Glycemic control and development of retinopathy in youth-onset insulin-dependent diabetes mellitus. Results of a 12-year longitudinal study

The association of the serum levels of aldehydes with diabetes-related eye diseases: a cross-sectional population-based study

Diabetes could impact many ocular tissues. However, the association of the serum aldehydes with diabetes-related eye diseases (DED) remains unclear. Thus, we aimed to examine the above relationship from the general US population of 2013-2014 National Health and Nutrition Examination Survey (NHANES). The multivariable logistic regression and Bayesian kernel machine regression (BKMR) were used to analyze the effect of serum aldehydes on the risk of DED. Pearson's correlation analysis, the restricted cubic spline (RCS) model, and the linear regression were performed to explore the association between the serum aldehydes and other parameters. The multivariable linear regression was conducted to further underlie the relationship between the serum aldehydes and the glycohemoglobin A1c (HbA1c) in DED participants. Although no significant association was observed between the serum aldehydes and the risk of DED by the multivariable logistic regression and BKMR, the Pearson correlation revealed a positive association between the HbA1c level and the serum level of heptanaldehyde and isopentanaldehyde in DED participants. The RCS model confirmed the above linear correlation. After adjusting for the cofounding factor of smoking, the multivariable linear regression revealed a significant association between the serum level of heptanaldehyde and the HbA1c level in DED participants. Our results suggest that aldehyde exposure did not significantly increase the risk of DED, while heptanaldehyde was the risk factor for increased HbA1c in DED population.

Pathological eating behaviours and risk of retinopathy in diabetes: a systematic review and meta-analysis

Background

Diabetes mellitus can cause several long-term macrovascular and microvascular complications including nephropathy, neuropathy, and retinopathy (DR). Several studies have reported positive associations between eating pathologies and DR; however, these studies have not been aggregated and sub-grouped into type of pathological eating behaviour, and the differences in risk according to type of eating behaviour is unknown. The aim of this review, therefore, was to aggregate risks of DR in populations with and without pathological eating behaviours, stratified according to eating behaviour.

Methods

A systematic review and meta-analysis was conducted. Major databases and grey literature were search from inception until 1/6/2021. Studies reporting the prevalence of pathological eating behaviours (against a control group with no pathological eating behaviours) in diabetic people with and without DR were included. Odds ratios were calculated from primary data.

Results

Seven studies with eight independent outcomes with a total of 1162 participants were included. The odds ratio of DR in the total pooled analysis was 2.94 (95%CI 1.86-4.64; p = <0.001; I2 = 29.59). Two types of eating behaviour yielded enough data for sub-group analysis. Eating disorder not otherwise specified yielded an odds ratio of 2.73 (95%CI 1.81-4.10; p = <0.001; I2 = 0.00), and binge eating disorder yielded an non-significant odds ratio of 0.92 (95%CI 0.31-2.77; p = 0.887;I2 = 0.00).

Discussion

The likelihood of DR increases almost three times in the presence of pathological eating behaviours. More studies are required to confirm this in clinical populations stratified by eating disorder. Practitioners working with people with diabetes should closely monitor eating behaviours to preclude this risk.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-022-00980-x.

Patient perspectives on peer mentoring: type 1 diabetes management in adolescents and young adults

PURPOSE

The purpose of the study was to identify attitudes and topics relevant to peer mentoring as an adherence-promoting intervention for adolescents and young adults (YAs) with type 1 diabetes (T1D).

METHODS

Self-administered survey data were collected in 2 diabetes clinics from a convenience sample of adolescents as prospective mentees (ages 13-18) and YAs as prospective mentors (ages 19-25) with T1D. Survey topics included demographics, disease history, glycemic control, adherence, depression, barriers to disease management, social support, and interest in peer mentoring. Descriptive statistical analyses, thematic coding, and stepwise multivariate logistic regression were performed.

RESULTS

A majority of the 54 adolescents and 46 YAs expressed interest in a peer mentoring program. Having supportive friends and living in a large household positively predicted adolescent interest in having a peer mentor. Approximately one-third of all participants experienced social barriers to diabetes management. For adolescents, barriers included inflexible schedules, unfamiliar foods, and the embarrassment of checking blood glucose in front of others. Young adults reported barriers in tracking food consumption and remembering to check blood glucose. Various diabetes management skills were in high demand by adolescents, who especially desired to learn about managing T1D on their own and in college. Participants were open to multiple communication modes, including in-person meetings, phone, text messaging, and social media.

CONCLUSIONS

Many adolescents and young adults with T1D are interested in peer mentoring as a way to facilitate learning and sharing essential diabetes management skills and experiences.

Retinopathy screening in patients with type 1 diabetes diagnosed in young age using a non-mydriatic digital stereoscopic retinal imaging

BACKGROUND

Diabetic retinopathy seriously impairs patients' quality of life, since it represents the first cause of blindness in industrialized countries.

AIM

To estimate prevalence of retinopathy in young Type 1 diabetes patients using a non-mydriatic digital stereoscopic retinal imaging (NMDSRI), and to evaluate the impact of socio-demographic, clinical, and metabolic variables.

SUBJECTS AND METHODS

In 247 young patients glycated hemoglobin (HbA1c), gender, age, pubertal stage, presence of diabetic ketoacidosis (DKA), HLA-DQ heterodimers of susceptibility for Type 1 diabetes, and β-cell autoimmunity at clinical onset were considered. At retinopathy screening, we evaluated age, disease duration, pubertal stage, body mass index (BMI-SDS), insulin requirement, HbA1c levels, other autoimmune diseases, diabetes-related complications, serum concentrations of cholesterol and triglycerides, systolic and diastolic blood pressure.

RESULTS

Retinopathy was found in 26/247 patients: 25 showed background retinopathy, and 1 had a sight-threatening retinopathy. A significant relationship between retinopathy and female gender (p=0.01), duration of disease ≥15 yr (p<0.0001), serum triglycerides levels >65 mg/dl (p=0.012) and mean HbA1c ≥7.5% or >9% (p=0.0014) were found at the multivariate logistic analysis.

CONCLUSIONS

Metabolic control is the most important modifiable factor and promotion of continuous educational process to reach a good metabolic control is a cornerstone to prevent microangiopathic complications. Symptoms appear when the complication is already established; a screening program with an early diagnosis is mandatory to prevent an irreversible damage.

Growth hormone hypothesis and development of diabetic nephropathy in Type 1 diabetes

In Type 1 diabetes, poor glycemic control is the key predictor for the development of microalbuminuria, an established early marker of overt nephropathy. However, the role of other pathways in the development of diabetic nephropathy may also be important. The growth hormone (GH) hypothesis suggests that the GH-insulin-like growth factor (IGF)-1 axis may play an important role in this disease process. In Type 1 diabetes, the characteristic pattern of GH hypersecretion and low circulating IGF-1 levels results from hepatic GH resistance owing to the lack of portal insulin. Clinical data indicate that high GH and low IGF-1 levels reduce insulin sensitivity and worsen glycemic control. Furthermore, despite hepatic GH resistance, GH receptors at the kidney remain intact. Experimental data show that excess GH stimulates renal GH receptors and, through paracrine IGF-1 production, results in pathophysiological changes consistent with diabetic nephropathy, namely nephromegaly, glomerular hyperfiltration and eventual proteinuria. These abnormalities are reversed by intervention to block or normalize the local effects of GH and IGF-1. Although such data in humans are limited, preliminary trials show that interventions to increase IGF-1 levels and reduce GH hypersecretion improve glycemic control and insulin sensitivity in the short term. However, their effects on early nephropathy and end points, such as the prevalence of end stage renal disease, have yet to be determined.

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

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

A Review of Types 1 and 2 Diabetes Mellitus and Their Treatment with Insulin

Diabetes is a chronic disease characterized by hyperglycemia, and the prevalence of type 2 diabetes is growing to epidemic proportions in certain populations. Type 1 diabetes is primarily the result of autoimmune destruction of beta cells. Type 2 diabetes is found in those with resistance to the action of insulin, usually as a result of obesity, and deficient insulin secretion. Insulin use not only prevents hyperglycemic emergencies, but also is the best safeguard to prevent the long-term complications of diabetes by correcting fasting and postprandial hyperglycemia. Intensive glycemic control can lead to a substantial decrease in the development of microvascular changes found in patients with diabetes. Human insulin analogs, insulins manufactured by recombinant technology which contain substituted or rearranged amino acids, allow more physiological patterns of insulin replacement, termed the basal-bolus approach. Serious hypoglycemia is the biggest obstacle for patients with diabetes treated with intensive insulin programs. Insulin is now available in prefilled pens or can be delivered by a programmable pump to allow greater flexibility in use and to improve glycemic control. Whereas hyperglycemic emergencies are usually treated with intravenous fluids and an intravenous continuous insulin infusion, patients who are less critically ill can be treated with fluid and subcutaneous insulin analogs.

Funduscopic findings following cataract extraction by means of phacoemulsification in diabetic dogs: 52 cases (1993-2003)

OBJECTIVE

To determine prevalence of retinal hemorrhages and microaneurysms in dogs with diabetes mellitus following cataract extraction by means of phacoemulsification and identify potential risk factors.

DESIGN

Retrospective study.

PROCEDURE

Medical records of dogs undergoing phacoemulsification between 1993 and 2003 were reviewed, and information was recorded on signalment, history, physical examination findings, ophthalmic examination findings, results of laboratory testing, electroretinographic findings, and surgical findings. Glycemic control was classified as poor, intermediate, or good on the basis of baseline blood glucose concentration, perioperative body weight loss, daily insulin dosage, and presence of glucosuria and ketonuria. Data from diabetic and nondiabetic dogs were analyzed to determine prevalence and risk factors for development of retinal hemorrhages or microaneurysms following phacoemulsification.

RESULTS

11 of the 52 (21%) dogs with diabetes mellitus developed ophthalmoscopic signs of retinal hemorrhages or microaneurysms, compared with 1 of the 174 (0.6%) nondiabetic dogs. Median time from onset of diabetes mellitus to diagnosis of retinopathy was 1.4 years (range, 0.5 to 3.2 years). No risk factors for development of retinopathy were identified.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that retinal hemorrhages and microaneurysms may be more common and develop earlier in diabetic dogs than previously reported. This may affect treatment, as diabetic dogs survive longer with improved glycemic control.

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

AIM

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

METHOD

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

RESULTS

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

CONCLUSION

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

Diabetic kidney disease: impact of puberty

Puberty accelerates microvascular complications of diabetes mellitus, including nephropathy. Animal studies confirm a different renal hypertrophic response to diabetes before and after puberty, probably due to differences in the production of transforming growth factor-beta (TGF-beta). Many of the complex physiological changes during puberty could affect potentially pathogenic mechanisms of diabetic kidney disease. Increased blood pressure, activation of the growth hormone-insulin-like growth factor I axis, and production of sex steroids could all play a role in pubertal susceptibility to diabetic renal hypertrophy and nephropathy. These factors may influence the effects of hyperglycemia and several systems that ultimately control TGF-beta production, including the renin-angiotensin system, cellular redox systems, the polyol pathway, and protein kinase C. These phenomena may also explain gender differences in kidney function and incidence of end-stage renal disease. Normal changes during puberty, when coupled with diabetes and superimposed on a genetically susceptible milieu, are capable of accelerating diabetic hypertrophy and microvascular lesions. A better understanding of these processes may lead to new treatments to prevent renal failure in diabetes mellitus.

Age at diagnosis, glycaemic control and the development of retinopathy in a population-based cohort of Type 1 diabetic subjects in Canterbury, New Zealand

The aim was to determine the relationship between age at diagnosis, glycaemic control and the development of retinopathy in a population-based cohort of Type 1 diabetic subjects. At 1 January 1984, there were 286 individuals with Type 1 diabetes (and age of onset<20 years) on the Canterbury, New Zealand population register who had at least 2 prospective HbA(1c) readings (from 1 January 1984). Of these, 107 already had retinopathy. Of the 179 subjects without retinopathy at baseline 63 developed retinopathy during follow-up. After controlling for duration of diabetes (in the whole group), age at diagnosis was found to be a significant predictor of HbA(1c) level (P=0.001), with higher (mean+/-SD) baseline HbA(1c) in the 10-14 age group (7.95+/-2.14%), compared with (7.62+/-1.77%) in the <10 year group and (7.39+/-2.57%) in the >14 year group. The major predictors of retinopathy (in those without retinopathy at baseline), however were duration of diabetes (mean time to development of retinopathy decreases by 14% (95% CI 10-17%) for each year), baseline HbA(1c) (for each unit increase, mean time to development of retinopathy decreased by 23% (95%CI 13-32%) and HbA(1c) slope (average annual change). Peri-pubertal age at diagnosis (10-14 years) did not influence the time to onset of retinopathy over and above that attributed to duration of diabetes and glycaemic control.

A 6-year nationwide cohort study of glycaemic control in young people with type 1 diabetes. Risk markers for the development of retinopathy, nephropathy and neuropathy. Danish Study Group of Diabetes in Childhood

The study aimed to identify risk markers (present at the start of the study in 1989) for the occurrence and progression of microvascular complications 6 years later (in 1995) in a Danish nationwide cohort of children and adolescents with Type 1 diabetes (average age at entry 13.7 years). Probabilities for the development of elevated albumin excretion rate (AER), retinopathy, and increased vibration perception threshold (VPT) could then be estimated from a stepwise logistic regression model. A total of 339 patients (47% of the original cohort) were studied. Sex, age, diabetes duration, insulin regimen and dose, height, weight, HbA(1c), blood pressure, and AER were recorded. In addition, information on retinopathy, neuropathy (VPT), and anti-hypertensive treatment was obtained at the end of the study. HbA(1c) (normal range 4.3-5.8, mean 5.3%) and AER (upper normal limit <20 microg min(-1)) in two, timed overnight urine collections were analysed centrally. Eye examination was performed by two-field fundus photography. Determination of VPT was assessed by biothesiometry. Increased AER (> or =20 microg min(-1)) was found in 12.8% of the patients in 1995, and risk markers for this were increased AER and high HbA(1c), in 1989 (both p<0.001). Retinopathy was present in 57.8% of patients in 1995, for which the risk markers were long duration of diabetes (p<0.0001), age (p<0.01), and high HbA(1c) (p<0.0001) in 1989. Elevated VPT (>6.5 V) was found in 62.5% of patients in 1995, for which the risk markers were male sex (p<0.05), age (p<0.0001), and increased AER (p<0.05) in 1989. This study confirms that hyperglycaemia plays a major role for the development of microvascular complications in kidneys and eyes, and emphasises the need for optimal glycaemic control in children and adolescents with Type 1 diabetes.

Risk factors for diabetic retinopathy among Saudi diabetics

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

Aqueous flare intensity in relation to different stages of diabetic retinopathy

PURPOSE

To compare laser flare intensity in patients with diabetes mellitus (DM) type I and type II to different stages of diabetic retinopathy (DR) and controls.

METHODS

This study comprised 88 consecutive patients with DM type I and 40 controls in the same age range, divided into two age groups: 20-34 years and 35-50 years; 108 consecutive patients with DM type II and 32 controls were also divided into two age groups: 45-59 years and 60-75 years. Patients with glaucoma, exfoliation syndrome, media opacities, uveitis, within 96 hours after laser photocoagulation, treatment with topical and systemic drugs which can affect aqueous protein concentration, were excluded. One eye was randomly selected from each diabetic patient and control. Flare intensity was measured with a laser flare meter without mydriatic drops, and was then correlated with the stages of DR within each age group.

RESULTS

Eyes with advanced DR, such as moderate-severe, severe non-proliferative DR and proliferative DR (PDR), had significantly higher flare intensity than controls and eyes without retinopathy in all age groups (p<0.05). Flare intensity values were similar for controls and eyes with mild-moderate DR in all age groups except the older patients with DM type II, particularly those with clinically significant macular edema (CSME) (p<0.05). Eyes with regressed proliferative DR and no indication for laser photocoagulation had significantly lower flare values than eyes with an indication for therapy (p<0.05). Eyes with iris rubeosis (IR) had significantly higher flare than those without IR (p<0.05). Flare values were significantly correlated with the duration of diabetes in DM types I and II (p<0.05).

CONCLUSIONS

Flare intensity was increased in eyes with mild-moderate DR with CSME, and in eyes with advanced and severe stages of DR. Aqueous flare was related to the duration of diabetes.

Monitoring for retinopathy in children and adolescents with type 1 diabetes

In children with an average diabetes onset at 11 y of age, the first retinal changes can be expected after a median diabetes duration of 9 y, while the median time until clinically relevant background retinopathy is 14 y. Periodic examinations of the retinal status become necessary with the onset of puberty or after 5 y of diabetes duration. Only sensitive methods should be used for retinopathy screening; the minimum recommended standard is a stereoscopic slit-lamp biomicroscopic examination in mydriasis. The degree of glycaemic control, both before and after puberty, appears to be of outstanding importance for the development of retinopathy, but the contribution of other factors (arterial blood pressure, lipid abnormalities, sex steroids, smoking and genetic factors) may be of varying relevance in the individual patient. Thus, to improve the long-term prognosis for children with diabetes appropriate screening for retinopathy and associated risk factors is mandatory.

New developments in treating children with insulin-dependent diabetes mellitus

A number of new developments in the management of insulin-dependent diabetes mellitus have occurred in the past several years. Primary care providers including pediatric nurse practitioners need to be aware of these developments so that they can work effectively with specialty providers in caring for children with insulin-dependent diabetes mellitus. This article discusses the implications of the Diabetes Control and Complications Trial for children and adolescents, the Diabetes Prevention Trial-Type I, and several other recent developments in caring for children with insulin-dependent diabetes mellitus.

Epidemiology of late diabetic complications. A basis for the development and evaluation of preventive programs

This article examines the relationship between duration and level of glycemia in patients with diabetes and the occurrence of complications in the eyes, kidneys, and heart. Emphasis is placed on those aspects that are relevant to the development and evaluation of preventive and therapeutic programs against these complications. Data on patients with insulin-dependent diabetes mellitus are reviewed, and the similarities and differences with the data on patients with non-insulin-dependent diabetes mellitus are discussed.

The scotopic electroretinogram to blue flashes and pattern reversal visual evoked potentials in insulin dependent diabetes

Pattern reversal visual evoked responses (PR-VEPs), the electroretinogram (ERG) to blue flashes of light in dark adaptation, the steady state ERG to 40 Hz flicker, and alterations in pupil diameter following dark adaptation were studied in 56 juvenile onset diabetics, 34 of whom had no ophthalmoscopic or photographic evidence of diabetic retinopathy (DR-group). The remaining 22 had mild background retinopathy (DR+group). Normal data was obtained from 24 subjects matched for age and sex with diabetics. Skin electrodes were used for all recordings. The scotopic 'b' wave of the ERG was significantly lower in amplitude in the DR- diabetics and it was even more reduced in the DR+group. The PR-VEP was significantly delayed in diabetics but there was no difference between the two groups. The steady state ERG was not significantly different between normals and diabetics. These findings indicate that retinal and more central abnormalities develop early in diabetics. Detection of objective electrophysiological abnormalities may be used to identify persons at risk of developing retinopathy and to monitor the effects of treatment.

Development and progression of diabetic retinopathy: adolescents at risk

The aims of this study were to evaluate short-term changes in retinopathy in adolescents, and to examine the relationship of these changes to risk factors. Two-hundred and three adolescents, with a median age of 14.5 (range 10.4 to 20.6) yr and a median duration of diabetes of 6.6 (1.1 to 16.3) yr, were included in the study. Retinopathy was assessed on two occasions, using stereoscopic fundus photography; the median time between assessment was 1.3 (0.5 to 3.0) yr. At baseline, 41% of the adolescents had background retinopathy. When patients were stratified according to the median diabetes duration (DD) (6.6 yr) and glycaemic control over the 12 months prior to assessment (HbA1C) (8.4%), the percentage of retinopathy in each group was: lowDD/lowHbA1C 13%; lowDD/highHbA1C 40%; highDD/lowHbA1C 42%; and highDD/highHbA1C 72%. Using a 2-step criteria for stability or change in retinopathy, 11% of the 203 adolescents showed progression of retinopathy, 41% had stable retinopathy, 5% showed regression, and 43% had no retinopathy at either assessment. Change in retinopathy was related to age at baseline assessment (borderline significance, p = 0.06), diabetes duration (p < 0.001), glycaemic control (p < 0.001) and total cholesterol (p = 0.04), and was also related to DD/HbA1C group membership (chi 2, p < 0.001). This study highlights the combined adverse effect of long diabetes duration and poor glycaemic control on the development and progression of retinopathy during adolescence, and identifies a group that is likely to show progression over a relatively short period.

Good blood glucose control characterizes patients without retinopathy after long diabetes duration

The importance of blood glucose control for the avoidance of retinopathy was assessed by monitoring glycated haemoglobin for 5 years or more in Type 1 (insulin-dependent) diabetic patients diagnosed before an age of 31 years, and with a diabetes duration of 20 years or more. They were followed up for an average of 9.4 years with 3.3 measurements per year. Of the 213 included patients, 16 had no retinopathy, 126 had background retinopathy (including 8 with macula oedema) and 71 had proliferative retinopathy. patients without retinopathy had a mean HbA1c +/- SEM for the whole follow-up period of 6.3 +/- 0.19%, the 117 patients with background retinopathy but not macula oedema 7.0 +/- 0.08%; Mann-Whitney test vs group without retinopathy p = 0.003, macula oedema 7.9 +/- 0.31%; p = 0.001, and proliferative retinopathy 7.4 +/- 0.09; p < 0.001. The mean duration was 31 years, without significant differences between the groups. In conclusion, these results suggests that good blood glucose control is of major importance to prevent or postpone diabetic retinopathy also after long duration of diabetes, and that no patient with high HbA1c levels for several years is protected from retinopathic lesions.

Prevalence and risk factors for retinopathy in adolescents with type 1 diabetes

OBJECTIVES

To establish the prevalence of, and risk factors associated with, diabetic retinopathy in an Australian adolescent diabetes clinic population.

DESIGN

A prospective longitudinal study; baseline findings.

PATIENTS

Two hundred and fifty-five patients with Type 1 (insulin-dependent) diabetes mellitus assessed by our service were studied. Entry criteria were: age 11.0-19.9 years; diabetes duration of at least two years; and gradable fundus photographs of at least one eye.

MAIN OUTCOME MEASURES

The presence and severity of retinopathy, as assessed by the grading of stereoscopic fundus photographs. Possible risk factors assessed were age, sex, diabetes duration, pubertal stage, blood pressure, glycaemic control and total cholesterol level.

RESULTS

The prevalence of retinopathy was 42%; all of those affected had mild background retinopathy. Highly significant associations were found with glycaemic control and both total and prepubertal duration of diabetes. No associations were found with age, sex, pubertal stage, blood pressure or total cholesterol level.

CONCLUSIONS

The high prevalence of early diabetic retinopathy in this group of Australian adolescents is comparable to recent reports from other centres. The significant associations with glycaemic control and duration of diabetes provide further strong evidence for the benefit of optimal glycaemic control during adolescence. Our finding that the prepubertal years of diabetes contribute to the development of retinopathy suggests that glycaemic control before puberty should also be optimised. The planned follow-up of this cohort will establish the risk of progression to vision-threatening retinopathy and allow risk factors to be further evaluated.