Prevalence of retinopathy and proteinuria in type 1 diabetics in Iceland

Screening for diabetic retinopathy: new perspectives and challenges

Although the prevalence of all stages of diabetic retinopathy has been declining since 1980 in populations with improved diabetes control, the crude prevalence of visual impairment and blindness caused by diabetic retinopathy worldwide increased between 1990 and 2015, largely because of the increasing prevalence of type 2 diabetes, particularly in low-income and middle-income countries. Screening for diabetic retinopathy is essential to detect referable cases that need timely full ophthalmic examination and treatment to avoid permanent visual loss. In the past few years, personalised screening intervals that take into account several risk factors have been proposed, with good cost-effectiveness ratios. However, resources for nationwide screening programmes are scarce in many countries. New technologies, such as scanning confocal ophthalmology with ultrawide field imaging and handheld mobile devices, teleophthalmology for remote grading, and artificial intelligence for automated detection and classification of diabetic retinopathy, are changing screening strategies and improving cost-effectiveness. Additionally, emerging evidence suggests that retinal imaging could be useful for identifying individuals at risk of cardiovascular disease or cognitive impairment, which could expand the role of diabetic retinopathy screening beyond the prevention of sight-threatening disease.

Longitudinal Screening for Diabetic Retinopathy in a Nationwide Screening Program: Comparing Deep Learning and Human Graders

OBJECTIVE

To evaluate diabetic retinopathy (DR) screening via deep learning (DL) and trained human graders (HG) in a longitudinal cohort, as case spectrum shifts based on treatment referral and new-onset DR.

METHODS

We randomly selected patients with diabetes screened twice, two years apart within a nationwide screening program. The reference standard was established via adjudication by retina specialists. Each patient's color fundus photographs were graded, and a patient was considered as having sight-threatening DR (STDR) if the worse eye had severe nonproliferative DR, proliferative DR, or diabetic macular edema. We compared DR screening via two modalities: DL and HG. For each modality, we simulated treatment referral by excluding patients with detected STDR from the second screening using that modality.

RESULTS

There were 5,738 patients (12.3% STDR) in the first screening. DL and HG captured different numbers of STDR cases, and after simulated referral and excluding ungradable cases, 4,148 and 4,263 patients remained in the second screening, respectively. The STDR prevalence at the second screening was 5.1% and 6.8% for DL- and HG-based screening, respectively. Along with the prevalence decrease, the sensitivity for both modalities decreased from the first to the second screening (DL: from 95% to 90%, p = 0.008; HG: from 74% to 57%, p < 0.001). At both the first and second screenings, the rate of false negatives for the DL was a fifth that of HG (0.5-0.6% vs. 2.9-3.2%).

CONCLUSION

On 2-year longitudinal follow-up of a DR screening cohort, STDR prevalence decreased for both DL- and HG-based screening. Follow-up screenings in longitudinal DR screening can be more difficult and induce lower sensitivity for both DL and HG, though the false negative rate was substantially lower for DL. Our data may be useful for health-economics analyses of longitudinal screening settings.

Prevalence of Blindness and Visual Impairment among Jordanian Diabetics

PURPOSE

To investigate the prevalence of blindness and visual impairment among a population of Jordanian diabetics.

METHODS

A total of 986 diabetic patients were fully assessed, including complete history, examination, and laboratory tests. All patients underwent detailed eye examination, which included visual acuity, slit-lamp examination, tonometry, funduscopy, and fundus fluorescein angiography (FFA).

RESULTS

Of all patients examined, 53.2% were male and 46.8% were female. The mean age and duration of diabetes were 55.3 and 11.9 years. Of all patients, 93.3% had type 2 while 6.7% had type 1 diabetes mellitus (DM). Over half (50.3%) were on oral hypoglycemic agents, 34% on insulin, and 14.5% on both types of treatment, whereas only 1.2% were on diet alone. The mean value for HbA1c was 7.7%. The prevalence of blindness among participants was found to be 7.4%, while 10.1% were visually impaired. Diabetic retinopathy (DR) was present in 64.1%, 37.8% had cataract, and 8.7% had undergone cataract surgery. Using multivariate logistic regression analysis, visual impairment was significantly associated with age, treatment of diabetes, and DR, while only age and retinopathy were significantly related to blindness.

CONCLUSIONS

DM is a common disease in Jordan and DR is highly prevalent among Jordanian diabetics. National screening and educational programs are highly needed to reduce the risk of blindness and visual impairment among diabetic patients.

Clinical Components of Telemedicine Programs for Diabetic Retinopathy

Diabetic retinopathy is a leading cause of new-onset vision loss worldwide. Treatments supported by large clinical trials are effective in preserving vision, but many persons do not receive timely diagnosis and treatment of diabetic retinopathy, which is typically asymptomatic when most treatable. Telemedicine evaluation to identify diabetic retinopathy has the potential to improve access to care, but there are no universal standards regarding camera choice or protocol for ocular telemedicine. We review the literature regarding the impact of imaging device, number and size of retinal images, pupil dilation, type of image grader, and diagnostic accuracy on telemedicine assessment for diabetic retinopathy. Telemedicine assessment of diabetic retinopathy has the potential to preserve vision, but further development of telemedicine specific technology and standardization of operations are needed to better realize its potential.

The Diabetic Retinopathy Screening Workflow: Potential for Smartphone Imaging

Complications of diabetes mellitus, namely diabetic retinopathy and diabetic maculopathy, are the leading cause of blindness in working aged people. Sufferers can avoid blindness if identified early via retinal imaging. Systematic screening of the diabetic population has been shown to greatly reduce the prevalence and incidence of blindness within the population. Many national screening programs have digital fundus photography as their basis. In the past 5 years several techniques and adapters have been developed that allow digital fundus photography to be performed using smartphones. We review recent progress in smartphone-based fundus imaging and discuss its potential for integration into national systematic diabetic retinopathy screening programs. Some systems have produced promising initial results with respect to their agreement with reference standards. However further multisite trialling of such systems' use within implementable screening workflows is required if an evidence base strong enough to affect policy change is to be established. If this were to occur national diabetic retinopathy screening would, for the first time, become possible in low- and middle-income settings where cost and availability of trained eye care personnel are currently key barriers to implementation. As diabetes prevalence and incidence is increasing sharply in these settings, the impact on global blindness could be profound.

Prevalence of diabetic retinopathy in various ethnic groups: a worldwide perspective

The alarming rise in diabetes prevalence is a global public health and economic problem. Diabetic retinopathy is the most common complication of diabetes and the leading cause of blindness among working-age populations in the Western world. Screening and prompt treatment of diabetic retinopathy are not top priorities in many regions of the world, because the impacts of other causes of preventable blindness remain an issue. Ethnicity is a complex, independent risk factor for diabetic retinopathy. Observations from white populations cannot be extrapolated fully to other ethnic groups. The prevalence of diabetic retinopathy, sight-threatening diabetic retinopathy, and clinically significant macular edema are higher in people of South Asian, African, Latin American, and indigenous tribal descent compared to the white population. Although all ethnic groups are susceptible to the established risk factors of diabetic retinopathy-such as length of exposure and severity of hyperglycemia, hypertension, and hyperlipidemia-ethnic-specific risk factors also may influence these rates. Such risk factors may include differential susceptibility to conventional risk factors, insulin resistance, differences in anthropometric measurements, truncal obesity, urbanization, variations in access to healthcare systems, genetic susceptibility, and epigenetics. The rates of nonproliferative diabetic retinopathy appear to be declining in the United States, supporting the observation that better medical management of diabetes and prompt treatment of sight-threatening diabetic retinopathy substantially improve the long-term diabetic retinopathy incidence; studies from other parts of the world are limited and do not mirror this finding, however. We examine the ethnicity and region-based prevalence of diabetic retinopathy around the world and highlight the need to reinforce ethnicity-based screening and treatment thresholds in diabetic retinopathy.

Prevalence of ocular disease and blindness in a rural area in the eastern region of Iceland during 1980 through 1984

The main emphasis in this study is on the three most common potentially blinding diseases in the age group 43 years and older, i.e. cataract, age related macular degeneration and open angle glaucoma. The prevalence of all three diseases increases with advancing age (P less than 0.001, corr. greater than 0.8). In the age group 63 years and older there is a statistically significant difference in the occurrence of cataracts between females and males (P less than 0.02). Females outnumber males and the former appear to develop cataract at an earlier age than men. Among persons 73 years of age and older there is a statistically significant difference in the occurrence of open angle glaucoma between males and females (P less than 0.05), whereby males outnumbered females. Persons with age related macular degeneration were divided into an exudative group and an atrophic group. There was no sex difference in the atrophic group, whereas females outnumber males by 2:1 in the exudative group, which is mainly accounted for by overrepresentation of females 83 years and older. Persons 83 years and older who had age related macular degeneration also had cataracts in all instances and open angle glaucoma in 23.8% of cases. Sixteen persons were legally blind i.e. had visual acuity less than or equal to 6/60 in the better eye or visual field less than 10 degrees in the better eye. Eight persons thereof, were greater than or equal to 83 years of age.

Prognostic factors and retinopathy in type 1 diabetics in Iceland

Prognostic factors, particularly those related to metabolic control, were analysed individually over a period of 12 months prior to fundus photography in 149 type 1 (insulin-dependent, ketosis-prone) diabetics in Iceland. Patients without retinopathy in their first 20 years of diabetes visited the Diabetic Clinic significantly more frequently than those with retinopathy (p less than 0.05). Mean blood sugar values and mean per cent body weight did not differ between patients with or without retinopathy. Few between patients with or without retinopathy. Few patients were obese. In patients with 5-9 years' duration of diabetes, retinopathy was first seen after 7.7 +/- 0.3 years (mean +/- SEM). Those with retinopathy were significantly older at the time of the diagnosis of diabetes than those without eye lesions (p less than 0.025), a tendency also noted in those with 10-19 years' duration (p less than 0.10). Conversely, patients without retinopathy after diabetes for 20 years or more were significantly older at the time of diagnosis (p less than 0.02). They used significantly less insulin daily than those with retinal lesions (p less than 0.005) and 70% were females. Subsequently, a significant (p less than 0.047) male excess was found to characterize a group of patients with proliferative retinopathy.

Prevalence and causes of visual impairment and blindness in Icelanders aged 50 years and older: the Reykjavik Eye Study

PURPOSE

This study aimed to study the prevalences and causes of visual impairment and blindness in an Icelandic adult population.

METHODS

The Reykjavik Eye Study includes a random sample of citizens of Reykjavik aged > or = 50 years, with an equal proportion (6.4%) for each year of birth and each sex. A total of 1045 persons were examined, representing a response rate of 75.8%. All participants underwent an extensive ophthalmological examination using a standard protocol. We used World Health Organization (WHO) definitions for bilateral visual impairment (best corrected visual acuity [VA] < 6/18 or visual field of > or = 5 degrees and < 10 degrees around the fixation point in the better eye) and blindness (VA < 3/60 or visual field < 5 degrees in the better eye). We also used US criteria, which define bilateral visual impairment as present if VA is < 6/12 and blindness as present if VA is < or = 6/60 (both in the better eye). The causes of visual loss were determined for all participants found to be visually impaired in one or both eyes.

RESULTS

The prevalences of bilateral visual impairment and blindness were 0.96% (95% confidence interval [CI] 0.37-1.55) and 0.57% (95% CI 0.12-1.03), respectively, using the WHO criteria, and 2.01% (95% CI 1.16-2.86) and 0.77% (95% CI 0.24-1.29), respectively, using the US criteria. The prevalence rates were 4.40% and 5.45% for unilateral visual impairment and 1.72% and 3.06% for unilateral blindness, using the WHO and US criteria, respectively. Age-related macular degeneration (AMD) was the major cause of bilateral visual loss, whereas the most common causes of unilateral visual loss were, in this order, amblyopia, cataract and glaucoma.

CONCLUSIONS

Prevalence of visual loss increases with age. The leading cause of bilateral visual impairment and blindness was AMD, accounting for more than half of all cases, and cases of geographic atrophy outnumbered those of exudative AMD by two to one.

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.

Biennial eye screening in patients with diabetes without retinopathy: 10-year experience

AIMS

To evaluate the safety of every-other-year eye screening for patients with diabetes without retinopathy.

METHODS

Since 1994, patients with diabetes without retinopathy in Iceland have received eye screening every other year. 296 patients with diabetes who had no diabetic retinopathy in 1994/95 were followed with biennial eye examinations until they had developed retinopathy. The 10-year experience of this approach is reviewed.

RESULTS

Out of the 296 diabetic individuals, 172 did not develop diabetic retinopathy during the 10-year observation period. 96 patients developed mild non-proliferative retinopathy, six developed clinically significant diabetic macular oedema, 23 developed preproliferative retinopathy, and four developed proliferative diabetic retinopathy during the 10-year observation period. All the patients who developed macular oedema or proliferative retinopathy had already been diagnosed as having mild nonproliferative retinopathy and entered an annual screening protocol before the sight-threatening retinopathy developed. No patient had any undue delay in treatment.

CONCLUSION

Every other year screening for diabetic eye disease seems to be safe and effective in diabetics without retinopathy. Such an approach will reduce the number of screening visits more than 25%. This reduces health costs and strain on resources considerably and relieves the patients with diabetes from unnecessary clinic visits and examinations.

Screening compliance and visual outcome in diabetes

PURPOSE

To study the relationship between screening compliance and visual outcome in a screening programme for diabetic eye disease.

METHODS

A retrospective case control study. The screening compliance of all the diabetes patients (n = 22) listed at the Icelandic National Registry for the Blind (visual acuity <0.3) was compared to a matched group of 44 non-blind diabetes patients (visual acuity > or =0.3) who participated in the same screening programme for diabetic retinopathy. Glycaemic control (HbA1c), office blood pressure and cholesterol levels were assessed.

RESULTS

The study group had a significantly lower level of compliance with the screening programme (27% +/- 38% [mean +/- SD] versus 77% +/- 26% [mean +/- SD]; p < 0.0001). Macular oedema or proliferative diabetic retinopathy was found in 60% (13/22) of the study group when entering the screening programme, compared to 7% (3/44) in the control group. Blood pressure (except diastolic BP among type 1 diabetes mellitus), blood glucose and cholesterol levels were identical. The prevalence of blindness and low vision amongst diabetes patients in Iceland is about 0.5%.

CONCLUSIONS

There was a significant relationship between screening compliance and visual outcome in diabetes patients in our screening programme.

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.

Diabetic retinopathy, visual acuity, and medical risk indicators: a continuous 10-year follow-up study in Type 1 diabetic patients under routine care

The objective of this study was to describe incidence and progression of diabetic retinopathy in relation to medical risk indicators as well as visual acuity outcome after a continuous follow-up period of 10 years in a Type 1 diabetic population treated under routine care. The incidence and progression of retinopathy and their association to HbA(1c), blood pressure, urinary albumin, serum creatinine levels, and insulin dosage were studied prospectively in 452 Type 1 diabetic patients. The degree of retinopathy was classified as no retinopathy, background, or sight-threatening retinopathy, i.e. clinically significant macular edema, severe nonproliferative, or proliferative retinopathy. Impaired visual acuity was defined as a visual acuity <0.5 and blindness as a visual acuity < or =0.1 in the best eye. In patients still alive at follow-up (n=344), 61% (69/114) developed any retinopathy, 45% (51/114) background retinopathy, and 16% (18/114) sight-threatening retinopathy. Progression from background to sight-threatening retinopathy occurred in 56% (73/131). In 2% (6/335), visual acuity dropped to <0.5 and in less than 1% (3/340) to < or =0.1. Patients who developed any retinopathy and patients who progressed to sight-threatening retinopathy had higher mean HbA(1c) levels over time compared to those who remained stable (P<.001 in both cases). Patients who developed any retinopathy had higher levels of mean diastolic blood pressure (P=.036), whereas no differences were seen in systolic blood pressure levels between the groups. Cox regression analysis, including all patients, showed mean HbA(1c) to be an independent risk indicator for both development and progression of retinopathy, whereas mean diastolic blood pressure was only a risk indicator for the incidence of retinopathy. Metabolic control is an important risk indicator for both development and progression of retinopathy, whereas diastolic blood pressure is important for the development of retinopathy in Type 1 diabetes. The number of patients who became blind during 10 years of follow-up was low.

The relationship of prorenin values to microvascular complications in patients with insulin-dependent diabetes mellitus

We have performed a cross-sectional analysis of the relationship between prorenin values and the microvascular complications of diabetes in a well controlled population of insulin-dependent diabetes mellitus (IDDM) subjects. One hundred and thirty-nine subjects (75 men, 64 women, age 44 +/- 17 years; duration of diabetes 19 +/- 15 years), formed the study group. Sixty-seven subjects (48.2%) had no complications, 55 (39.6%) had retinopathy alone, and 17 (12.2%) had retinopathy and albuminuria. Patients with no complications had lower prorenin values than those with microvascular complications (p < 0.001), whilst patients with both albuminuria and retinopathy had higher values than those with retinopathy alone (p < 0.05). Retinopathy was associated with duration of diabetes (p < 0.0001), diastolic blood pressure (p < 0.02) and albuminuria (p < 0.0001) while albuminuria was associated with prorenin (p < 0.02), serum triglyceride (p < 0.01) and retinopathy (p < 0.001). Patients with albuminuria were 5.5 times more likely to have raised prorenin values (>80 ng/mL/h) than those with normal albumin excretion [95% confidence interval (CI): 1.48-20.12] and those with retinopathy alone were 2.5 times as likely (95% CI: 1.19-5.15). Eighty patients with IDDM (40 males, 40 females; age: 47 +/- 17 years; duration of diabetes: 20 +/- 15 years), had retinal photography performed to determine the association between the severity of retinopathy and prorenin values. Retinopathy was more severe in patients with retinopathy and albuminuria than in those with retinopathy alone (p < 0.002). When the prorenin values of patients with more marked retinopathy (eye grade greater than 3) were compared, prorenin values of those with retinopathy and albuminuria were greater than those of patients with retinopathy alone [269 (139-1406) versus 91 (41-273) ng/mL/h: geometric mean (range); p < 0.05]. Furthermore, when patients without albuminuria were considered, there was no significant difference between the prorenin levels of patients with more severe retinopathy (eye grade >3) when compared to patients with lesser degrees of retinopathy [91 (41-273) versus 69 (23-375). In patients with microvascular complications, prorenin values were independently predicted by albuminuria (p < 0.0001) and diastolic blood pressure (p < 0.02) but not the severity of retinopathy. In conclusion, prorenin values are significantly associated with the presence of microvascular complications in patients with IDDM. The association with albuminuria may be stronger than the association with retinopathy.

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.

Photographic detection of retinopathy in insulin-treated diabetes. A population study in the city of Tartu, Estonia

PURPOSE

To perform a cross-sectional baseline investigation of diabetic retinopathy prevalence and metabolic control.

METHODS

Using a register of insulin-dependent diabetes mellitus in Tartu (pop. 104,791), 175 patients were invited to fundus photography; 149 (89%) participated, 99 of them diagnosed with diabetes before the age of thirty. Four Kodachrome 64 photographs per eye were taken with a Canon CR4 - 45NM camera through tropicamide-dilated pupils; slides were projected and systematically graded. Capillary blood samples (n = 132) for HbA1c determination were mailed on filter paper. Following cysteine buffer elution, Mono S ion exchange chromatography was performed (reference range 3.7 to 5.3%).

RESULTS

Any diabetic retinopathy was found in 114 patients (76.5%; 95% confidence interval, CI, 70 to 83%); mild to moderate non-proliferative retinopathy in 59 (40%; 95% CI 32 to 48%); severe non-proliferative retinopathy in 29 (19.5%; 95% CI 13 to 26%); proliferative retinopathy in 26 (17%; 95% CI 11 to 24%); 47 patients (32%) needed laser photocoagulation. Vitreous haemorrhage was observed in 9 (6%) of subjects. In patients diagnosed with diabetes before the age of 30 years, prevalence of any retinopathy was 82% (95% CI 73 to 89%) and of proliferative retinopathy 23% (95% CI 15 to 33%). Median HbA1c was 9.7% for women and 8.6% for men (95% CI for difference 0.7 to 2.1%).

CONCLUSION

Retinopathy prevalences (76-82%) are the highest reported from population-based studies. Glycaemia levels were very high and should be gradually lowered. Methods capable of validation can be successfully introduced for population-based assessment of hyperglycaemia and retinopathy prevalences.

Active prevention in diabetic eye disease. A 4-year follow-up

Ten years after the foundation of a national diabetic eye screening program in 1980, we have established a low prevalence of blindness and partial sight in type 1 and type 2 diabetics in Iceland. We ask whether the screening program is also associated with a low incidence of blindness in diabetics. We now report the results of a prospective study on the 4-year incidence of diabetic retinopathy and visual impairment in type 1 diabetics with age at onset less than 30 years. Out of 205 patients participating at baseline, 175 patients (85.4%) participated over the full 4-year period. Patients were examined annually and received laser treatment according to Diabetic- and Early Treatment Diabetic Retinopathy Study criteria. The 4-year incidence of any retinopathy was 38.1%, of proliferative retinopathy 6.6%, and of macular edema 3.4%. Out of 174 patients, 7.4% showed improvement in visual acuity of 2 Snellen lines while 2.5% experienced worsening of visual acuity of 2 Snellen lines during the 4-year period. No diabetic suffered more than 2 lines deterioration of vision and none became legally blind. The incidence of retinopathy in Icelandic type 1 diabetics participating in our annual eye screening program is low and the visual acuity stable. Our results suggest that visual impairment in diabetics can be prevented with active regular screening and standard laser therapy.

Systematic screening for diabetic eye disease in insulin dependent diabetes

Under a national program established in 1980, the eyes of approximately 90% of the insulin dependent diabetic patients in Iceland have undergone annual eye examination and fundus photography. Laser treatment was given for proliferative retinopathy or diabetic macular edema according to Diabetic Retinopathy Study and Early Treatment Diabetic Retinopathy Study criteria. We report on 205 insulin-taking patients whose age at diagnosis was less than 30 years of age. Retinopathy was present in 106 (52%) patients and proliferative retinopathy in 26 (13%). 196 patients (96%) had visual acuity equal or better than 6/12 in their better eye, 6 patients (3%) with 6/18-6/48 in their better eye, and 2 patients (1%) equal or worse than 6/60 in their better eye.

The prevalence of diabetic retinopathy in northwest Spain. An epidemiological study of diabetic retinopathy in Galicia. I

The prevalence of retinopathy was studied in a group of 1179 diabetic patients attending 11 diabetologic centres in Gallica (Northwest of Spain). The age of the patients was 61.7 +/- 13.8 years, 43.8% were males and 56.2% females. The patients had had diabetes from 8.4 +/- 7.5 years, 30.4% were being treated with insulin, and 69.6% with oral antihyperglycaemics. 16.1% were aged under 40 years at onset as against 83.9% aged over 40 years. The prevalence of retinopathy was 44.7, in the whole group. Stepwise multiple regression analysis identified treatment time since onset and age at onset as the factors affecting prevalence, which was 61.8% in the insulin-treated subgroup vs 37% among those treated with oral antihyperglycaemics (p < 0.0001). The prevalence of proliferative diabetic retinopathy was 5.8% in the whole group.

Prevalence and risk factors of diabetic retinopathy among noninsulin-dependent diabetic subjects

In a population-based study in Taiwan, 11,478 subjects aged 40 years or older were screened for diabetes in one urban and five rural areas. Among the 715 subjects proven to have diabetes, 527 subjects underwent ophthalmoscopy. Diabetic retinopathy was present in 184 of the 527 subjects (35.0%), including background diabetic retinopathy in 157 subjects (30.0%), preproliferative diabetic retinopathy in 15 subjects (2.8%), and proliferative diabetic retinopathy in 12 subjects (2.2%). Diabetic retinopathy was correlated with the duration of diabetes and age at onset of diabetes, type of diabetes treatment, higher serum creatinine levels, and lower serum cholesterol levels. Several other factors, including gender, age, residential area, family income, educational level, control and family history of diabetes, body mass index, physical activity, exercise, cigarette smoking, stroke, ischemic heart disease, leg vessel disease, hypertension, and proteinuria, had no significant association with retinopathy. By multiple logistic regression analysis, duration of diabetes was the most important risk factor related to retinopathy. Diabetic subjects treated with insulin had a higher risk of developing retinopathy than those treated with dietary control (relative risk, 1.57; .05 < P < .10). The univariate analysis disclosed that proliferative diabetic retinopathy was related to older age at examination, older age at onset of diabetes, type of diabetes treatment, and presence of leg vessel disease. Insulin-treated diabetic subjects also had a higher risk of proliferative diabetic retinopathy than patients in whom diabetes was controlled by diet, with a relative risk of 2.51 (.05 < P < .10) in the multiple logistic regression analysis.

A nationwide cross-sectional study of retinopathy and microalbuminuria in young Norwegian type 1 (insulin-dependent) diabetic patients

A nationwide cohort of Type 1 (insulin-dependent) diabetic patients was studied to determine the prevalence of retinopathy and microalbuminuria and to evaluate the association to various risk factors. Of 600 subjects with mean age of 19.8 years (range 8.0-30.3) and a mean duration of diabetes of 10.5 years (range 6.2-17.3), 371 (60%) volunteered for a clinical examination which included fundus photography, timed overnight urine samples for albumin excretion rate, measurement of arterial blood pressure and determination of HbA1c. Retinopathy was found in 122 of 371 patients (32.8%), in 3 of 41 (7.3%) patients aged less than 13 years. The youngest subject with retinopathy was 9.6 years old. Microalbuminuria was found in 44 of 351 patients (12.5%), in 1 of 41 (2.4%) patients aged less than 13 years. The youngest subject with microalbuminuria was 11.5 years old. Mean HbA1c was 8.6% (normal range 4.5-601%). Patients with retinopathy had significantly higher mean age (p = 0.0001), longer mean duration of diabetes (p = 0.0001), higher mean HbA1c (p = 0.009), and higher mean arterial blood pressure (p = 0.0001) compared to patients without retinopathy. In microalbuminuric patients HbA1c (p = 0.001) and mean arterial blood pressure (p = 0.01) were significantly higher compared to non-microalbuminuric patients, but there was no difference in age or diabetes duration. In a multiple logistic regression model, age, HbA1c, duration of diabetes and mean arterial blood pressure were found to be significantly associated with retinopathy, while HbA1c, mean arterial blood pressure and onset before 13.0 years of age were found to be associated with microalbuminuria.(ABSTRACT TRUNCATED AT 250 WORDS)

The Wisconsin epidemiological study of diabetic retinopathy: a review

The WESDR has provided precise estimates of the prevalence, and 4-year incidence and progression of diabetic retinopathy. It has provided evidence of a possible causal relationship between specific risk factors, such as hyperglycemia and the development and progression of retinopathy. Our data support current recommendations for ophthalmologic examinations for people with diabetes. In 1990 we will reexamine the cohort to determine the 10-year incidence and progression of diabetic retinopathy, macular edema, and visual impairment.

The prevalence of retinopathy and associated medical risk factors in type I (insulin-dependent) diabetes mellitus

The prevalence of diabetic retinopathy and the associated medical risk factors, such as age at onset and duration of diabetes, metabolic control, blood pressure, albumin clearance and serum creatinine, were studied in 501 patients with type I diabetes mellitus. The prevalence of retinopathy, characterized as simplex, maculopathy, preproliferative, and proliferative, was 60.5%. Patients with retinopathy were younger at the onset of diabetes, and had a longer duration of disease. In patients with more than 10 years of diabetes, proliferative retinopathy was more frequent if onset was before they were 15 years old, despite the fact that the duration of diabetes did not differ. Patients with severe retinopathy had worse metabolic control, and were more frequently treated for hypertension. In addition, the systolic blood pressure was elevated in all groups of patients with any type of retinopathy, whereas the diastolic blood pressure was elevated only in patients with more severe forms. Patients with severe retinopathy also had higher levels of albumin clearance.

'Microalbuminuria' in type I (insulin-dependent) diabetic patients with and without retinopathy

We investigated the frequency of microalbuminuria (albumin excretion rate, AER greater than 15 micrograms/min) ('overnight' urine collection and radioimmunological evaluation) and its relation to retinopathy (assessed by fluorangiography) in 113 type I (insulin-dependent) diabetic subjects (aged 31 +/- 13 years; diabetes duration 11 +/- 7 years), all Albustix-negative. Sixty eight patients (60.2%) were free of retinal lesions, 31 (27.4%) had background retinopathy and 14 (12.4%) had proliferative retinopathy. Microalbuminuria was found in 25 patients (22%). Fifteen patients (13%) showed both retinopathy and microalbuminuria. Fifteen % (10/68) of the patients with no retinopathy and sixteen % (5/31) of those with background retinal lesions had microalbuminuria, while 29% (4/14) of the patients with proliferative retinopathy were normoalbuminuric. Among the 29 patients with diabetes for less than five years, 1 had retinopathy and 4 had microalbuminuria. Out of 15 patients with both retinopathy and microalbuminuria, 13 (87%) had had diabetes for more than 10 years. Diabetic retinopathy is more frequent than microalbuminuria (40 vs 22%). Although the linkage between retinopathy and microalbuminuria is weak, after ten years of diabetes the two complications may frequently coincide.

Recent developments in the understanding and management of diabetic retinopathy

The natural history of diabetic retinopathy, one of the leading causes of visual impairment in the United States, is well described; its pathogenesis, however, is poorly understood. The Diabetic Retinopathy Study and the Early Treatment of Diabetic Retinopathy Study have demonstrated that timely intervention with photocoagulation prevents visual loss. However, recent studies demonstrate that many diabetic patients are not being referred to ophthalmologists for timely treatment. Suggested management and referral strategies are presented in this article.

Relationship of duration and onset of diabetes to prevalence of diabetic retinopathy

In a population study of all registered insulin-treated diabetic patients on the Swedish island of Gotland, the prevalence of diabetic retinopathy was determined with ophthalmoscopy, biomicroscopy, and color photography. Retinopathy was present in 173 of 368 patients (47%) and reached a prevalence of 100% after 30 years of diabetes. Proliferative retinopathy was found in 48 subjects (13%) and was more common in females (17%) than in males (9.4%) (P = .01). By simple logistic regression test, the prevalence of total and proliferative retinopathy was correlated with both duration and age at onset of diabetes (P less than .001). However, on multiple regression analysis only the relationship with duration was statistically significant (P less than .001); age at onset was not (P greater than .2). Age had an additional influence only on background retinopathy with hard exudates, which were more frequent in older subjects (P less than .01). Thus, age at onset of diabetes was not correlated with the prevalence of total or proliferative retinopathy.

Aortic stiffness in insulin-dependent diabetics: an echocardiographic study

To assess the aortic stiffness (AS) in young (15-35 year old) insulin-dependent diabetics without manifestations of atherosclerotic disease or hypertension, M-mode echocardiography was used to measure relative changes in aortic diameter expressed as Aortic strain = Diameter change/Diastolic diameter-100% Aortic stiffness can be calculated from the formula AS = Pulse pressure/Aortic strain. Fifty-seven diabetics were investigated, 31 men (aged 23.6 +/- 5.6 years, mean +/- SD) and 26 women (aged 25.7 +/- 6.4 years). There were 26 healthy controls with similar blood pressure, 14 men (aged 25.0 +/- 5.5 years) and 12 women (aged 24.6 +/- 7.1). The AS in diabetic men was 14 +/- 8.0 (mean +/- SD) compared to 3.6 +/- 0.7 in controls (p less than 0.001). In diabetic women the AS was 5.8 +/- 3.1 compared to 4.3 +/- 1.3 in controls (p less than 0.05). Diabetic men also had much stiffer aortas than diabetic women (p less than 0.001). There was a linear correlation between AS and duration of diabetes in men (R = 0.70; (p less than 0.001). For females no such correlation was found, the AS frequently being within the range of the controls in spite of long duration of the disease. In males there was a significant correlation between AS and retinopathy (R = 0.49; p less than 0.01) and an inverse correlation with HDL-cholesterol/total cholesterol ratio (R = 0.51; p less than 0.01). In diabetic females AS was significantly greater in smokers (7.0 +/- 3.7) than in non-smokers (4.2 +/- 2.2; p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

The prevalence of retinopathy in insulin-dependent juvenile-onset diabetes mellitus--a fluorescein-angiographic study

A fluorescein-angiographic study was performed comprising all 171 insulin-dependent diabetics with debut at less than or equal to 40 years of age who were census registered on the island of Gotland 1981-82. Children under 15 years of age were excluded. The overall prevalence of diabetic retinopathy was 66%, being 11% at 0-5 years duration of diabetes, 42% at 6-10 years, 84% at 11-15 years, 90% at 16-30 years and 100% after 30-years duration. Proliferative retinopathy was first seen after 11 years duration, it had a prevalence of 18% and was twice as common in females as in males. Neovascularization was seen in 25% of patients with IDDM debut at less than or equal to 20 years of age and in only 7% of those with IDDM debut at 21-40 years (P less than 0.01). Pigment epithelial defects were found in 91 subjects (56%).

Diabetic retinopathy and insulin therapy in a rural diabetic population

The prevalence of diabetic retinopathy was lower in a rural diabetic population when compared to the prevalence of diabetic retinopathy in medical center clinic populations. Adult-onset (Type II) diabetics were at greater risk for developing diabetic retinopathy shortly after diagnosis than newly diagnosed cases of juvenile diabetes (Type I). The use of insulin positively correlated with the prevalence of diabetic retinopathy in this rural population.