinopathy. DRVS Report 2. Arch Ophthalmol 1985;103:1644. 8. DRVS Research Group. Early vitrectomy for severe vitreous hemorrhage in diabetic retinopathy. Four year results of a randomized trial. DRVS Report 5. Arch Ophthalmol 1990; 108:958. 9. Diabetes Control and Complications Trial Research Group. Progression of retinopathy with intensive versus conventional treatment in the Diabetes Control and Complications Trial. Ophthalmol 1995;102(4):647– 661. 10. Moss SE, Klein R, Klein BE. Factors associated with having eye examinations in persons with diabetes. Arch Fam Med 1995;4:529 –534. 11. Brechner RJ, Cowie CC, Howie, et al. Ophthalmic examination among adults with diagnosed diabetes mellitus. JAMA 1993;270:1714 –1718.

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