Diabetic retinopathy: contemporary prevalence in a well-controlled population

Association of thyroid stimulating hormone and time in range with risk of diabetic retinopathy in euthyroid type 2 diabetes

AIMS

Diabetic retinopathy (DR) can occur even in well-controlled type 2 diabetes, suggesting residual risks of DR in this population. In particular, we investigated the combined effect of thyroid function and glycaemic control assessed by an emerging metric, time in range (TIR) with DR.

MATERIALS AND METHODS

In this cross-sectional study, a total of 2740 euthyroid patients with type 2 diabetes were included. Thyroid indicators, including thyroid-stimulating hormone (TSH), free triiodothyronine, free thyroxine, thyroid peroxidase antibody and thyroglobulin antibody, were measured. TIR was measured using continuous glucose monitoring data.

RESULTS

Overall, the multivariable-adjusted odds ratios (ORs) for DR across ascending tertiles of TSH were 1.00 (reference), 1.06 (95% confidence interval [CI] 0.85-1.32), and 1.48 (95% CI 1.19-1.85). Even in well-controlled participants who achieved a TIR target of >70% (n = 1449), the prevalence of DR was 23.8%, which was significantly related to TSH (OR = 1.54, 95% CI 1.12-2.12, highest vs. lowest TSH tertile). Participants were then classified into 6 groups by the joint categories of TIR (>70%, ≤70%) and TSH (tertiles), and the multivariable-adjusted ORs for DR were highest in TIR ≤70% and the highest TSH tertile group (OR = 1.96, 95% CI 1.41-2.71) when compared with the TIR >70% and the lowest TSH tertile group.

CONCLUSIONS

In type 2 diabetic patients with well-controlled glycaemic status, higher TSH within the normal range was associated with an increased risk of DR. The combination of suboptimal TSH and TIR further increased the risk of DR.

Statins and renal disease progression, ophthalmic manifestations, and neurological manifestations in veterans with diabetes: A retrospective cohort study

Background

Statins increase insulin resistance, which may increase risk of diabetic microvascular complications. Little is known about the impact of statins on renal, ophthalmologic, and neurologic complications of diabetes in practice. The objective of this study was to examine the association of statins with renal disease progression, ophthalmic manifestations, and neurological manifestations in diabetes.

Methods

This is a retrospective cohort study, new-user active comparator design, that included a national Veterans Health Administration (VA) patients with diabetes from 2003 to 2015. Patients were age 30 years or older and were regular users of the VA with data encompassing clinical encounters, demographics, vital signs, laboratory tests, and medications. Patients were divided into statin users or nonusers (active comparators). Statin users initiated statins and nonusers initiated H2-blockers or proton pump-inhibitors (H2-PPI) as an active comparator. Study outcomes were: 1) Composite renal disease progression outcome; 2) Incident diabetes with ophthalmic manifestations; and 3) Incident diabetes with neurological manifestations.

Results

Out of 705,774 eligible patients, we propensity score matched 81,146 pairs of statin users and active comparators. Over a mean (standard deviation) of follow up duration of 4.8 (3) years, renal disease progression occurred in 9.5% of statin users vs 8.3% of nonusers (odds ratio [OR]: 1.16; 95% confidence interval [95%CI]: 1.12–1.20), incident ophthalmic manifestations in 2.7% of statin users vs 2.0% of nonusers (OR: 1.35, 95%CI:1.27–1.44), and incident neurological manifestations in 6.7% of statin users vs 5.7% of nonusers (OR: 1.19, 95%CI:1.15–1.25). Secondary, sensitivity, and post-hoc analyses were consistent and demonstrated highest risks among the healthier subgroup and those with intensive lowering of LDL-cholesterol.

Conclusions

Statin use in patients with diabetes was associated with modestly higher risk of renal disease progression, incident ophthalmic, and neurological manifestations. More research is needed to assess the overall harm/benefit balance for statins in the lower risk populations with diabetes and those who receive intensive statin therapy.

Predictive factors associated with anatomical and functional outcomes following panretinal photocoagulation in people with proliferative diabetic retinopathy

PURPOSE

To determine effects of baseline characteristics and laser type performed on outcomes in people with proliferative diabetic retinopathy (PDR) undergoing panretinal photocoagulation (PRP).

METHODS

Medical records of all consecutive patients with PDR naïve to PRP, identified using an electronic database, evaluated at the Macula Clinic, Belfast Health and Social Care Trust, receiving their first PRP between 1st January 2016 and 30th June 2017, and followed for a minimum of 6 months following stabilization of PDR, were retrospectively reviewed. Outcomes included time to stabilization following PRP, progression of PDR, and mean change in best-corrected visual acuity from baseline to last follow-up. Cox regression was used to estimate hazard ratios (HRs) for the effect of baseline characteristics and type of laser on outcomes following treatment.

RESULTS

One hundred and fourteen patients (135 eyes) with a mean age of 57.6 (SD: 13.1) years were included, 67% males. People receiving pattern or mixed laser had a statistically significantly delayed stabilization (HR: 0.54, p=0.004; and HR: 0.41, p=0.001, respectively) and increased risk of progression (HR: 1.83, p=0.028; and HR: 2.04, p=0.018, respectively) when compared to those receiving standard laser. Among other potential predictors in multivariable regression analysis, only vitreous hemorrhage and fibrosis or traction at baseline increased risk of progression (HR: 1.70, p=0.017; and HR: 4.14, p<0.001 respectively). Baseline characteristics and type of laser had no statistically significant effect on vision.

CONCLUSION

These findings should be considered when selecting laser treatment, planning surveillance, and counselling patients with PDR undergoing PRP.

Derivation and Validation of Essential Predictors and Risk Index for Early Detection of Diabetic Retinopathy Using Electronic Health Records

Diabetic retinopathy (DR) is a leading cause for blindness among working-aged adults. The growing prevalence of diabetes urges for cost-effective tools to improve the compliance of eye examinations for early detection of DR. The objective of this research is to identify essential predictors and develop predictive technologies for DR using electronic health records. We conducted a retrospective analysis on a derivation cohort with 3749 DR and 94,127 non-DR diabetic patients. In the analysis, an ensemble predictor selection method was employed to find essential predictors among 26 variables in demographics, duration of diabetes, complications and laboratory results. A predictive model and a risk index were built based on the selected, essential predictors, and then validated using another independent validation cohort with 869 DR and 6448 non-DR diabetic patients. Out of the 26 variables, 10 were identified to be essential for predicting DR. The predictive model achieved a 0.85 AUC on the derivation cohort and a 0.77 AUC on the validation cohort. For the risk index, the AUCs were 0.81 and 0.73 on the derivation and validation cohorts, respectively. The predictive technologies can provide an early warning sign that motivates patients to comply with eye examinations for early screening and potential treatments.

Diabetic retinopathy in well-controlled type 2 diabetes: Role of glycaemic memory

AIMS

As diabetic retinopathy (DR) can occur even in well-controlled patients with type 2 diabetes (T2D), our study sought to determine whether it might be related to 'glucose memory' by evaluating patients' HbA1c over previous years and their skin autofluorescence (SAF).

METHODS

In 334 patients with T2D and HbA1c levels≤8%, their available values of HbA1c from previous years were collected, and their SAF measured by an advanced glycation end-product (AGE) reader. Binary logistic regression analysis was then used to correlate DR with previously recorded HbA1c levels and to SAF, with adjustment for DR risk factors [age, gender, BMI, duration of diabetes, arterial hypertension, diabetic kidney disease (DKD), blood lipid levels and statin treatment].

RESULTS

Our patients were mostly men (58.4%) aged 63±10years, with a duration of diabetes of 13±10years and HbA1c=7.1±0.7%. Of these patients, 84 (25.1%) had DR, which was associated with longer duration of diabetes and greater prevalence of DKD. A total of 605 HbA1c values from previous years were collected for time periods -4±3 months (n=255), -16±4months (n=152), -30±4months (n=93) and -62±26 months (n=105). After adjustment, the association between DR and having an HbA1c higher than the median was significant only for the oldest previous HbA1c values: OR=6.75, 95% CI: 1.90-23.90. Moreover, SAF values were higher in those with DR [2.95±0.67 arbitrary units (AU)] vs 2.65±0.65 AU with no DR (P<0.01) and were also associated with the oldest previous HbA1c values (P<0.01).

CONCLUSION

Our study found that 25.1% of our well-controlled T2D patients had DR, which was related to both their HbA1c levels from 5years prior to study admission and their SAF values, a marker of glucose memory.

Relationship between body fat and diabetic retinopathy in patients with type 2 diabetes: a nationwide survey in Korea

PURPOSE

To evaluate the association of body mass index (BMI), waist circumference, and body fat with diabetic retinopathy (DR) in Korean patients with type 2 diabetes.

METHODS

Among the 1130 participants 19 years of age or older with type 2 diabetes enrolled in the nationwide survey, a total of 887 participants were included in the analyses after excluding patients with ungradable fundus images. The presence and severity of DR were graded with seven-field fundus photographs. The associations between DR and anthropometric parameters and total body fat, which was assessed by dual-energy X-ray absorptiometry, were analysed using multivariate logistic regression models.

RESULTS

Patients were divided into three groups according to severity of DR: no DR (n = 702, 79.1%), mild/moderate DR (n = 130, 14.7%), and vision-threatening DR (n = 55, 6.2%). In multivariate-adjusted analyses, higher BMI (adjusted odds ratio [aOR], 0.80; 95% confidence interval [CI], 0.70-0.92; P = 0.001), larger waist circumference (aOR, 0.96; 95% CI, 0.91-1.00; P = 0.047), and higher total body fat (aOR, 0.86; 95% CI, 0.79-0.92; P < 0.001) were significantly associated with a lower risk of vision-threatening DR. In sex-stratified analyses, however, only total body fat in women showed a significant inverse association with the presence of DR (aOR, 0.93; 95% CI, 0.88-0.98; P < 0.001) and independently with the severity of DR (P for trend = 0.004).

CONCLUSION

In Korean patients with type 2 diabetes, obese patients might be less likely to have vision-threatening DR. Total body fat in women appears to be inversely and independently associated with DR prevalence and progression.

Incidence of diabetic eye disease among migrants: A cohort study of 100,000 adults with diabetes in Denmark

AIMS

To examine the incidence rates of any and referable diabetic retinopathy (DR) among migrants in Denmark.

METHODS

Nationwide clinical data on diabetes patients followed since 2005 were analysed. Patients were classified according to country of origin into six groups: Denmark, other Europe, Sub Saharan Africa, Middle East/North Africa, Asia, and America/Oceania. A total of 93,780 or 110,897 patients without any (including unspecific diagnoses) or referable (proliferative) DR at baseline were analyzed. We estimated event rates and hazard ratios (HRs) for incidence of any and referable DR according to country of origin.

RESULTS

After an average follow-up of 3.59 years 6727 had incident any DR and 4747 patients had referable DR. Compared to people of Danish origin, migrants from the Middle East/North Africa and Asia had a higher risk of any and referable DR after adjustment for age, sex, body mass index, smoking status, types and duration of diabetes, clinic type (general practice vs outpatient clinic), HbA1c, blood pressure and lipid levels. The associations remained significant after further adjustment for frequency of eye screening.

CONCLUSIONS

Migrants from the Middle East/North Africa and Asia were at increased risk of developing any and referable DR compared to native Danes, and these differences were not fully explained by differences in underlying clinical, diabetic and cardiometabolic risk factors.

Participation in a National Lifestyle Change Program is associated with improved diabetes Control outcomes

AIMS

Clinical trials show lifestyle change programs are beneficial, yet large-scale, successful translation of these programs is scarce. We investigated the association between participation in the largest U.S. lifestyle change program, MOVE!, and diabetes control outcomes.

METHODS

This longitudinal, retrospective cohort study used Veterans Health Administration databases of patients with diabetes who participated in MOVE! between 2005 and 2012, or met eligibility criteria (BMI ≥25kg/m²) but did not participate. Main outcomes were diabetic eye disease, renal disease, and medication intensification.

RESULTS

There were 400,170 eligible patients with diabetes, including 87,366 (22%) MOVE!

PARTICIPANTS

Included patients were 96% male, 77% white, with mean age 58years and BMI 34kg/m². Controlling for baseline measurements and age, race, sex, BMI, and antidiabetes medications, MOVE! participants had lower body weight (-0.6kg), random plasma glucose (-2.8mg/dL), and HbA1c (-0.1%) at 12months compared to nonparticipants (each p<0.001). In multivariable Cox models, MOVE! participants had lower incidence of eye disease (hazard ratio 0.80, 95% CI 0.75-0.84) and renal disease (HR 0.89, 95% CI 0.86-0.92) and reduced medication intensification (HR 0.82, 95% CI 0.80-0.84).

CONCLUSIONS

If able to overcome participation challenges, lifestyle change programs in U.S. health systems may improve health among the growing patient population with diabetes.

Angiogenesis and Inflammation Crosstalk in Diabetic Retinopathy

Diabetic retinopathy (DR) is one of the most prevalent microvascular complications of diabetes and one of the most frequent causes of blindness in active age. Etiopathogenesis behind this important complication is related to several biochemical, hemodynamic and endocrine mechanisms with a preponderant initial role assumed by polyol pathways, increment of growth factors, accumulation of advanced glycation end products (AGE), activation of protein kinase C (PKC), activation of the renin-angiotensin-aldosterone system (RAAS), and leukostasis. Chronic and sustained hyperglycemia works as a trigger to the early alterations that culminate in vascular dysfunction. Hypoxia also plays an essential role in disease progression with promotion of neovascularization and vascular dystrophies with vitreous hemorrhages induction. Thus, the accumulation of fluids and protein exudates in ocular cavities leads to an opacity augmentation of the cornea that associated to neurodegeneration results in vision loss, being this a devastating characteristic of the disease final stage. During disease progression, inflammatory molecules are produced and angiogenesis occur. Furthermore, VEGF is overexpressed by the maintained hyperglycemic environment and up-regulated by tissue hypoxia. Also pro-inflammatory mediators regulated by cytokines, such as tumor necrosis factor (TNF-α) and interleukin-1 beta (IL-1β), and growth factors leads to the progression of these processes, culminating in vasopermeability (diabetes macular edema) and/or pathological angiogenesis (proliferative diabetic retinopathy). It was found a mutual contribution between inflammation and angiogenesis along the process. J. Cell. Biochem. 117: 2443-2453, 2016. © 2016 Wiley Periodicals, Inc.

Association between body mass index and diabetic retinopathy in Chinese patients with type 2 diabetes

AIMS

To explore the factors mediating the relationship between body mass index (BMI) and diabetic retinopathy (DR) in Chinese type 2 diabetes patients.

METHODS

This is a cross-sectional study. Data of 2,533 patients with type 2 diabetes were studied from the Shanghai Diabetes Registry Database. DR was assessed using non-mydriatic fundus photography and graded as non-DR, mild-moderate (DR I-II), and sight-threatening (DR III-IV). BMI (kg/m(2)) was classified as normal weight (18.5 ≤ BMI < 25), overweight (25 ≤ BMI < 30), and obese (BMI ≥ 30). β cell function was evaluated by fasting C-peptide (FCP).

RESULTS

DR was present in 701 (27.7 %) patients. Patients with DR had lower BMI (24.3 vs. 24.9 kg/m(2), P = 0.001) and fasting C-peptide (1.46 vs. 1.86 ng/ml, P < 0.001) than those without DR. The association between BMI (2 kg/m(2) interval) and DR was U-shaped; patients with BMI 28-29.9 kg/m(2) had the lowest DR rate. Compared with normal weight, overweight was associated with reduced risk of any DR [odds ratio (OR) 0.73], DR I-II (OR 0.76), and DR III-IV (OR 0.64) after adjustment for sex, age at diabetes diagnosis, and duration of diabetes. This negative association attenuated after adjustment for other confounders and became nonsignificant after further adjustment for FCP. Patients with different BMI categories had similar DR risk when stratified by FCP tertiles.

CONCLUSION

Overweight patients have lower DR prevalence than normal weight individuals, which may be attributable to better β cell function in overweight patients.

The prognosis of diabetic retinopathy in patients with type 2 diabetes since 1996-1998: the Skaraborg Diabetes Register

Diabetes mellitus is the main reason for visual impairment among patients of working ages. The aim of this paper was to investigate the prognosis of eye complications in patients with diabetes during 10 years of follow-up and contributing risk factors. Data from ophthalmological records (occurrence of retinopathy and laser treatment and visual acuity), and clinical data (blood pressure, glycosylated hemoglobin (HbA1c), body mass index (BMI), and antihypertensive treatment) from the Skaraborg Diabetes Register were retrieved in the Skaraborg Screening Program of 1,258 patients diagnosed during 1996-1998. Kaplan Meyer survival analysis and Log Rank test were used to analyze eye complications in 773 patients with type 2 diabetes and ≤70 years at diagnosis. Visual acuity was above the limit for driving license in 96 % of 548 patients and only nineteen patients were treated by laser. At diagnosis of diabetes, mean HbA1c was 6.7 ± 1.7 % (59 ± 7.1 mmol/mol), and systolic blood pressure was 142.9 ± 0.7 mmHg; neither changed significantly during follow-up. Retinopathy appeared about 1 year, and maculopathy 2 years earlier, if HbA1c ≥ 7 % (63 mmol/mol) at diagnosis (p < 0.001 and p < 0.006). Antihypertensive treatment, higher BMI, and higher age at diagnosis were associated with less retinopathy during follow-up. Most patients with diabetes develop little retinopathy for the first 10 years after diagnosis. High HbA1c at baseline was associated with retinopathy and maculopathy during follow-up. Antihypertensive treatment, probably a proxy for regular controls and early detection of diabetes, was associated with less retinopathy.

Tromsø eye study: prevalence and risk factors of diabetic retinopathy

PURPOSE

To determine the prevalence of visual impairment, retinopathy and macular oedema, and assess risk factors for retinopathy in persons with diabetes.

METHODS

The present study included 514 participants with diabetes aged 46-87 years from the Tromsø Eye Study, a sub-study of the population-based Tromsø Study in Norway. Visual acuity was measured using an auto-refractor. Retinal images from both eyes were graded for retinopathy and macular oedema. We collected data on risk factor exposure from self-report questionnaires, clinical examinations, laboratory measurements and case note reviews. Regression models assessed the cross-sectional relationship between potential risk factors and diabetic retinopathy.

RESULTS

The prevalence of visual impairment (corrected Snellen visual acuity <20/60 in the better-seeing eye) was 1.6%. The prevalence of diabetic retinopathy was 26.8% and macular oedema 3.9%. In a multivariable logistic regression model, retinopathy was associated with longer diabetes duration (odds ratio, OR 1.07, 95% CI 1.03-1.11), insulin use (OR 2.14, 95% CI 1.19-3.85), nonfasting glucose (OR 1.07, 95% CI 1.00-1.15) and microalbuminuria (OR 1.89, 95% CI 1.28-2.81). Sub-group analyses showed association between retinopathy and even low levels of microalbuminuria (1.16 mg/mmol).

CONCLUSION

The findings suggest that low levels of microalbuminuria may be a useful risk predictor for identifying individuals with diabetes at high risk of retinopathy. The study confirms previous findings that insulin use, longer diabetes duration and higher levels of blood glucose are associated with retinopathy in persons with diabetes. The prevalence of diabetic retinopathy was similar as reported in other studies.

Four-year incidence of diabetic retinopathy in a Spanish cohort: the MADIABETES study

Objective

To evaluate the incidence of diabetic retinopathy in patients with Type 2 Diabetes Mellitus, to identify the risk factors associated with the incidence of retinopathy and to develop a risk table to predict four-year retinopathy risk stratification for clinical use, from a four-year cohort study.

Design

The MADIABETES Study is a prospective cohort study of 3,443 outpatients with Type 2 Diabetes Mellitus, sampled from 56 primary health care centers (131 general practitioners) in Madrid (Spain).

Results

The cumulative incidence of retinopathy at four-year follow-up was 8.07% (95% CI = 7.04–9.22) and the incidence density was 2.03 (95% CI = 1.75–2.33) cases per 1000 patient-months or 2.43 (95% CI = 2.10–2.80) cases per 100 patient-years. The highest adjusted hazard ratios of associated risk factors for incidence of diabetic retinopathy were LDL-C >190 mg/dl (HR = 7.91; 95% CI = 3.39–18.47), duration of diabetes longer than 22 years (HR = 2.00; 95% CI = 1.18–3.39), HbA1c>8% (HR = 1.90; 95% CI = 1.30–2.77), and aspirin use (HR = 1.65; 95% CI = 1.22–2.24). Microalbuminuria (HR = 1.17; 95% CI = 0.75–1.82) and being female (HR = 1.12; 95% CI = 0.84–1.49) showed a non-significant increase of diabetic retinopathy. The greatest risk is observed in females who had diabetes for more than 22 years, with microalbuminuria, HbA1c>8%, hypertension, LDL-Cholesterol >190 mg/dl and aspirin use.

Conclusions

After a four-year follow-up, the cumulative incidence of retinopathy was relatively low in comparison with other studies. Higher baseline HbA1c, aspirin use, higher LDL-Cholesterol levels, and longer duration of diabetes were the only statistically significant risk factors found for diabetic retinopathy incidence. This is the first study to demonstrate an association between aspirin use and diabetic retinopathy risk in a well-defined cohort of patients with Type 2 Diabetes Mellitus at low risk of cardiovascular events. However, further studies with patients at high cardiovascular and metabolic risk are needed to clarify this issue.

Hospitalized cardiovascular events in patients with diabetic macular edema

Background

Microvascular and macrovascular complications in diabetes stem from chronic hyperglycemia and are thought to have overlapping pathophysiology. The aim of this study was to investigate the incidence rate of hospitalized myocardial infarctions (MI) and cerebrovascular accidents (CVA) in patients with diabetic macular edema (DME) compared with diabetic patients without retinal diseases.

Methods

This was a retrospective cohort study of a commercially insured population in an administrative claims database. DME subjects (n = 3519) and diabetes controls without retinal disease (n = 10557) were matched by age and gender. Healthcare claims were analyzed for the study period from 1 January 2002 to 31 December 2005. Incidence and adjusted rate ratios of hospitalized MI and CVA events were then calculated.

Results

The adjusted rate ratio for MI was 2.50 (95% CI: 1.83-3.41, p < 0.001) for DME versus diabetes controls. Predictors of MI events were heart disease, history of acute MI, and prior use of antiplatelet or anticoagulant drugs. The adjusted rate ratio for CVA was 1.98 (95% CI: 1.39-2.83, p < 0.001) for DME versus diabetes controls. Predictors of CVA events were cardiac arrhythmia, Charlson comorbidity scores, history of CVA, hyperlipidemia, and other cerebrovascular diseases.

Conclusion

Event rates of MI or CVA were higher in patients with DME than in diabetes controls. This study is one of few with sufficient sample size to accurately estimate the relationship between DME and cardiovascular outcomes.

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.

Potential Therapeutic Roles for Inhibition of the PI3K/Akt/mTOR Pathway in the Pathophysiology of Diabetic Retinopathy

Novel therapeutics such as inhibitors of PI3K/Akt/mTOR pathway presents a unique opportunity for the management of diabetic retinopathy (DR). Second generation mTOR inhibitors have the prospect to be efficacious in managing various stages of disease progression in DR. During early stages, the mTOR inhibitors suppress HIF-1α, VEGF, leakage, and breakdown of the blood-retinal barrier. These mTOR inhibitors impart a pronounced inhibitory effect on inflammation, an early component with diverse ramifications influencing the progression of DR. These inhibitors suppress IKK and NF-κB along with downstream inflammatory cytokines, chemokines, and adhesion molecules. In proliferative DR, mTOR inhibitors suppress several growth factors that play pivotal roles in the induction of pathological angiogenesis. Lead mTOR inhibitors in clinical trials for ocular indications present an attractive treatment option for chronic use in DR with favorable safety profile and sustained ocular pharmacokinetics following single dose. Thereby, reducing dosing frequency and risk associated with chronic drug administration.

Five-year visual outcome following laser photocoagulation of diabetic macular oedema

OBJECTIVE

To evaluate the 5-year visual outcome associated with laser photocoagulation treatment of diabetic macular oedema (DMO), and to investigate the relationship between systemic factors and visual outcomes in a real-life setting.

METHODS

The mean annual visual outcomes and systemic parameters of 100 consecutive subjects with type 2 diabetes who underwent the first session of focal/grid macular laser photocoagulation for clinically significant macular oedema between 2003 and 2004 were collected retrospectively and compared with the outcomes of the laser arm of the Diabetic Retinopathy Clinical Research Network (DRCRN trial comparing intravitreal triamcinolone acetonide injection with laser photocoagulation treatment for DMO). The primary outcome measures included the mean change in visual acuity (VA) in 5 years and the influence of systemic factors on final visual outcome.

RESULTS

The mean change in VA at 5 years was -5.23 in a real-life setting for an inner city population. The 3-year outcome was inferior to the clinical trial results with more people gaining vision (≥15 letter gain) in the DRCRN group compared with this cohort (26 vs 9%). Furthermore, three times more patients lost vision (>15 letter loss) in the real-life setting of this cohort compared with the clinical trial results of the DRCRN group (27 vs 8%, respectively).

CONCLUSIONS

The visual outcomes and the control of systemic factors of patients with DMO in this cohort were inferior to those recruited for the clinical trial involving the DRCRN group.

Influence of glycosylated hemoglobin on sight-threatening diabetic retinopathy: a population-based study

AIM

To evaluate the role of glycosylated hemoglobin (HbA1c) on the occurrence of sight-threatening diabetic retinopathy (STDR) in urban Chennai, Tamil Nadu, India.

METHODS

A total of 5999 individuals were enumerated from the Chennai metropolis. Of these, 1414 subjects with diabetes were included for data analysis in the study. STDR or non-STDR groups were classified based on the fundus photographs. HbA1c was measured (Bio-Rad DiaSTAT™ HbA1c Reagent Kit) by the liquid chromatography technique.

RESULTS

A statistically significant difference (p < 0.05) was noted in the duration of diabetes, gender, body mass index, HbA1c, micro- and macro-albuminuria between both non-STDR and STDR groups as compared to the no-diabetic retinopathy (DR) group. On multivariate analysis, HbA1c (non-STDR: odd's ratio OR = 1.23; 95% confidence interval CI = 1.15-1.32; p < 0.0001; STDR: OR = 1.31 95% CI = 1.14-1.52; p < 0.0001) was found to be significantly associated with non-STDR and STDR when compared with the no-DR group. The Receiver Operating Characteristic analysis showed that the cut-off value of 8.0 had 75.6% sensitivity and 58.2% specificity with 64.9% maximum area under the curve.

CONCLUSION

HbA1c value >8.0% was significantly related with STDR. In a screening programme, the cut-off value of HbA1c >8.0% provided a maximum yield of STDR.

Prevention of diabetic eye disease: the commonest cause of blindness in individuals younger than 65 years

There has been a considerable advancement in the treatment of diabetes and understanding of the biochemical mechanisms underlying diabetic complications in the last 20 years. However, this advancement has not translated into a consistent reduction in diabetic retinopathy, one of the most frightening complications of diabetes mellitus. It is probable that greater attention to preventive intervention will help reduce the damage load in the next future, and that several drugs for the treatment of more advanced stages of diabetic retinopathy will become available. Competent strategies targeting prevention based on screening programs should be proposed to reduce the burden and to improve the clinical outcome of this devastating diabetes complication.

Prevalence and determinants of diabetic retinopathy in Al hasa region of saudi arabia: primary health care centre based cross-sectional survey, 2007-2009

PURPOSE

To evaluate the prevalence of diabetic retinopathy (DR) in the urban and rural areas of Al Hasa region of Saudi Arabia and to determine risk factors related to DR.

MATERIALS AND METHODS

This study was conducted on patient attending primary health care centers between July 2007 and June 2009. A retrospective chart review was conducted on subjects with diabetes mellitus greater than 18 years old. Ophthalmologists examined DR status through dilated pupils by using direct, indirect, and slit lamp bio-microscopy. Frequencies, percentage, and their 95% confidence intervals (CIs) were calculated. Odd's ratio was used to associate DR with possible risk factors. A P value less than 0.05 was considered statistically significant.

RESULTS

The prevalence of DR among 473 diabetic subjects was 30% (95% CI: 25.80-34.20). The odd ratios (ORs) of DR among diabetic residing in an urban area was significantly higher than diabetics residing in rural areas [OR = 1.94 (95% CI of OR 0.82-2.89)]. DR was associated to the duration of diabetes (adjusted OR = 1.70), uncontrolled blood sugar level (adjusted OR = 1.96), hyperlipidemia (adjusted OR = 2.04), and hypercholesterolemia (adjusted OR = 2.80).

CONCLUSIONS

DR appears to be a public health problem in the Al Hasa district of Saudi Arabia, and a planned approach is required to avoid severe visual impairment in patients with diabetes mellitus. Primary prevention and early detection could be implemented through primary health centers and non-ophthalmologists.

Changes in incidence of diabetes mellitus-related eye disease among US elderly persons, 1994-2005

OBJECTIVES

To determine if diabetic eye disease has changed over time among older Americans and to explore possibilities for observed change.

METHODS

We performed a longitudinal analysis of nationally representative Medicare data, the Medicare 5% sample, collected from January 1, 1991, through December 31, 2004, using standard claims data algorithms and cross-sectional analysis of the Medicare Current Beneficiary Survey.

RESULTS

Compared with Medicare beneficiaries first diagnosed with diabetes mellitus in 1994, those first diagnosed with diabetes in 1999 and in 2003 showed lower rates of background and proliferative diabetic retinopathy within 1 year after diagnosis and during 6 years of follow-up among the 1999 cohort. Six-year rates of surgical procedures for retinopathy were lower among beneficiaries in the 1999 cohort than in the 1994 cohort, and rates of glucose, lipid, and cholesterol monitoring were higher. In addition, hypertension was diagnosed more frequently among the 1999 cohort during 6 years. Data from the Medicare Current Beneficiary Survey showed higher rates of antihypertensive drug use among persons diagnosed with diabetes in 1999 compared with 1994.

CONCLUSIONS

Decreases in rates of diabetic retinopathy among persons newly diagnosed with diabetes enrolled in Medicare from 1994 to 2004 and concurrent improvements in primary care for diabetes suggest that better primary care has had an effect on the Medicare population, despite increasing rates of other adverse outcomes.

Scutellaria baicalensis enhances the anti-diabetic activity of metformin in streptozotocin-induced diabetic Wistar rats

Oxidative stress is the root cause of diabetic macro- and microvascular complications. Biochemical and epidemiological studies indicate that current treatments for diabetes do not reduce risks of developing complications, suggesting their inability to alleviate the levels of oxidative stress. This study in streptozotocin (STZ)-induced diabetic rats was carried out to investigate the effect of combining the antidiabetic drug, metformin, with an ethanolic extract of Scutellaria baicalensis, a plant whose root is known for its radical scavenging activity. Three groups of STZ-induced diabetic rats were given the following treatments for 30 days: (1) metformin 500 mg/kg, (2) S. baicalensis 400 mg/kg, (3) metformin 500 mg/kg + S. baicalensis extract 400 mg/kg. In addition, vehicle-treated diabetic and nondiabetic controls were used in the experiment. The rats treated with S. baicalensis and metformin + S. baicalensis had elevated hepatic activities of the antioxidant enzymes--superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) compared to the vehicle- and metformin-treated diabetic groups (p < 0.05). Plasma and hepatic lipid peroxide concentrations in the herb-treated and herb + metformin-treated groups were also significantly reduced (p < 0.05). In addition, the combined treatment caused significant elevations of plasma and pancreatic insulin levels and reductions of plasma and hepatic triglycerides (TG) and cholesterol levels. The study thus showed that S. baicalensis enhanced the antidiabetic effect of metformin in STZ-induced diabetic rats by improving the antioxidant status. It also increased pancreatic insulin content as well as improved the lipid profile in these rats.

Temporal trends in the age-specific prevalence of diabetes and diabetic retinopathy in older persons: Population-based survey findings

PURPOSE

To compare the age-specific prevalence of diabetes and diabetic retinopathy (DR) over 6 years.

METHODS

The Blue Mountains Eye Study (BMES) examined 3654 residents (82.4% response) aged >49 years in BMES I (1992-1994). Survivors (n = 2335) and newly eligible residents (n = 1174) were examined in BMES II (1997-2000). Diabetes was defined by history or fasting plasma glucose > or =7.0 mmol/L. DR was graded from 6-field retinal photographs using the Airlie House Classification. Age-specific prevalence in 5-year intervals was compared, as samples of each age group were independent.

RESULTS

The overall diabetes prevalence increased from 7.8 to 9.9% (p = 0.002) while the age-specific prevalence increased in age groups 60-74 years, over 6 years. A slightly higher prevalence of mild levels of DR (p = 0.018) but lower prevalence of moderate-severe levels of DR (p = 0.049) was evident in BMES II compared to BMES I. Factors significantly associated with DR prevalence were diabetes duration > or =20 years (BMES I, OR 7.6 [2.9-20.5]; BMES II, OR 6.1 [2.5-15.4]) and blood glucose level (BMES I, OR 1.1 [1.0-1.2]; BMES II, OR 1.2 [1.1-1.3] per mmol/L increase).

CONCLUSIONS

An increased prevalence of diabetes, but decreased prevalence of severe levels of DR, was documented in two survey samples from the same region over 6 years.

The 30-year natural history of type 1 diabetes complications: the Pittsburgh Epidemiology of Diabetes Complications Study experience

Declining incidences in Europe of overt nephropathy, proliferative retinopathy, and mortality in type 1 diabetes have recently been reported. However, comparable data for the U.S. and trend data for neuropathy and macrovascular complications are lacking. These issues are addressed using the prospective observational Pittsburgh Epidemiology of Childhood-Onset Diabetes Complications Study. Participants were stratified into five cohorts by diagnosis year: 1950-1959, 1960-1964, 1965-1969, 1970-1974, and 1975-1980. Mortality, renal failure, and coronary artery disease (CAD) status were determined on the complete cohort (n = 906) at 20, 25, and 30 years. Overt nephropathy, proliferative retinopathy, and neuropathy were assessed at 20 and 25 years on the subset of participants with a clinical examination. There was a decreasing trend by diagnosis year for mortality, renal failure, and neuropathy across all time intervals (P < 0.05), with the 1950-1959 cohort having a fivefold higher mortality at 25 years than the 1970s' cohorts. Proliferative retinopathy and overt nephropathy showed nonsignificant declines at 20 years (P < 0.16 and P < 0.13, respectively) and no change at 25 years. CAD event rates, which were lower than the other complications, also showed no trend. Although some type 1 diabetes complications (mortality, renal failure, and neuropathy) are declining, others (CAD, overt nephropathy, and proliferative retinopathy) show less favorable changes by 30 years.

Diabetic retinopathy in a multi-ethnic cohort in the United States

PURPOSE

To describe the prevalence and risk factors of diabetic retinopathy in a multi-ethnic US population of whites, blacks, hispanics, and chinese.

DESIGN

Cross-sectional study of 778 individuals from ages 45 to 85 years with diabetes, participating in the Multi-Ethnic Study of Atherosclerosis (MESA).

METHODS

Retinal photographs were obtained with a 45 degrees nonmydriatic digital fundus camera. Presence and severity of diabetic retinopathy were graded at a central reading center on the basis of a modification of the Airlie House classification system. All participants underwent a standardized interview, examination, and laboratory investigations.

RESULTS

In this population with diabetes, the prevalence of any retinopathy was 33.2% and macular edema 9.0%. The prevalence of any diabetic retinopathy and macular edema was significantly higher in blacks (36.7% and 11.1%) and hispanics (37.4% and 10.7%) than in whites (24.8% and 2.7%) and chinese (25.7% and 8.9%) (P = .01 and P = .007, comparing racial/ethnic differences for retinopathy and macular edema, respectively). Significant independent predictors of any retinopathy were longer duration of diabetes, higher fasting serum glucose, use of diabetic oral medication or insulin, and greater waist-hip ratio. Race was not an independent predictor of any retinopathy.

CONCLUSIONS

This study provides contemporary data on the prevalence of and risk factors for diabetic retinopathy among whites, blacks, hispanics, and chinese participating in the MESA.

Retinal hemodynamics in early diabetic macular edema

The objective of this study was to establish the baseline retinal hemodynamic characteristics of stratified groups of diabetic patients at increasing risk for the development of diabetic macular edema (DME). Group 1 had 50 control subjects, group 2 had 56 diabetic patients without clinically visible retinopathy, group 3 had 54 diabetic patients with microaneurysms and/or hard exudates within two disc diameters of the fovea in the absence of clinically manifest DME, and group 4 had 40 patients with clinically manifest DME. Retinal hemodynamics (diameter, velocity, maximum-to-minimum velocity ratio, and flow) were assessed. Intraocular pressure, blood pressure, and relevant systemic markers of diabetes control and complications were also undertaken. The maximum-to-minimum velocity ratio was elevated with increasing risk of clinically significant DME (P < 0.0001). No significant differences were found between the groups with respect to diameter, velocity, or flow. The maximum-to-minimum velocity ratio was correlated to age, duration of diabetes, blood pressure, pulse rate, intraocular pressure, and serum potassium levels. In conclusion, the maximum-to-minimum velocity ratio was significantly increased with increasing risk of development of DME. Retinal arteriolar hemodynamics were positively correlated to age, duration of diabetes, and blood pressure. These findings suggest a reduction in the compliance (i.e., an increase of vascular rigidity) of the arteriolar circulation with increasing risk of DME.

Retinopathy screening in individuals with type 2 diabetes: who, how, how often, and at what cost—an epidemiologic review

BACKGROUND

Despite treatment regimens, which can reduce blindness, diabetic retinopathy remains the leading cause of irreversible blindness for persons less than 75 years. Screening for diabetic retinopathy in type 1 diabetes mellitus has proven to be both efficacious and cost effective. Although treatment has been shown to be equally efficacious for type 2 diabetes, the effectiveness and cost benefit of screening are less clear.

METHODS

A systematic review of the recent literature on the epidemiology of retinopathy in type 2 diabetics was carried out. Specific issues related to the changing epidemiology of diabetes and diabetic retinopathy, as well as the effectiveness, and cost benefit of screening were evaluated.

CONCLUSIONS

Diabetic retinopathy is at the convergence of several epidemiologic trends. Although the prevalence of diabetic retinopathy within the population of diagnosed diabetics may be decreasing because of aggressive risk factor reduction, any gains achieved are likely to be negated by the large increase in the prevalence of type 2 diabetes in the population owing to obesity. The epidemiology findings suggest that certain persons with well-controlled type 2 diabetes may not warrant yearly examination for diabetic retinopathy; however, given the low percentage of diabetics who are currently screened for retinopathy, it would seem unwise to recommend changes in the timing of examination. Evidence appears to suggest that photoscreening is a viable alternative to a screening examination.

Ethnicity, race, and baseline retinopathy correlates in the veterans affairs diabetes trial

OBJECTIVE

The Veterans Affairs Diabetes Trial (VADT) cohort is enriched with approximately 20% Hispanics and 20% African Americans, affording a unique opportunity to study ethnic differences in retinopathy.

RESEARCH DESIGN AND METHODS

Cross-sectional analyses on the baseline seven-field stereo fundus photos of 1,283 patients are reported here. Diabetic retinopathy scores are grouped into four classes of increasing severity: none (10-14), minimal nonproliferative diabetic retinopathy (NPDR) (15-39), moderate to severe NPDR (40-59), and proliferative diabetic retinopathy (60+). These four groups have also been dichotomized to none or minimal (10-39) and moderate to severe diabetic retinopathy (40+).

RESULTS

The prevalence of diabetic retinopathy scores >40 was higher for Hispanics (36%) and African Americans (29%) than for non-Hispanic whites (22%). The difference between Hispanics and non-Hispanic whites was significant (P < 0.05). Similarly, the prevalence of diabetic retinopathy scores >40 was significantly higher in African Americans than in non-Hispanic whites (P < 0.05). These differences could not be accounted for by an imbalance in traditional risk factors such as age, duration of diagnosed diabetes, HbA(1c) (A1C), and blood pressure. Diabetic retinopathy severity scores were also significantly associated with increasing years of disease duration, A1C, systolic and diastolic blood pressure, the degree of microalbuminuria, fibrinogen, and the percentage of patients with amputations. There was no relationship between retinopathy severity and the percentage of people who had strokes or cardiac revascularization procedures. There was an inverse relationship between retinopathy severity and total cholesterol, triglycerides, and plasminogen activator inhibitor-1 as well as with smoking history. Diabetic retinopathy scores were not associated with age.

CONCLUSIONS

In addition to many well-known associations with retinopathy, a higher frequency of severe diabetic retinopathy was found in the Hispanic and African-American patients at entry into the VADT that is not accounted for by traditional risk factors for diabetic retinopathy, and these substantial ethnic differences remain to be explained.