Prevalence and correlations of early microvascular complications in young type I diabetic patients: role of puberty

HbA1c levels in children with type 1 diabetes and correlation to diabetic retinopathy

BACKGROUND

Type 1 diabetes mellitus (T1D) is a metabolic disease causing hyperglycemia due to β-cell destruction. Despite adequate treatment, complications such as diabetic retinopathy (DR) are common. The first aim was to investigate if acute onset of type 1 diabetes differed between those who had developed retinopathy and who had not after 15 years from diagnosis. The second aim was to investigate if mean glycosylated hemoglobin (HbA1c) levels affect the time to development of DR.

METHODS

The medical records of all children and adolescents diagnosed with type 1 diabetes during 1993-2001 in our area in Sweden were studied retrospectively and the mean HbA1c each year until the development of retinopathy was investigated. In total 72 patients were included and the follow-up time was between 15 and 23 years. Gender, p-glucose, age and HbA1c at diagnosis were analyzed for possible correlations to years to retinopathy.

RESULTS

HbA1c was significantly higher among those who had developed DR after 15 years from diagnosis, 98±9.2 (n=25) vs. 86±9.2 (n=46; p=0.025). A negative correlation was found between age at diagnosis and years to DR (rs=-0.376; p=0.026). Mean HbA1c levels at years 6-10 after diabetes diagnosis correlated significantly (rs=-0.354, p=0.037) to years until retinopathy. Mean HbA1c levels at years 1-15 after diabetes diagnosis were significantly higher at years 2-3 and years 5-8 for those who had developed retinopathy after 15 years from diagnosis.

CONCLUSIONS

Higher HbA1c levels shortened the time to development of retinopathy. It is therefore important to keep HbA1c as close to normal as possible.

Long-term Outcomes in Youths with Diabetes Mellitus

In this article, the author reviews the long-term outcomes and their precursors of type 1 diabetes starting in youth. The author also contrasts the changing incidence of these long-term complications as we have moved from the pre-Diabetes Control and Complications Trial (DCCT) to the post-DCCT standard of care and reviews the emerging data related to complications in youths with type 2 diabetes. Finally, the author reviews the recent understanding related to the effects of diabetes on the brain and cognition.

A comparison of multiple daily insulin therapy with continuous subcutaneous insulin infusion therapy in adolescents with type 1 diabetes mellitus: a single-center experience from Turkey

AIM

To compare the long-term outcomes of continuous subcutaneous insulin infusion (CSII) pump therapy with the clinical and metabolic parameters recorded during multiple daily insulin (MDI) therapy.

PATIENTS AND METHODS

CSII pump was used by volunteer adolescents, who had a duration of diabetes mellitus (DM) longer than one year, regularly attended periodic examinations for the last year, measured and recorded blood glucose levels on average 3 to 4 times a day, and did not achieve the preferred metabolic control even though the use of MDI therapy. Carbohydrate counting and flexible MDI therapy was taught to these patients before CSII pump implantation. The metabolic and clinical parameters of the patients for the post-CSII pump period were compared with the data of flexible and non-flexible MDI periods.

RESULTS

The mean CSII pump implantation age of the 17 adolescents enrolled in the study was 15.53 +/- 1.8 years, duration of DM 6.77 +/- 4.05 years, flexible MDI injection duration 0.70 +/- 0.20 years, and duration of CSII pump use 2.07 +/- 1.12 years. A decrease was detected in HbA(1c) levels of the patients with transition to CSII pump compared to flexible and non-flexible MDI injection periods; however, this decrease was not statistically significant (7.71%, 8.21%, and 8.71%, respectively, p = 0.105). No statistically significant difference was detected in frequency of hypoglycemia, lipid profiles, total daily insulin requirement, and BMI SDS values of the patients when data of the post-CSII pump state were compared with that of flexible and non-flexible MDI therapy groups.

CONCLUSION

In adolescents, it was found that CSII pump therapy is efficient and safe without any increased risk for weight gain and hypoglycemia compared to flexible and non-flexible MDI injection periods. The present study also demonstrated that flexible MDI injection therapy might be efficiently and safely used in patients who cannot receive CSII pump therapy due to social and/or financial factors.

Prevalence and risk factors for microalbuminuria in a population-based sample of children and adolescents with T1DM in Western Australia

OBJECTIVE

To define the prevalence and describe the natural history of microalbuminuria (MA) in a population-based sample of children with type 1 diabetes mellitus (T1DM).

METHODS

Children with T1DM diagnosed <or=16 yrs and screened for MA were identified through the Western Australia diabetes register. Three-monthly hemoglobin (HbA1c) was performed from diagnosis. MA screening (albumin excretion rate in three timed overnight samples) was performed yearly after 10 yrs of age or after 5 yrs from diagnosis. Cox proportional model assessed the risk of different variables on the occurrence of MA. Kaplan-Meier survival analyses (log-rank test) estimated the probability of developing MA.

RESULTS

Nine hundred and fifty-five T1DM children (462 male), mean diabetes duration of 7.6 yrs and mean age at onset of diabetes of 8.5 yrs were selected for the study. MA, mean albumin excretion rate >or=20 and <200 microg/min, developed in 128 subjects (13.4%) at mean diabetes duration of 7.6 yrs. Cumulative probability for MA was 16% after 10 yrs. Determinants for MA were HbA1c [hazard ratio (HR) 1.21; 95% confidence interval (CI) 1.05-1.38; p = 0.007], onset of puberty (HR 8.01; 95% CI 3.18-20.16; p < 0.001) and age at diagnosis (HR 1.25; 95% CI 1.18-1.33; p < 0.001). Females had a higher probability for MA during puberty than males (p = 0.03). The total incidence of MA (subjects with MA/100 person-years) was 1.26, 1.85 and 2.44 for those who developed diabetes at ages <5 yrs, 5-11 yrs and >11 yrs, respectively.

CONCLUSIONS

Onset of puberty, diabetes duration and metabolic control are major factors predisposing the development of MA. Children diagnosed with T1DM at younger ages have a prolonged time for developing MA.

Early diabetic complications in a population of young patients with type 1 diabetes mellitus despite intensive treatment

AIM

To describe the prevalence of early complications in an unselected population of patients with type 1 diabetes mellitus (DM1) diagnosed in childhood with intensive insulin treatment from diagnosis.

METHODS

Eighty children and adolescents with DM1, age 7-22 years and DM1 duration >3 years, were studied. Neuropathy was defined as abnormal nerve conduction finding in > or = 2 of 4 nerves (sural and peroneal nerves), nephropathy as albumin excretion rate > or = 20 microg/min and retinopathy as all grades of retinal changes in fundus photographs.

RESULTS

The prevalence of neuropathy was 59%, of retinopathy 27% and of nephropathy 5% after 13 years DM1 duration. Mean (SD) long-term HbA1c was 8.4 (0.9)% (DCCT-corrected value).

CONCLUSION

Even in a population with intensive insulin treatment from the beginning and fairly good metabolic control, the prevalence of subclinical neuropathy was high, while other diabetic complications were lower than usually reported.

Complications of diabetes mellitus in childhood

Complications of diabetes include retinopathy, nephropathy, neuropathy, macrovascular disease, and associated autoimmune diseases. Clinical manifestations of complications uncommonly present in childhood and adolescence. Screening during the early years can identify subclinical disease and it offers an opportunity for early intervention. The Diabetes and Complications Control Trial has provided evidence for the long-term benefits of good glycemic control in preventing and delaying the onset of microvascular complications. Complications begin to manifest during adolescence, during which time all efforts should be made to educate and support young persons in achieving optimal diabetes control.

Impact of hormone replacement therapy on microvascular function in healthy and Type 2 diabetic postmenopausal women

AIMS

Hormone replacement therapy (HRT) has been previously reported to modulate vascular function and cardiovascular risk. Its impact on the macrocirculation has previously been explored, however, little data is available on its impact on the microcirculation. This study aimed to determine the impact of HRT on microvascular function in healthy and Type 2 diabetic postmenopausal women (n=20 and 17, respectively).

METHODS

Microvascular function was assessed by skin maximum hyperaemia, skin hyperaemic response to iontophoretically applied acetylcholine (endothelial-dependent vasodilator) and sodium nitroprusside (endothelial-independent vasodilator), capillary pressure and the microvascular filtration capacity. Microvascular assessments were carried out at baseline and repeated following 6 months' oral hormone replacement therapy (1 mg oestradiol/0.5 mg norethisterone or 1 mg unopposed oestradiol for hysterectomized women).

RESULTS

Following 6 months' therapy there were no significant changes in microvascular assessments in the healthy women. In the diabetic women there was a reduction in the skin hyperaemic response to acetylcholine [median pretreatment peak response: 1.95 (25th, 75th centiles: 1.54, 2.30) V vs. post-treatment peak response: 1.53 (1.30, 1.91) V (P=0.011, Wilcoxon's signed rank test)] and sodium nitroprusside [median peak response 1.59 (1.37, 1.99) vs. 1.35 (0.92, 1.63) V (P=0.011)] with HRT, but no other changes.

CONCLUSION

These data suggests that HRT does not affect microvascular function in healthy women, but adversely affects it in diabetic women. These findings may help to explain why HRT fails to provide the predicted cardiovascular protection, and raises the possibility that HRT influences microangiopathy progression in diabetic women.

Epidemiology of diabetic retinopathy and macular oedema: a systematic review

AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Prevalence of microalbuminuria in young patients with type 1 and type 2 diabetes mellitus

This study was designed to determine the prevalence of microalbuminuria and the associated risk factors in patients with childhood-onset diabetes mellitus (DM). One hundred and sixty-three patients (141 with type 1 DM [DM1] and 22 with type 2 DM [DM21), aged 8 to 28 years, were evaluated for albumin excretion rate and HbA(1c). The mean duration of DM was 8.1 +/- 3.4 and 5.5 +/- 3.9 years in DM1 and DM2, respectively. Persistent microalbuminuria and macroalbuminuria were observed in 11.3% and 2.8% of patients with DM1, and 18.2% and 4.5% in patients with DM2, respectively. In DM1, the duration of DM, age of onset, and HbA(1c) levels were significant predictors of microalbuminuria. Our observations suggest that screening for microalbuminuria should be started from early adolescence in patients with DM1 and DM2.

Evaluation of sensorimotor polyneuropathy in children and adolescents with type I diabetes: associations with microalbuminuria and retinopathy

To investigate diabetic polyneuropathy, we measured peroneal motor conduction velocity, sural sensory nerve conduction velocity and vibratory sense threshold (biothesiometry) in 28 children and adolescents with insulin-dependent diabetes (type 1), and in 28 age- and sex-matched, normal controls. Age varied from 8 to 19 yr (mean +/- SD = 13.04 +/- 2.61); age at the onset of diabetes from 9 months to 12 yr (4.53 +/- 2.42 yr); and the duration of diabetes from 5 to 16 yr (8.48 +/- 2.98). Eight patients (28%) fulfilled the minimal criteria for the diagnosis of polyneuropathy. Four of these patients showed symptoms while three had clinical signs of neuropathy. Eight patients had abnormal, sural sensory nerve conduction velocities. The presence of polyneuropathy did not correlate with the duration of diabetes or degree of metabolic control of diabetes. The prevalence of microvascular complications (microalbuminuria and retinopathy) was 32%. The presence of microvascular complications did not correlate with metabolic control but did with the duration of diabetes. The relationship between polyneuropathy and microvascular complications was 34%.

The early natural history of nephropathy in type 1 diabetes: I. Study design and baseline characteristics of the study participants

This report describes the design and baseline demographic and clinical data in the study of the early natural history of diabetic nephropathy (DN) in type 1 diabetes carried out by the International Diabetic Nephropathy Study Group. The study enrolled 243 patients ages 10-40 years (16.8 +/- 6.0, mean +/- SD) with type 1 diabetes for 2-20 years (8.0 +/- 4.2) at centers in the United States (Minneapolis), Canada (Montreal), and France (Paris). At baseline, all patients were normotensive, none had reduced glomerular filtration rate (GFR), and all but eight were normoalbuminuric (NA). All patients had baseline renal biopsies. During the study, patients will have multiple measurements of blood pressure (BP), renal function, albumin excretion rate (AER), glycemia, and other variables, with repeat renal biopsies planned at 5 years after baseline. The 31.3% of the approached patients who agreed to participate were similar in age, diabetes duration, HbA(1c), AER, and sex to those refusing participation. Age, diabetes duration, HbA(1c), and AER were similar among the three centers, but systolic BP, GFR, renal plasma flow (RPF), and filtration fraction were lower in the Paris center. The 153 patients with hyperfiltration (GFR >130 ml x min(-1) x 1.73 m(-2)) had greater RPF than those with normal GFR. The eight microalbuminuric patients tended to have longer duration of diabetes but were otherwise similar to the NA patients. The role of these and other variables in determining the development rate of the early lesions of DN over the 5 years between biopsies is the central issue under study.

Retinopathy in juvenile diabetes: a 10-year (1990-2000) review

Diabetic retinopathy (DR) is the most frequent complication of diabetes and a leading cause of impaired vision in the Western world. There is general agreement that early diagnosis and treatment of DR can slow its progression and help to prevent blindness. However, as a result of its asymptomatic nature and its etiopathogenesis, which is still unclear due to its multifactorial complexity, DR-related blindness has a growing social impact in industrialized countries. Therefore, in order to gain a better understanding of this serious disease, the author performed an updated 10-year review of risk factors and management of DR in type 1 diabetes.

Early diabetes-related complications in children and adolescents with type 1 diabetes. Implications for screening and intervention

Although children and adolescents with type 1 diabetes are faced with the threat of the acute complications of hypoglycemia and ketoacidosis on a day-to-day basis, in the long-term, the microvascular and macrovascular complications of the disease place them at greatest risk for serious morbidity and earlier than expected mortality. The families of children with diabetes should be provided with information about the complications of diabetes beginning at the time of diagnosis, and this information needs to be reinforced throughout the follow-up period. Appropriate surveillance for the earliest evidence of microvascular disease should begin at the onset of puberty and after 3 to 5 years of diabetes. Therapeutic interventions, particularly excellent metabolic control, may be exceedingly effective in preventing complication onset or significantly retarding the rate of progression.