Glycaemic control and control of risk factors in diabetes patients in an ophthalmology clinic: what lessons have we learned from the UKPDS and DCCT studies?

FreeStyle Libre Flash Glucose Monitoring system for people with type 1 diabetes in the UK: a budget impact analysis

INTRODUCTION

This study aims to estimate the budget impact of increased uptake of the FreeStyle Libre Flash Glucose Monitoring system in people with type 1 diabetes mellitus (T1DM) in the UK.

RESEARCH DESIGN AND METHODS

A budget impact model was developed, applying real-world data collected in the Association of British Clinical Diabetologists (ABCD) FreeStyle Libre Nationwide Audit. Costs of diabetes glucose monitoring in a T1DM population (n=1790) using self-monitoring of blood glucose (SMBG) or the FreeStyle Libre system were compared with a scenario with increased use of the FreeStyle Libre system.

RESULTS

The ABCD audit demonstrates FreeStyle Libre system use reduces diabetes-related resource utilization. The cost analysis found that higher acquisition costs are offset by healthcare costs avoided (difference £168 per patient per year (PPPY)). Total costs were £1116 PPPY with FreeStyle Libre system compared with £948 PPPY with SMBG. In an average-sized UK local health economy, increasing FreeStyle Libre system uptake from 30% to 50% increased costs by 3.4% (£1 787 345-£1 847 618) and when increased to 70% increased by a further 3.3%.

CONCLUSION

Increased uptake of the FreeStyle Libre system in the T1DM population marginally increases the cost to UK health economies and offers many system benefits.

Diabetic retinopathy and visual impairment in a Norwegian diabetic coast population with a high dietary intake of fish oils. An observational study

PURPOSE

To present retinal and visual findings in a Norwegian west coast diabetic population and to elucidate the effect of dietary intake of marine polyunsaturated fatty acids (PUFAs) on the development of diabetic retinopathy (DR).

METHODS

In an eye practice in an archipelago of 314 km², serving a population of about 40 000, we recorded the prevalence of visual impairment and DR in a referred diabetic population. 510 consecutive patients were included, 238 females and 272 males. 50 patients had type I and 460 had type II diabetes mellitus (DM). Self-reported medication, diet supplements, HbA1c and fish consumption were registered.

RESULTS

In the type I group, the median age was 44.5 and median DM duration 11.5 years [1-44]. 48% had photographic evidence of DR, 8 patients (16%) had proliferative retinopathy (PDR), and 6 patients (12%) had diabetic macular oedema (DME). All had best-corrected visual acuity (BCVA) of 0.5 (log MAR 0.3) or better in the best eye. In the type II group, the median DM duration was 8 years [1-53], and median age was 66. 98% had best eye BCVA at or better than 0.5 (log MAR 0.3) in the best eye.

CONCLUSION

None of the 510 patients had BCVA worse than 0.3 (log MAR 0.48) due to diabetic retinopathy. Compared to similar studies, we found a very low visual impairment rate. A possible protective effect of PUFA on the prevalence and progression of diabetic microangiopathy including retinopathy is discussed.

Life Style Intervention Improves Retinopathy Status-The Finnish Diabetes Prevention Study

The aim of the study was to find out whether participation in earlier intervention had an effect on the occurrence of retinopathy in study participants. We also examined risk factors (age, sex, weight, fasting and 2 h glucose, fasting insulin, blood pressure, serum lipids) for early retinal changes. The study included 522 individuals (mean 55 years old, range 40-64 years) with impaired glucose tolerance who were randomized into intervention (weight loss, healthy diet, and physical activity, N = 265) and control groups (N = 257). Intervention lasted for median of four years in 1993-2000, after which annual follow-up visits at study clinics were conducted. In the years 2002-2006 (at least five years after stopping intervention), fundus photography was offered for all study participants in four of five study clinics. Photographs were assessed by two experienced ophthalmologists (A.A. and K.K.), masked for the group assignment. After exclusion of poor quality photographs, the data of 211 individuals (N = 113 for intervention and N = 98 for control group) were included in the present study. The occurrence of microaneurysms was significantly higher in the control (37/98, 38%) than in the intervention group (27/113, 24%; p = 0.029). In the model, including age, sex, diabetes diagnosis before the retinal assessment, body mass index (BMI), and treatment group, the odds ratio for microaneurysms was markedly lower in intervention group (OR 0.52; 0.28-0.97, p = 0.039). The only risk factor that predicted the occurrence of microaneurysms was serum triglycerides at baseline (mean ± SD 1.9 ± 0.9 vs. 1.6 ± 0.7, mmol/L, with and without microaneurysms, respectively, p = 0.003). Triglycerides associated with decreased microaneurysms in regression analysis for age, sex, fasting glucose, and intervention group (OR 1.92, p = 0.018). Lifestyle intervention in overweight and obese individuals with impaired glucose tolerance showed decreased occurrence of retinal microaneurysms. Elevated serum triglycerides were associated to the development of early diabetic microangiopathy.

Glycaemic control in diabetic patients in Zambia

INTRODUCTION

The glycaemic control status of diabetic patients affects the management of their disorder. We examined the glycaemic control and clinical factors that may influence the achievement of the glycaemic control targets among diabetic out-patients.

METHODS

This was a hospital based cross-sectional study carried out at the University Teaching Hospital diabetic clinic in Lusaka, Zambia. A simple random sample of 198 consenting participants was selected from diabetic out-patients between September and December 2013. A structured interview schedule was used to capture socio-demographic data as well as needed clinical data from clients' medical records and laboratory results. Multivariate binary logistic regression analysis was carried out to examine factors that may be associated with the glycaemic control status of these diabetic patients.

RESULTS

Overall (n = 198), mean (SD) age was 53.19 ± 13.32 years. Majority (61.3%) of the patients had poor glycaemic control status (HbA1c ≥ 49 mmol/mol). Insulin treatment (OR 0.13, 95% CI: 0.01 - 1.41), systolic blood pressure (OR 1.04, CI: 1.00 - 1.08) and fasting plasma glucose (previous; OR 0.81, CI: 0.72 - 0.90 and current; OR 0.85, CI: 0.78 - 0.93) were statistically significantly associated with glycaemic control. The poor glycaemic control observed in this study is similar to that reported in other published studies.

CONCLUSION

We found evidence of poor glycaemic control in the study population suggesting need to explore the reasons for this. Association of Insulin, systolic blood pressure and fasting plasma glucose with glycaemic control further suggests the efficiency of traditional basic monitoring parameters which should be exploited in sharpening primary preventive strategies especially those that support lifestyle modification. Such efforts should also be integrated in all information, education and communication strategies that target but not limited to hospital based patients too.

Prevalence of hypertension and obesity in patients with type 2 diabetes mellitus in observational studies: a systematic literature review

BACKGROUND

Hypertension and obesity are known to contribute, directly or indirectly, to the development of long-term complications of type 2 diabetes mellitus (T2DM). Knowing the prevalence of these comorbidities is important for determining the size of the population that may benefit from strategies that reduce blood pressure and weight while controlling blood glucose.

METHODS

In this systematic literature review, electronic searches of PubMed, Embase, and the Cochrane Library were conducted to identify observational studies of hypertension and/or obesity prevalence in patients with T2DM throughout the world. The searches were limited to studies reported in English from January 1, 2001 to February 16, 2012.

RESULTS

From a total of 2,688 studies, 92 observational studies provided prevalence rates for hypertension and/or obesity specifically in adults with T2DM. Fifteen studies of specific subtypes of hypertension or subpopulations with T2DM were subsequently excluded, leaving 78 studies (in 77 articles) for inclusion in this article. Of these, 61studies reported hypertension prevalence, 44 reported obesity prevalence, and 12 reported the prevalence of hypertension with obesity. Most studies had a low risk of bias regarding diagnosis of T2DM (70/78), hypertension (59/69), or obesity (45/47). The continental regions with the most observational studies of hypertension or obesity prevalence were Europe (n = 30) and Asia (n = 26). Hypertension rates typically were high in all regions; most studies presented rates above 50%, and many presented rates above 75%. Obesity rates exceeded 30% in 38 of 44 studies and 50% in 14 of 44 studies, especially those assessing central obesity (based on waist circumference). Among obese adults, hypertension rates were at or above 70% in Asia and above 80% in Europe; rates were lower in North and South America but still above 30%.

CONCLUSION

Around the world, hypertension and obesity, separately or together, are common comorbidities in adults with T2DM.

Association analysis of genetic variations of eNOS and α2β1 integrin genes with type 2 diabetic retinopathy

Background

Diabetic retinopathy (DR) is classically defined as a microvasculopathy that primarily affects the small blood vessels of the inner retina as a complication of diabetes mellitus. It has been suggested that nitric oxide (NO) and α₂β₁ integrin (a platelet receptor for collagen) play an important role in the pathogenesis of microvascular complications in DR.

Aim

The aim of this study was to investigate the association of two candidate genes involved in the regulation of retinal vasculature, endothelial nitric oxide synthase (eNOS) and α₂β₁ integrin (ITGA2) genes, with the development of DR in Egyptian patients with type 2 diabetes mellitus and to investigate whether genetic variants will affect the type of retinopathy (proliferative or nonproliferative).

Methods

In this study, 70 patients were enrolled and categorized into two groups: (1) a DR group consisting of 50 patients with DR, which was further subclassified into 25 patients with nonproliferative DR (NPDR group) and 25 patients with proliferative DR (PDR group) and (2) a diabetes without retinopathy (DWR) group, comprising 20 patients with type 2 diabetes of more than 10 years’ duration who showed no signs of DR. Associations of the genetic polymorphisms of eNOS (G894T) and ITGA2 (BgI II) were studied. Polymerase chain reaction-restriction fragment length polymorphism analysis was performed for all samples to evaluate the genotypes and correlate with the phenotype of the disease.

Results

The allele frequencies of both polymorphisms showed considerable differences between patients with and without DR. The GG genotype of G894T polymorphism of eNOS was associated with a 9.75-fold increased risk of DR (95% confidence interval 1.7–55.4) and the genotype ITGA2 BgI II (+/+) was associated with a 10.1-fold increased risk of DR (95% confidence interval 1.8–57.9), while the α₂β₁ integrin gene polymorphism of genotype distribution of both eNOS and ITGA2 polymorphisms did not differ significantly between the proliferative and nonproliferative DR groups.

Conclusion

A significant association between the G894T polymorphism of eNOS and BgI II polymorphism of ITGA2 genes and DR was observed, while there was no association between the genetic variants of those two polymorphisms and the type of retinopathy.

Associations between chronic glycosylated haemoglobin (HbA1c) level and macular volume in diabetes patients without macular oedema

PURPOSE

This study aimed to examine the correlation between glycosylated haemoglobin (HbA1c) level and macular volume in diabetes patients without diabetic macular oedema (DMO).

METHODS

We carried out an observational, cross-sectional study. Patients who had diabetes mellitus (DM) of ≥ 10 years duration without DMO were included. Only one eye of each patient was selected for analysis. Eyes with proliferative diabetic retinopathy were excluded. Central subfield thickness (CST), central subfield volume (CSV) and total macular volume (TMV) were measured by optical coherence tomography (OCT). Chronic HbA1c level was defined as the mean HbA1c value in the year prior to enrolment.

RESULTS

We included 97 eyes from 97 patients (47 women, 50 men; mean age 62.2 years). They included eight type 1 and 89 type 2 DM patients. The mean duration of DM was 15.5 years. Forty-two (43%) eyes had no diabetic retinopathy and 55 (57%) eyes had non-proliferative diabetic retinopathy. In statistical analysis, CST (mean 188.80 ± 27.64 μm; r = 0.220, p = 0.030), CSV (mean 0.149 ± 0.021 mm(3) ; r = 0.213, p = 0.036) and TMV (mean 6.497 ± 0.715 mm(3) ; r = 0.299, p = 0.003) positively correlated with chronic HbA1c level (7.95 ± 1.29%). The linear regression model showed that chronic HbA1c level (standardized coefficient 0.253; p = 0.013) and age (standardized coefficient - 0.206; p = 0.040) were factors significantly related to TMV.

CONCLUSIONS

Chronic HbA1c level positively correlates with macular thickness and volume in patients with DM of ≥ 10 years duration without DMO. Our results suggest that subclinical macular volume and thickness changes may occur before DMO becomes clinically evident. Early tight glycaemic control prior to the onset of DMO may play an important role in preventing the deterioration of macular function by altering macular haemodynamics.

Risk of retinal neovascularization in the second eye in patients with proliferative diabetic retinopathy

PURPOSE

This study aimed to evaluate the risk of proliferative diabetic retinopathy (DR) in the fellow eye of an eye with existing proliferative DR.

METHODS

Our DR screening programme database listed 1513 diabetes patients alive at the time of the study. Seventy-six had proliferative DR in one or both eyes.

RESULTS

In 28 of the 76 (37%) diabetes patients, proliferative DR was diagnosed in both eyes at the same examination. Another 28 patients developed proliferative DR in the second eye within 5 years of its diagnosis in the first eye, bringing the total number of diabetes patients with proliferative DR in both eyes at 5 years to 56 (74%). Almost all the diabetes patients eventually developed proliferative DR in the second eye. The median duration of diabetes before the development of proliferative retinopathy was 19 years for type 1 and 14 years for type 2 diabetes.

CONCLUSIONS

Proliferative DR is a bilateral disease. Diabetes patients with proliferative DR in one eye are at high risk of developing neovascularization in the second eye and close follow-up is recommended.

The consequences of delaying insulin initiation in UK type 2 diabetes patients failing oral hyperglycaemic agents: a modelling study

BACKGROUND

Recent data have shown that type 2 diabetes patients in the UK delay initiating insulin on average for over 11 years after first being prescribed an oral medication. Using a published computer simulation model of diabetes we used UK-specific data to estimate the clinical consequences of immediately initiating insulin versus delaying initiation for periods in line with published estimates.

METHODS

In the base case scenario simulated patients, with characteristics based on published UK data, were modelled as either initiating insulin immediately or delaying for 8 years. Clinical outcomes in terms of both life expectancy and quality-adjusted life expectancy and also diabetes-related complications (cumulative incidence and time to onset) were projected over a 35 year time horizon. Treatment effects associated with insulin use were taken from published studies and sensitivity analyses were performed around time to initiation of insulin, insulin efficacies and hypoglycaemia utilities.

RESULTS

For patients immediately initiating insulin there were increases in (undiscounted) life expectancy of 0.61 years and quality-adjusted life expectancy of 0.34 quality-adjusted life years versus delaying initiation for 8 years. There were also substantial reductions in cumulative incidence and time to onset of all diabetes-related complications with immediate versus delayed insulin initiation. Sensitivity analyses showed that a reduced delay in insulin initiation or change in insulin efficacy still demonstrated clinical benefits for immediate versus delayed initiation.

CONCLUSION

UK type 2 diabetes patients are at increased risk of a large number of diabetes-related complications due to an unnecessary delay in insulin initiation. Despite clear guidelines recommending tight glycaemic control this failure to begin insulin therapy promptly is likely to result in needlessly reduced life expectancy and compromised quality of life.

Endothelial cell inhibitory autoantibodies are associated with laser photocoagulation in adults from the Veterans Affairs Diabetes Trial

Basic fibroblast growth factor (bFGF) is a potent endothelial cell mitogen that does not normally circulate, but increases in microalbuminuric adult type 2 diabetes mellitus. Earlier work indicated an unexpected association between low levels of plasma bFGF immunoreactivity and the subsequent 4-year need for laser treatment in 172 patients from the Veterans Affairs Diabetes Trial (mean: age, 59 years; diabetes duration, 11 years; baseline hemoglobin A(1c), 9.5%). In the present study, we tested for an association between endothelial cell inhibitory autoantibodies in plasma and the need for laser treatment. Inhibitory activity in endothelial cells from the immunoglobulin G fractions of plasma was significantly associated (P = .002) with low plasma bFGF immunoreactivity. There was a significant association (P = .003) between endothelial cell inhibitory autoantibodies in baseline plasma and the time to occurrence of first laser treatment after 4 years of study treatment. After adjusting for other risk factors, endothelial cell inhibitory activity greater than 90% vs less than or equal to 90% (hazard ratio, 0.2; P = .003) and low-density lipoprotein cholesterol concentration (hazard ratio, 0.98; P = .02) were each significant predictors of the time to first postrandomization laser occurrence. These results suggest that circulating autoantibodies inhibitory in endothelial cells may contribute to the need for laser treatment in adult men with advanced type 2 diabetes mellitus. Among the possible risk factors evaluated, baseline insulin use was the only variable significantly inversely (P = .02) associated with the baseline occurrence of inhibitory endothelial cell autoantibodies. It could not be determined whether insulin use may decrease the occurrence of endothelial cell inhibitory autoantibodies in advancing adult type 2 diabetes mellitus.

Measuring the refractive properties of the diabetic eye during blurred vision and hyperglycaemia using aberrometry and Scheimpflug imaging

PURPOSE

This study aimed to measure the refraction and geometry in the diabetic eye during the presence and absence of hyperglycaemia and blurred vision, using aberrometry and Scheimpflug imaging.

METHODS

Aberrometry and Scheimpflug imaging were used to examine ocular refraction and higher-order aberrations, as well as the shape of the cornea and the lens, in 25 patients with diabetes mellitus. From these parameters, the equivalent refractive index of the lens was calculated. Using paired t-tests, comparisons were made between a first series of measurements (Visit 1) taken in the presence of blurred vision and hyperglycaemia (> 10.0 micromol/l), and a second series of measurements (Visit 2) taken under normal conditions.

RESULTS

The mean difference in blood glucose between Visits 1 and 2 was 5.9 mmol/l (standard deviation [SD] 3.1) (p < 0.0001). Both small hyperopic and myopic shifts of equivalent refractive error (ERE) were found in nine patients (mean absolute difference ERE: 0.38 D [SD 0.12]; p = 0.02). Furthermore, higher-order aberrations (root mean square [RMS] error) were slightly increased in four patients (mean difference RMS error: 0.07 microm [SD 0.02]; p = 0.04) at Visit 1, compared to Visit 2. No significant changes were observed in the shape of the cornea or lens in any of the patients. No significant correlations were found between changes in blood glucose levels and the measured parameters in diabetic eyes.

CONCLUSIONS

The present study suggests that subjective symptoms of blurred vision during hyperglycaemia are not necessarily caused by changes in the refractive properties of the diabetic eye.

Low plasma basic fibroblast growth factor is associated with laser photocoagulation treatment in adult type 2 diabetes mellitus from the Veterans Affairs Diabetes Trial

Basic fibroblast growth factor (bFGF) is a potent endothelial cell mitogen that does not normally circulate. Yet plasma bFGF-like bioactivity was increased in association with persistent microalbuminuria and retinopathy in adult type 2 diabetes mellitus. In the present study, we tested whether plasma bFGF immunoreactivity (IR) could predict the need for laser treatment of diabetic retinopathy in a baseline subset of advanced type 2 diabetes mellitus from the Veterans Affairs Diabetes Trial (mean: age, 59 years; diabetes duration, 11 years; baseline glycosylated hemoglobin, 9.5%). Plasma bFGF-IR was determined with a sensitive and specific 2-site enzyme-linked immunoassay in 172 patients at the baseline visit. Results were dichotomized at 4.5 pg/mL, the upper limit in healthy men. There was an unexpected significant association between low baseline plasma bFGF-IR level and the interim (4 years) need for laser treatment. First laser treatment was significantly more likely to be required in patients with low compared with high baseline bFGF (19% vs 6%, P = .03 for the difference). After adjusting for clinical risk factors, low vs high bFGF (hazard ratio [HR], 5.01; P = .012), duration of diabetes (HR, 1.05; P = .050), and low-density lipoprotein cholesterol concentration (HR, 0.98; P = .027) were all significantly associated with time to first laser occurrence. These and our prior results suggest that low plasma bFGF-IR may be a marker for the presence of anti-endothelial cell autoantibodies that may contribute to the need for laser photocoagulation treatment in adult men with advanced type 2 diabetes mellitus.

Regular visits to a diabetes clinic were associated with lower magnitude of visual disability and diabetic retinopathy-a hospital-based historical cohort study in yemen

BACKGROUND

We associated regularity in visits to a diabetes clinic with the presence of diabetic retinopathy (DR) and visual disabilities.

METHODS

This historical cohort study was conducted in 2004. The physician reported details of diabetes mellitus (DM), hypertension, and other illness. The ophthalmologist examined eyes and noted visual acuity, DR, and other ocular morbidities. We calculated the relative risk (RR) of different complications of diabetes.

RESULTS

Our cohort consisted of 228 patients (114 in each group, one that attended diabetes clinics regularly [group A] and one that had irregular attendance [group B]). DR was found in 47 (41.2%) and 68 (61.4%) patients, respectively. The risk of DR was significantly higher in group B (RR = 1.51, 95% confidence interval [CI] 1.23 to 2.18). The severity of DR was also positively associated with irregularity in clinic visits (x(2) = 33.56, degrees of freedom = 5, P = 0.000003). The risk of bilateral blindness (RR = 4.0, 95% CI 1.38 to 11.6) and low vision disability (RR = 2.53, 95% CI 1.84 to 3.47) were higher in group B. The duration of diabetes and the regularity in clinic visits were the predictors of DR.

CONCLUSIONS

The presence of DR and visual disabilities among patients with diabetes is associated with irregular attendance at diabetes clinics. The regularity of medical visits seems to be a proxy indicator of better primary prevention of eye complications of DM.

Physiology of vitreous surgery

Vitreous surgery has various physiological and clinical consequences, both beneficial and harmful. Vitrectomy reduces the risk of retinal neovascularization, while increasing the risk of iris neovascularization, reduces macular edema and stimulates cataract formation. These clinical consequences may be understood with the help of classical laws of physics and physiology. The laws of Fick, Stokes-Einstein and Hagen-Poiseuille state that molecular transport by diffusion or convection is inversely related to the viscosity of the medium. When the vitreous gel is replaced with less viscous saline, the transport of all molecules, including oxygen and cytokines, is facilitated. Oxygen transport to ischemic retinal areas is improved, as is clearance of VEGF and other cytokines from these areas, thus reducing edema and neovascularization. At the same time, oxygen is transported faster down a concentration gradient from the anterior to the posterior segment, while VEGF moves in the opposite direction, making the anterior segment less oxygenated and with more VEGF, stimulating iris neovascularization. Silicone oil is the exception that proves the rule: it is more viscous than vitreous humour, re-establishes the transport barrier to oxygen and VEGF, and reduces the risk for iris neovascularization in the vitrectomized-lentectomized eye. Modern vitreous surgery involves a variety of treatment options in addition to vitrectomy itself, such as photocoagulation, anti-VEGF drugs, intravitreal steroids and release of vitreoretinal traction. A full understanding of these treatment modalities allows sensible combination of treatment options. Retinal photocoagulation has repeatedly been shown to improve retinal oxygenation, as does vitrectomy. Oxygen naturally reduces VEGF production and improves retinal hemodynamics. The VEGF-lowering effect of photocoagulation and vitrectomy can be augmented with anti-VEGF drugs and the permeability effect of VEGF reduced with corticosteroids. Starling's law explains vasogenic edema, which is controlled by osmotic and hydrostatic gradients between vessel and tissue. It explains the effect of VEGF-induced vascular permeability changes on plasma protein leakage and the osmotic gradient between vessel and tissue. At the same time, it takes into account hemodynamic changes that affect the hydrostatic gradient. This includes the influence of arterial blood pressure, and the effect oxygen (laser treatment) has in constricting retinal arterioles, increasing their resistance, and thus reducing the hydrostatic pressure in the microcirculation. Reduced capillary hydrostatic pressure and increased osmotic gradient reduce water fluxes from vessel to tissue and reduce edema. Finally, Newton's third law explains that vitreoretinal traction decreases hydrostatic tissue pressure in the retina, increases the pressure gradient between vessel and tissue, and stimulates water fluxes from vessel into tissue, leading to edema.