Incidence of retinopathy and associated risk factors from time of diagnosis of insulin-dependent diabetes

Diabetic Retinopathy Clinical Practice Guidelines: Customized for Iranian Population

Purpose:

To customize clinical practice guidelines (CPGs) for management of diabetic retinopathy (DR) in the Iranian population.

Methods:

Three DR CPGs (The Royal College of Ophthalmologists 2013, American Academy of Ophthalmology [Preferred Practice Pattern 2012], and Australian Diabetes Society 2008) were selected from the literature using the AGREE tool. Clinical questions were designed and summarized into four tables by the customization team. The components of the clinical questions along with pertinent recommendations extracted from the above-mentioned CPGs; details of the supporting articles and their levels of evidence; clinical recommendations considering clinical benefits, cost and side effects; and revised recommendations based on customization capability (applicability, acceptability, external validity) were recorded in 4 tables, respectively. Customized recommendations were sent to the faculty members of all universities across the country to score the recommendations from 1 to 9.

Results:

Agreed recommendations were accepted as the final recommendations while the non-agreed ones were approved after revision. Eventually, 29 customized recommendations under three major categories consisting of screening, diagnosis and treatment of DR were developed along with their sources and levels of evidence.

Conclusion:

This customized CPGs for management of DR can be used to standardize the referral pathway, diagnosis and treatment of patients with diabetic retinopathy.

Chronic intraocular pressure elevation impairs autoregulatory capacity in streptozotocin-induced diabetic rat retina

PURPOSE

To assess ocular blood flow responses to acute IOP stress following 4 weeks of chronic IOP elevation in streptozotocin (STZ)-induced diabetic and control rats. We hypothesise that chronic IOP elevation for 4 weeks will further impair blood flow regulation in STZ-induced diabetic rats eyes.

METHODS

Two weeks following citrate buffer or STZ-injections chronic IOP elevation was induced in Long Evans rats via fortnightly intracameral injections of microspheres (15 μm) suspended in 5% polyethylene glycol. IOP was monitored daily. Electroretinography (ERG, -6.79-2.07 log cd s m(-2) ) was undertaken at Week 4 to compare photoreceptor (RmPIII ), ON-bipolar cell (Vmax ) and ganglion cell dominant ERG [scotopic threshold response (STR)] components. 4 weeks post-chronic IOP induction, ocular blood flow (laser Doppler flowmetry) was measured in response to acute IOP challenge (10-100 mmHg, in 5 mmHg steps, each 3 min).

RESULTS

Four weeks of chronic IOP (mean ± S.E.M., citrate: 24.0 ± 0.3 to 30.7 ± 1.3 and STZ-diabetes: 24.2 ± 0.2 to 31.1 ± 1.2 mmHg) was associated with reduced photoreceptor amplitude in both groups (-25.3 ± 2.2% and -17.2 ± 3.0%, respectively). STZ-diabetic eyes showed reduced photoreceptor sensitivity (citrate: 0.5 ± 1.8%, STZ-diabetic: -8.1 ± 2.4%). Paradoxically ON-bipolar cell sensitivity was increased, particularly in citrate control eyes (citrate: 166.8 ± 25.9%, STZ-diabetic: 64.8 ± 18.7%). The ganglion cell dominant STR was not significantly reduced in STZ-diabetic rats. Using acute IOP elevation to probe autoregulation, we show that STZ-diabetes impaired autoregulation compared with citrate control animals. The combination of STZ-diabetes and chronic IOP elevation further impaired autoregulation.

CONCLUSIONS

STZ-diabetes and chronic IOP elevation appear to be additive risk factors for impairment of ocular blood flow autoregulation.

Assessing progress in retinopathy outcomes in type 1 diabetes: comparing findings from the Wisconsin Diabetes Registry Study and the Wisconsin Epidemiologic Study of Diabetic Retinopathy

OBJECTIVE

The Wisconsin Diabetes Registry Study (WDRS) cohort consisted of patients diagnosed with type 1 diabetes in the same geographic region as, but 8-34 years later than the Wisconsin Epidemiologic Study of Diabetic Retinopathy (WESDR) cohort, providing a unique opportunity to assess changes in complications. We estimated the current prevalence and severity of diabetic retinopathy at 20 years of diabetes duration, compared these between eras, and evaluated the influence of diabetes management.

RESEARCH DESIGN AND METHODS

Twenty-year examinations, including fundus photographs, were completed on 305 WDRS subjects during 2007-2011. A subgroup of the WESDR cohort participated in one of four study visits during 1980-1996, at similar diabetes duration (n = 583). Adjusted ordinal logistic regression with three retinopathy severity categories was used to estimate odds ratios (ORs) of more severe retinopathy with diagnosis during an earlier era.

RESULTS

Mean hemoglobin A(1c) (HbA(1c)) was lower in WDRS than in WESDR (8.0% vs. 9.3% [P < 0.001], and 93.4% vs. 21.3% [P < 0.001]) used ≥3 daily insulin injections or an insulin pump. In WDRS, 18% had vision-threatening levels of retinopathy vs. 43% in WESDR. The adjusted OR of more severe retinopathy in the earlier era (OR 3.0 [95% CI 2.2-4.0]) was reduced by including 20-year HbA(1c) in the model (OR 2.2 [1.6-3.0]).

CONCLUSIONS

Retinopathy severity at a diabetes duration of 20 years is lower in the more recent era of type 1 diabetes. Updated projections should be used when informing newly diagnosed individuals of prognosis and for health care cost assessments. Current glycemic control explained a limited amount of the difference.

Prevalence and risk factors for diabetic microvascular complications in newly diagnosed type II diabetes mellitus. Sankara Nethralaya Diabetic Retinopathy Epidemiology and Molecular Genetic Study (SN-DREAMS, report 27)

PURPOSE

The aims of this study were to report the prevalence of various microvascular complications and to identify the various clinical and biochemical characteristics related to these complications in subjects with newly diagnosed type II diabetes.

METHODS

Of the 5999 subjects enumerated, 1414 subjects with diabetes (both known and newly diagnosed) were analyzed for the study. Among the diabetic subjects, 248 (17.5%) were newly diagnosed with diabetes and the remaining had history of diabetes. All subjects underwent a detailed standard evaluation to detect diabetic retinopathy (fundus photography), neuropathy (vibration pressure threshold), and nephropathy (microalbuminuria).

RESULTS

The prevalence of any form of microvascular complication was 30.2% (95% confidence interval [CI]=24.5-35.9). The prevalence of diabetic retinopathy was 4.8%, and that of diabetic nephropathy and neuropathy was 10.5%. The risk factors for developing any form of microvascular complication were increasing age (odds ratio [OR]=1.07, 95% CI=1.04-1.11, P<.0001), increasing systolic blood pressure (OR=1.03, 95% CI=1.01-1.06, P=.001), and increasing hemoglobin (OR=1.39, 95% CI=1.09-1.79, P=.011). The risk factors for diabetic retinopathy and diabetic nephropathy were increasing systolic blood pressure (OR=1.06 [P=.001] for retinopathy and OR=1.04 [P=.012] for nephropathy) and increasing hemoglobin (OR=2.20 [P=.007] for retinopathy and OR=1.57 [P=.023] for nephropathy). The risk factor for diabetic neuropathy was increasing age (OR=1.12, P<.0001).

CONCLUSIONS

Nearly one third of the newly diagnosed type II diabetes subjects had some form of microvascular complication; nephropathy, and neuropathy being commoner than retinopathy.

Revisiting Diabetes 2000: challenges in establishing nationwide diabetic retinopathy prevention programs

PURPOSE

To evaluate the impact of the Diabetes 2000 program, an initiative launched by the American Academy of Ophthalmology in 1990 to improve nationwide screening of diabetic retinopathy (DR) and to reduce the prevalence and severity of the condition.

DESIGN

Retrospective, observational case study of Diabetes 2000 program.

METHODS

This is a perspective piece with a review of literature and personal opinions.

RESULTS

Patients with diabetes are likely to see an increase in the disease burdens associated with DR unless effective programs for early detection and control of DR are implemented.

CONCLUSIONS

Despite recent efforts to educate both patients and physicians alike about the importance of routine DR screening, the lessons learned from the Diabetes 2000 program illustrate the need for new strategies capable of improving accessibility to high-quality eye care, increasing involvement of primary care physicians in DR screening and encouraging at-risk individuals to seek testing.

Diabetic retinopathy - An update

Management of diabetes should involve both systemic and ocular aspects. Control of hyperglycemia, hypertension and dyslipidemia are of major role in the management of diabetic retinopathy. In the ocular part; laser treatment remains the cornerstone of treatment of diabetic macular edema (focal/grid), severe non-proliferative and proliferative diabetic retinopathy (panretinal photocoagulation). There is a strong support to combination therapy. Using one or two intravitreal injections such as anti-VEGF and or steroid to reduce central macular thickness followed by focal or grid laser to give a sustained response may offer an alternative to treatment in diabetic macular edema. Anti-VEGF were found to be effective as an adjunct therapy in proliferative diabetic retinopathy patient who is going to have vitrectomy for vitreous hemorrhage with neovascularization, panretinal photocoagulation, and other ocular surgery such as cases with neovascular glaucoma and cataract with refractory macular edema.

The Wisconsin Epidemiologic Study of Diabetic Retinopathy: XXII the twenty-five-year progression of retinopathy in persons with type 1 diabetes

OBJECTIVE

To examine the 25-year cumulative progression and regression of diabetic retinopathy (DR) and its relation to various risk factors.

DESIGN

Population-based study.

PARTICIPANTS

A total of 955 insulin-taking persons living in an 11-county area in southern Wisconsin with type 1 diabetes diagnosed before age 30 years who participated in a baseline examination (1980-1982) and at least 1 of 4 follow-up (4-, 10-, 14-, and 25-year) examinations or died before the first follow-up examination (n = 64).

METHODS

Stereoscopic color fundus photographs were graded using the modified Airlie House classification and the Early Treatment Diabetic Retinopathy Study retinopathy severity scheme.

MAIN OUTCOME MEASURES

Progression and regression of DR status.

RESULTS

The 25-year cumulative rate of progression of DR was 83%, progression to proliferative DR (PDR) was 42%, and improvement of DR was 18%. Progression of DR was more likely with less severe DR, male sex, higher glycosylated hemoglobin, an increase in glycosylated hemoglobin level, and an increase in diastolic blood pressure level from the baseline to the 4-year follow-up. Increased risk of incidence of PDR was associated with higher glycosylated hemoglobin, higher systolic blood pressure, proteinuria greater body mass index at baseline, and an increase in the glycosylated hemoglobin between the baseline and 4-year follow-up examinations. Lower glycosylated hemoglobin and male sex, as well as decreases in glycosylated hemoglobin and diastolic blood pressure during the first 4 years of follow-up, were associated with improvement in DR. Persons diagnosed most recently with a similar duration of diabetes had a lower prevalence of PDR independently of glycosylated hemoglobin level, blood pressure level, and presence of proteinuria.

CONCLUSIONS

These data show relatively high 25-year cumulative rates of progression of DR and incidence of PDR. The lower risk of prevalent PDR in more recently diagnosed persons possibly reflects improvement in care over the period of the study.

Risk Factors for Diabetic Retinopathy among Jordanian Diabetics

PURPOSE

To identify the risk factors associated with diabetic retinopathy among diabetic patients at Jordan University Hospital.

METHODS

A total of 986 patients with diabetes mellitus were assessed at Jordan University Hospital. The assessment included detailed relevant history, complete medical and ophthalmic evaluation.

RESULTS

Out of the 1961 eye examined, 64.1 percent had one form of diabetic retinopathy; 54.8 percent had nonproliferative diabetic retinopathy (NPDR), 9.3 percent had proliferative diabetic retinopathy (PDR) and 30.8 percent had maculopathy. Of all participants, 23.5 percent had combined NPDR and maculopathy while 7.6 percent had PDR and maculopathy. Using logistic regression analysis it was shown that old age group, long duration of diabetes, poor glycemic control, uncontrolled blood pressure and the presence of nephropathy were significantly associated with diabetic retinopathy. The incidence of maculopathy was significantly associated with the presence of hypertension, protienuria and high cholesterol level.

CONCLUSION

The challenge for the primary care physician and diabetologist is to attain excellent glycemic control, aggressive control of blood pressure and normalization of blood lipid in order to reduce the risk of blindness and lessen the burden from diabetic retinopathy.

Diabetic Retinopathy in Type II Diabetics Detected by Targeted Screening Versus Newly Diagnosed in General Practice

Introduction: The aim of this study was to compare the occurrence of diabetic retinopathy in targeted screening diabetic patients (Group I) with newly diagnosed diabetic patients in general practice (Group II). Materials and Methods: This was an observational cross-sectional study. Data were obtained from 25,313 subjects who participated in the diabetic screening camps, and 128 newly diagnosed diabetes who presented to the diabetic retinopathy screening camps in general practice in rural and urban south India. The study variables were collected from all patients who underwent eye examination from the target screening detected diabetics [(n = 173) Group I] and those newly diagnosed in general practice [(n = 128) Group II]. The variations in prevalence of diabetic retinopathy and sight-threatening diabetic retinopathy in Group I and Group II and the factors affecting it were identified. Results: The occurrence of diabetic retinopathy was 6.35% (95% CI, 2.5-9.5) in Group I and 11.71% (95% CI, 5.6-16.4) in Group II. No significant difference was observed on occurrence of diabetic retinopathy, including sight-threatening retinopathy, in rural versus urban population and in Group I versus Group II. Patients diagnosed in general practice (Group II) with systolic blood pressure (BP) >140 were more likely to have retinopathy (P = 0.02). Conclusions: Diabetic retinopathy including sight-threatening complications was found at the time of diagnosis of diabetes in the targeted screening group as well as in newly diagnosed diabetics in the general practice group. Key words: Diabetes mellitus, Diabetic retinopathy, General practice, Screening

Lower-than-expected prevalence and severity of retinopathy in an incident cohort followed during the first 4-14 years of type 1 diabetes: the Wisconsin Diabetes Registry Study

The authors examined the development of diabetic retinopathy in a population-based cohort of persons with incident type 1 diabetes to investigate the possibility of lowered retinopathy prevalence and severity compared with previous US studies. A total of 474 diabetic persons from Wisconsin were followed from diagnosis through 4-14 years' duration during 1990-2002. Retinopathy was determined by fundus photography at 4, 7, 9, and 14 years' duration. Risk of developing retinopathy was modeled on demographic and diabetes-care characteristics by means of a generalized linear model using the complementary log-log link for interval-censored data. Prevalence of retinopathy increased with duration of diabetes, from 6% at 4 years to 73% at 14 years, and was highest among adults (> or =20 years of age). Risk of developing retinopathy increased with increasing duration, worse glycemic control, and age up to 20 years. Indicators of diabetes care were related to retinopathy through their effect on glycemic control. Improvements in diabetes care leading to better glycemic control may have contributed to the much lower prevalence and less severe retinopathy observed than expected on the basis of a previous report from the same region of Wisconsin. The observed decreased prevalence has important implications for persons with type 1 diabetes, since retinopathy is a serious microvascular complication.

Epidemiology of diabetic retinopathy and macular oedema: a systematic review

AIMS

To systematically review the literature on the prevalence and incidence of diabetic retinopathy (DR) and macular oedema (MO).

METHODS

A search of the bibliographic databases (Medline, Embase, CINAHL) was conducted up to October 2001. Selected relevant studies were scrutinized and included in the review.

RESULTS

A total of 359 studies were included. The studies were reported in nearly 100 different journals and in over 50 countries. The majority of the studies were US-based, with large studies such as the Wisconsin Epidemiologic Study of Diabetic Retinopathy dominating the literature. The studies were quite dated and highly heterogeneous in nature in terms of patient selection with variable inclusion criteria (age range, gender, diabetes duration and type, ethnicity, comorbidity, and DR status, assessment, and classification).

CONCLUSIONS

There are inconsistencies between epidemiological studies, and differences in study methods may contribute to conflicting reports of prevalence and incidence of DR and MO in diabetic populations. As new therapies for DR and its associated complications emerge, the need to capture and monitor new epidemiological data becomes increasingly important to be able to assess the impact and effectiveness of these therapies. Robust, longitudinal capture of patient data is, therefore, essential to evaluate the impact of current practice on the epidemiology of diabetic eye complications.

Integrating the principles of evidence-based practice: testing and diagnosis

The intention of the clinical practice guideline (CPG) column has included increasing readers' familiarity with the range of available evidence-based recommendations, while stimulating dialogue regarding application of those recommendations in practice. This column introduces the first article in a series of three written to describe a framework in which the principles of evidence-based practice can be applied. This article uses a clinical scenario to illustrate considerations relevant to the selection and application of a CPG in practice.

Prevalence of retinopathy differs with age at onset of diabetes in a population of patients with Type 1 diabetes

AIM

The VISS study (Vascular complications in South-east Sweden) investigates prevalence and incidence of vascular complications in a population with Type 1 diabetes, from a well-defined geographical area and followed from diagnosis with HbA1c measurement.

METHOD

The study population comprised all 440 patients with Type 1 diabetes onset before the age of 36 years, onset during 1983-1987, and at the time of onset living within the counties of Jönköping, Kalmar or Ostergötland. Retinopathy was examined with fundus photography 1994-1995, and classified according to a modified Airlie House protocol.

RESULTS

Fundus photographs from 390 patients were evaluated. In 277 (71%) patients no retinopathy was seen. The prevalence of retinopathy increased from 11% among patients < 5 years old at diabetes onset, to 48% among those 15-19 years old at diabetes onset, and then decreased to 30% for patients 30-35 years old at diabetes onset (P for chi2 for linear trend for all ages 0.017, for age at onset 0-19 years P = 0.0003), without corresponding differences in duration or HbA1c between patients with different onset age. Patients with HbA1c in the highest quartile (> 8.3% HbA1c) had a relative risk of 2.4 (95% confidence interval (CI) 1.7-3.2) of having any retinopathy compared with patients with lower HbA1c, and a relative risk of 7.1 (95% CI 3.0-16.7) of having other forms of retinopathy than microaneurysms.

CONCLUSION

In patients with diabetes duration of 6-13 years, the prevalence of retinopathy is clearly related to glycaemic control. Furthermore, the risk of retinopathy varies with different age at onset, independently of differences in duration or glycaemic control.

[Socio-demographic and clinical characteristics of a patient population with diabetes mellitus]

OBJECTIVES

To describe sociodemographic and clinical characteristics of a diabetic population. To relate sociodemographic and clinical evolutionaries variables.

DESIGN

Descriptive transversal study.

SETTING

Three urban Primary Health Centers (PHC). Participants. Diabetic patients attended in these PHC.Measurements.

VARIABLES

sociodemographic and clinical through an individualized survey and a medical record review.

RESULTS

1495 patients were studied from whom 96% were diabetic type 2. Age: 66 years old (SD 12). Sex: 56% were women. Education level: 62 didn't have finished their primary studies. Family: 71% live together with a partner. Years of evolution: Diabetes (DM) < 10 years: 47% in type 1; 64% in type 2.

RISK FACTORS

DM 1: smokers 40%; hypertension (HTA) 7%; DM 2: smokers 12%; HTA 51%; obesity 26%; hypercholesterolemia 28%; hypertriglyceridemia 17%. Chronic complications: DM 1: retinopathy (DR) 26%; nephropathy (Nf) 3.5%; ischemic heart disease (IHD) 3.5%; periferic arteriopathy (PA) 7%; Cerebrovascular accident (CVA) 2%; peripheric neuropathy (PN) 5%. DM 2: DR 14%; Nf 13%; IHD 12%; PA 9%; CVA 5%; PN 4%; autonomic neuropathy 3%. Metabolic control DM 2: 67% HbA1c 7.5. Best metabolic control in DM with less years of evolution (p = 0.001). Treatment DM 2: 32% diet, 51% oral treatment, 13% insulin, 4% mixed. No relation with cultural level and family situation with metabolic control. In chronic complications only DR were more prevalent in patients with less cultural level (p = 0.037).

CONCLUSIONS

Less cultural level doesn't influence neither metabolic control nor appearance chronic complications, except DR. The knowledge of diabetic population attended has allowed to detect the need of reinforce the intervention for decrease smoking and increase chronic complications detection.

[Possible genetic causes for late complications of diabetes mellitus]

BACKGROUND

Hyperglycemia occurs in every patient with diabetes mellitus. It is the most important factor in the development of diabetic complications. However, the onset, intensity and the progression of complications show large interindividual variations. Manifestation in families and the lack of complications in some diabetics with poor metabolic control indicate a genetic predisposition to develop diabetic complications like nephropathy, neuropathy and angiopathy.

NEPHROPATHY

Diabetic nephropathy occurs only in 25 to 40% of the diabetic patients. Therefore a genetic risk factor for this complication is very likely. Various variations in genes like ACE-gene and angiotensinogen-gene have been described, which could be associated with the development of diabetic nephropathy.

NEUROPATHY

Peripheral diabetic neuropathy occurs in up to 66% of all diabetics. Therefore and because of the possible pathological mechanisms genetic risk factors like variations in the Na/K-ATPase-gene and in the aldose reductase-gene are discussed.

RETINOPATHY

An association between diabetic retinopathy and polymorphisms in the ACE-gene and the aldose reductase-gene seems very unlikely, because up to 75% of the diabetic patients suffer from retinopathy after 15 years of diabetes.

MACROANGIOPATHY

A large number of studies show an association between diabetic macroangiopathy and genetic variations in the ACE-gene (I/D-variant) and the paraoxonase-gene (2 isoforms).

CONCLUSION

Based on the current evidence for associations of genetic markers with diabetic complications, the generation of an individual risk profile based on genetic markers seems to be possible. In addition to near euglycemia genetic markers could direct therapeutic strategies and lead to new therapeutic approaches.

Risk factors for diabetic retinopathy among Saudi diabetics

PURPOSE

To describe the incidence of, and risk factors associated with, diabetic retinopathy in diabetic persons assessed at a Saudi diabetes centre.

METHODS

Five hundred and two patients with diabetes mellitus assessed by our service were studied. There were 174 patients (34.7%) with insulin-dependent diabetes mellitus (IDDM) and 328 patients (65.3%) with non-insulin-dependent diabetes mellitus (NIDDM).

RESULTS

The incidence of retinopathy was 157/502 (31.3%). The incidence was 42.5% in patients with IDDM and 25.3% in those with NIDDM. By logistic regression analysis, it was shown that old age (>60 years), insulin use, long duration of diabetes (>10 years), poor diabetes control, and the presence of nephropathy were significantly associated with the incidence of retinopathy. On the basis of the magnitudes of the regression coefficients in the hazard function, long duration of diabetes was the most important independent risk factor for the development of retinopathy; the presence of nephropathy, age >60 years, poor diabetes control, and use of insulin were less important (regression coefficients: 1.9, 1.71, 1.331, 0.8508 and 0.6178, respectively). The incidence of macular oedema was significantly associated with the presence of hypertension and high cholesterol levels in patients with IDDM. Polycotomous regression analysis showed that the presence of nephropathy was the only factor significantly associated with the severity of retinopathy.

CONCLUSIONS

The significant associations with poor control and duration of diabetes provide further strong evidence for the benefits of optimal glycaemic control. Other potentially modifiable risk factors for retinopathy may be important, including elevated blood pressure and serum cholesterol.

The temporal development of retinopathy and nephropathy in type 1 diabetes mellitus during 15 years diabetes duration

In this prospective study, the 10- and 15-year incidence and course of retinopathy were examined in relation to medical risk indicators from 3.1 +/- 1.9 (mean -/+ SD) years diabetes duration and onwards in 29 adult type 1 diabetic patients treated under routine care. A total of 28 patients were followed for 10 years and 20 patients for 15 years diabetes duration. After 10 years diabetes duration, 11 patients had developed any retinopathy (ten patients background retinopathy and one patient clinically-significant macular oedema). After 15 years diabetes duration, 16 patients had developed any retinopathy (12 patients developed background retinopathy and four patients developed potentially sight-threatening retinopathy, i.e. clinically significant macular oedema (n = 2) or severe non-proliferative retinopathy (n = 2)). None of the patients developed proliferative retinopathy. No differences were seen in mean HbA1c values between patients without any retinopathy and patients with background retinopathy, whereas patients who developed potentially sight-threatening retinopathy had higher mean HbA1c levels than patients without any retinopathy. Patients who developed potentially sight-threatening retinopathy had higher levels of mean HbA1c both after 10 (9.7 +/- 1.6 vs 6.9 +/- 1.5%; P < 0.05) and 15 years diabetes duration (9.3 +/- 1.2 vs 7.1 +/- 1.3%; P < 0.05), compared to patients without any retinopathy. They also had higher levels of mean HbA1c than patients with background retinopathy after 15 years diabetes duration (9.3 +/- 1.2 vs 7.7 +/- 1.1%; P < 0.05). There were no differences in blood pressure levels between patients who developed retinopathy and those who did not. Only two patients developed clinical signs of nephropathy (urinary albumin 320-1590 mg/l) after 12 and 13 years diabetes duration, respectively. At those time points, both patients had already developed background retinopathy since 2 years. In conclusion, the present study shows that the incidence of retinopathy is associated with the duration of diabetes and that there is a strong association between the degree of metabolic control and development of potentially sight-threatening retinopathy. The study also indicates that the development of retinopathy does not seem to be associated with hypertension or clinical signs of nephropathy.

Ocular neovascularization: an epidemiologic review

Neovascularization occurs in many eye diseases, and its epidemiologic impact is significant. However, data on the prevalence and incidence of ocular neovascularization have never been compiled to demonstrate its pervasiveness. This overview of ocular angiogenesis provides a review of the epidemiologic literature for neovascularization in various parts of the eye, including the cornea, iris, retina, and choroid. Relevant disease states are reviewed, as are their risk factors, so that their pathogenesis can be better understood. Data on the prevalence and incidence of the major diseases involving angiogenesis are synthesized to provide statistical evidence of the span and magnitude of ocular neovascularization. These prevalence and incidence data on ocular neovascularization are extrapolated to USA population data where possible, and "worst-case" estimates are calculated as well. Information was gathered with a search of the MEDLINE database, published monographs and volumes, and consultation with a number of primary authors. This study attempts to unify much of past and present epidemiologic research, and the information is presented in sections divided according to the anatomy of the eye.

The Wisconsin Epidemiologic Study of Diabetic Retinopathy: XVII. The 14-year incidence and progression of diabetic retinopathy and associated risk factors in type 1 diabetes

OBJECTIVE

To examine the 14-year incidence and progression of diabetic retinopathy and macular edema and its relation to various risk factors.

DESIGN

Population-based incidence study.

SETTING

The study was conducted in an 11-county area in southern Wisconsin.

PARTICIPANTS

Six hundred thirty-four insulin-taking persons with diabetes diagnosed before age 30 years participated in baseline, 4-year, 10-year, and 14-year follow-up examinations.

MAIN OUTCOME MEASURES

The 14-year progression of retinopathy, progression to proliferative retinopathy, and incidence of macular edema were detected by masked grading of stereoscopic color fundus photographs using the modified Airlie House classification and the Early Treatment Diabetic Retinopathy Study retinopathy severity scheme.

RESULTS

The 14-year rate of progression of retinopathy was 86%, regression of retinopathy was 17%, progression to proliferative retinopathy was 37%, and incidence of macular edema was 26%. Progression of retinopathy was more likely with less severe retinopathy, being male, having higher glycosylated hemoglobin or diastolic blood pressure at baseline, an increase in the glycosylated hemoglobin level, and an increase in diastolic blood pressure level from the baseline to the 4-year follow-up. Increased risk of proliferative retinopathy or incidence of macular edema was associated with more severe baseline retinopathy, higher glycosylated hemoglobin at baseline, and an increase in the glycosylated hemoglobin between the baseline and 4-year follow-up examination. The increased risk of proliferative retinopathy was associated with the presence of hypertension at baseline, whereas the increased risk of a participant having macular edema develop was associated with the presence of gross proteinuria at baseline. Lower glycosylated hemoglobin at baseline was associated with improvement in retinopathy.

CONCLUSIONS

These data suggest relatively high 14-year rates of progression of retinopathy and incidence of macular edema. These data also suggest that a reduction of hyperglycemia and hypertension may result in a beneficial decrease in the progression to proliferative retinopathy.