Relationship between early metabolic control and the development of microalbuminuria--a longitudinal study in children with type 1 (insulin-dependent) diabetes mellitus

Diabetes Study of Children of Diverse Ethnicity and Race: Study design

AIMS

Determining diabetes type in children has become increasingly difficult due to an overlap in typical characteristics between type 1 diabetes (T1D) and type 2 diabetes (T2D). The Diabetes Study in Children of Diverse Ethnicity and Race (DISCOVER) programme is a National Institutes of Health (NIH)-supported multicenter, prospective, observational study that enrols children and adolescents with non-secondary diabetes. The primary aim of the study was to develop improved models to differentiate between T1D and T2D in diverse youth.

MATERIALS AND METHODS

The proposed models will evaluate the utility of three existing T1D genetic risk scores in combination with data on islet autoantibodies and other parameters typically available at the time of diabetes onset. Low non-fasting serum C-peptide (<0.6 nmol/L) between 3 and 10 years after diabetes diagnosis will be considered a biomarker for T1D as it reflects the loss of insulin secretion ability. Participating centres are enrolling youth (<19 years old) either with established diabetes (duration 3-10 years) for a cross-sectional evaluation or with recent onset diabetes (duration 3 weeks-15 months) for the longitudinal observation with annual visits for 3 years. Cross-sectional data will be used to develop models. Longitudinal data will be used to externally validate the best-fitting model.

RESULTS

The results are expected to improve the ability to classify diabetes type in a large and growing subset of children who have an unclear form of diabetes at diagnosis.

CONCLUSIONS

Accurate and timely classification of diabetes type will help establish the correct clinical management early in the course of the disease.

Challenges in the diagnosis of diabetes type in pediatrics

The incidence of diabetes, both type 1 and type 2, is increasing. Health outcomes in pediatric diabetes are currently poor, with trends indicating that they are worsening. Minority racial/ethnic groups are disproportionately affected by suboptimal glucose control and have a higher risk of acute and chronic complications of diabetes. Correct clinical management starts with timely and accurate classification of diabetes, but in children this is becoming increasingly challenging due to high prevalence of obesity and shifting demographic composition. The growing obesity epidemic complicates classification by obesity's effects on diabetes. Since the prevalence and clinical characteristics of diabetes vary among racial/ethnic groups, migration between countries leads to changes in the distribution of diabetes types in a certain geographical area, challenging the clinician's ability to classify diabetes. These challenges must be addressed to correctly classify diabetes and establish an appropriate treatment strategy early in the course of disease for all. This may be the first step in improving diabetes outcomes across racial/ethnic groups. This review will discuss the pitfalls in the current diabetes classification scheme that is leading to increasing overlap between diabetes types and heterogeneity within each type. It will also present proposed alternative classification schemes and approaches to understanding diabetes type that may improve the timely and accurate classification of pediatric diabetes type.

Future glycemic control of children diagnosed with type 1 diabetes mellitus at toddler and preschool/school age

Background The main objective of this study was to compare future glycemic control in children diagnosed with type 1 diabetes mellitus (T1DM) at toddler age and preschool/school age. In addition, we aimed to examine risk factors known to be associated with future glycated hemoglobin A1c (HbA1c) levels in children diagnosed with T1DM. Methods This is a retrospective cohort study of 85 patients diagnosed with T1DM at toddler age (group 1; 0-2.9 years; n = 36) or preschool/school age (group 2; 5-6.9 years; n = 49) who were followed up at the University Children's Hospital in Zurich for at least 10 consecutive years or until the age of 15 years. Results The mean HbA1c level in the first year after diagnosis had a highly predictive value about glycemic control in the following 6 years. In addition, a longer duration of T1DM was associated with higher HbA1c values. HbA1c values did not differ significantly within 11 years after diagnosis between children in the two age groups. Neither was a difference found when comparing the two groups in respect to their chronological age, although a trend was noted (p = 0.09). This trend is very likely due to a longer duration of diabetes in group 1. Conclusions HbA1c level in the first year predicts glycemic control for the next 6 years and deterioration of HbA1c values can be noted with longer duration of T1DM. Moreover, our study demonstrated similar future glycemic control in patients diagnosed with T1DM at toddler age and preschool/school age.

Diabetic ketoacidosis at diagnosis of type 1 diabetes and glycemic control over time: The SEARCH for diabetes in youth study

BACKGROUND

The diagnosis of type 1 diabetes (T1D) in youth is often associated with diabetic ketoacidosis (DKA). We aimed to evaluate if the presence of DKA at diagnosis of T1D is associated with less favorable hemoglobin A1c (HbA1c) trajectories over time.

METHODS

The SEARCH for Diabetes in Youth study of 1396 youth aged <20 years with newly diagnosed T1D were followed for up to 13 (median 8 [interquartile range or IQR 6-9]) years after diagnosis. Of these, 397 (28%) had DKA (bicarbonate level < 15 mmol/L and/or pH < 7.25 (venous) or < 7.30 (arterial or capillary) or mention of DKA in medical records) at diabetes onset. Longitudinal HbA1c levels were measured at each follow-up visit (average number of HbA1c measures 3.4). A linear piecewise mixed effects model was used to analyze the effect of DKA status at diagnosis of T1D on long-term glycemic control, adjusting for age at diagnosis, diabetes duration at baseline, sex, race/ethnicity, household income, health insurance status, time-varying insulin regimen and glucose self-monitoring, study site, and baseline fasting C-peptide level.

RESULTS

At baseline, HbA1c levels were significantly higher in youth with T1D diagnosed in DKA vs those who were not (9.9% ± 1.5% vs 8.5% ± 1.4%, respectively). After the first year with diabetes, there was a significant difference in the rate of change in HbA1c levels by DKA status: HbA1c was 0.16% higher each year in youth with DKA compared to those without (interaction P-value<0.0001), after adjusting for aforementioned covariates.

CONCLUSIONS

DKA at T1D diagnosis is associated with worsening glycemic control over time, independent of demographic, socioeconomic, and treatment-related factors and baseline fasting C-peptide.

Risk Factors Associated with Microalbuminuria in Children and Adolescents with Diabetes in Bangladesh

INTRODUCTION

Diabetic nephropathy is leading cause of morbidity and mortality of type 1 diabetes mellitus (DM). Microalbuminuria is the first clinical sign of nephropathy.

METHODS

This was a cross-section study with longitudinal evaluation of urinary albumin xcretion in 199 children with type 1 diabetes attending CDiC Clinic in BIRDEM over a period of two years. The aim of the study was to assess the frequency of microalbuminuria and to determine other risk factors. We collected blood and early morning spot urinary sample and analyzed for HbA1c by Clover A1c and urinary microalbumin by a DCA analyzer. Children had urinary microalbumin 30-300 mg/L on at least two occasions were categorized as having persistent microalbuminuria. Demographic and clinical data were recorded including age at onset of diabetes, age during registration, gender and duration of diabetes which were compared between patients without microalbuminuria and with microalbuminuria.

RESULT

Microalbuminuria developed in forty nine children and adolescents (25%). Among them 24% were Type 1, 27% were with Fibrocalculous pancreatic diabetes (FCPD) and 68% were Type 2 diabetes. Median HbA1c was higher 10.8 [9.4-12.4] vs 9.5 [8.0-11.2] (P.006) in adolescents with microalbuminuria. On logistic regression univariate analysis independent predictors of microalbuminuria were older age, systolic blood pressure, BMI SDS and mean HbA1c which remained significant in multivariate analysis as predictors of microalbuminuria.

CONCLUSION

We found high prevalence of microalbuminuria which was associated with higher age, systolic blood pressure, BMI SDS and HbA1c.

Diabetic Ketoacidosis at Diagnosis of Type 1 Diabetes Predicts Poor Long-term Glycemic Control

OBJECTIVE

This study tested the hypothesis that diabetic ketoacidosis (DKA) at diagnosis of type 1 diabetes in children predicts poor long-term glycemic control independently of established risk factors.

RESEARCH DESIGN AND METHODS

This was a prospective cohort study of 3,364 Colorado residents diagnosed with type 1 diabetes before 18 years of age, in 1998-2012, and monitored for up to 15 years. Of those, 1,297 (39%) had DKA at diagnosis (blood glucose >250 mg/dL, and venous pH <7.3 or bicarbonate <15 mEq/L). Severity of DKA was further classified as mild/moderate (pH 7.10-7.29 or bicarbonate 5-14 mEq/L) or severe (pH <7.10 or bicarbonate <5 mEq/L). HbA_1c levels were measured an average of 2.8 times/year (median 20 HbA_1c values/patient). A linear mixed model was used to examine the effect of DKA on long-term HbA_1c levels, adjusting for age, race/ethnicity, sex, family history of diabetes, health insurance, and insulin pump use.

RESULTS

DKA at diagnosis predicted persistently elevated HbA_1c levels. Compared with children without DKA, HbA_1c tracked 1.4% (15.3 mmol/mol) higher in those with severe DKA (P < 0.0001) and 0.9% (9.8 mmol/mol) higher in those with mild/moderate DKA at diagnosis (P < 0.0001). These effects were independent of ethnic minority status or lack of health insurance at diagnosis that predicted higher HbA_1c by 0.5% (5.5 mmol/mol; P < 0.0001) and 0.2% (2.2 mmol/mol; P < 0.0001), respectively. Insulin pump use or having a parent or sibling with type 1 diabetes predicted lower long-term HbA_1c by, respectively, 0.4% (4.4 mmol/mol; P < 0.0001) and 0.2% (2.2 mmol/mol; P = 0.01).

CONCLUSIONS

DKA at diagnosis of type 1 diabetes in children predicts poor long-term glycemic control, independent of demographic and socioeconomic factors.

Age at menarche and the risk of diabetic microvascular complications in patients with type 1 diabetes

AIMS/HYPOTHESIS

The aim of this study was to evaluate the relationship among age at onset of diabetes, age at onset of menarche and risk of diabetic nephropathy and laser-treated retinopathy in type 1 diabetes.

METHODS

Data related to age at menarche were collected through questionnaires and were available for 1,304 women who participated in the Finnish Diabetic Nephropathy Study (FinnDiane). A possible association between age at menarche and diabetic nephropathy and retinopathy was investigated.

RESULTS

There was an inverse relationship between the age at onset of diabetes and age at menarche: the younger the age at onset of diabetes, the higher the age at menarche (p < 0.0001). A non-linear relationship between the age of menarche and risk of diabetic microvascular complications was found in patients with diabetes onset before menarche, but there was no such association in patients with diabetes onset after menarche. Women with delayed menarche (> mean age + 2 years) had a 2.30 (95% CI 1.27, 4.17; p < 0.006) times higher risk of nephropathy compared with the women who underwent menarche at the mean age ± 2 years. Delayed menarche also increased the risk of retinopathy (OR 2.34 [95% CI 1.36, 4.01]). After excluding patients with nephropathy, the OR for retinopathy was 2.11 (95% CI 1.15, 3.90). Earlier menarche (< mean age - 2 years) did not have any effect on this risk.

CONCLUSIONS/INTERPRETATION

Delayed menarche was associated with an increased risk of diabetic nephropathy and retinopathy, whereas early menarche was not. Delayed menarche may be used as a new tool to identify women at risk of diabetic microvascular complications.

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.

Pediatric Diabetes Consortium Type 1 Diabetes New Onset (NeOn) Study: factors associated with HbA1c levels one year after diagnosis

OBJECTIVE

To identify determinants of hemoglobin A1c (HbA1c) levels 1 yr after the diagnosis of type 1 diabetes (T1D) in participants in the Pediatric Diabetes Consortium (PDC) T1D New Onset (NeOn) Study.

RESEARCH DESIGN AND METHODS

Diabetes-specific as well as socioeconomic factors during the first year following diagnosis were analyzed in 857 participants (mean age 9.1 yrs, 51% female, 66% non-Hispanic White) not participating in an intervention study who had an HbA1c value at 12 months.

RESULT

Mean ± SD HbA1c at 1 yr was 62 ± 16 mmol/mol (7.8% ± 1.5). In univariate and multivariate analyses, clinical center, non-Hispanic White race, private health insurance, living with both parents, higher frequency of self-monitoring of blood glucose (SMBG), and lower insulin requirements were associated with lower HbA1c concentrations at 1 yr (p < 0.01). No association was found with gender, age, Tanner stage, body mass index (BMI), diabetic ketoacidosis (DKA) at onset, number of positive autoantibodies or HbA1c at onset, or number of visits to diabetes physician during the first year.

CONCLUSIONS

White race, higher socioeconomic status, two-parent household, more frequent SMBG, and low insulin requirements are associated with lower HbA1c concentration 1 yr after the onset of T1D in children.

Gastric emptying of solids and its relationship with microalbuminuria in children and adolescents with type 1 diabetes mellitus

BACKGROUND

The aims of the present study were to determine the frequency of delayed gastric emptying in children and adolescents with type 1 diabetes mellitus (T1DM) and to investigate the relationship between gastric emptying rate and other contributing factors (e.g. serum HbA1c, duration of diabetes and microalbuminuria) in these patients.

METHODS

This was a clinical trial evaluating the rate of gastric emptying of solid meals in 33 children and adolescents with T1DM and in 26 healthy peers using a radionuclide method. Three consecutive overnight urine collections were used to calculate the albumin excretion rate.

RESULTS

There was no significant difference in the gastric half-emptying time (GE t½ ) between patients and controls (151.7 ± 154.5 vs 109.8 ± 60.5 min, respectively; P=0.885) or the frequency of delayed gastric emptying (36.4% vs 30.8%, respectively; P=0.433). There was a moderately positive correlation between GE t½ and the duration of diabetes (r=0.380; P=0.029). There was no correlation between GE t½ and microalbumin levels in T1DM patients. In these patients, the body mass index standard deviation scores were significantly lower than in patients with normal gastric emptying (-0.13 ± 0.87 vs 0.7 ± 1.23, respectively; P=0.044).

CONCLUSION

Progression of delayed gastric emptying is more likely to be related to a longer duration of diabetes than glycemic control in children and adolescents with T1DM. Patients with delayed gastric emptying are thinner compared with patients with a normal rate of gastric emptying; they may also be asymptomatic.

Sex-related differences in the long-term risk of microvascular complications by age at onset of type 1 diabetes

AIMS/HYPOTHESIS

This study examined sex-related differences in the cumulative risk of proliferative retinopathy (PR) and end-stage renal disease (ESRD) over 40 years of duration of type 1 diabetes according to age at diabetes onset.

METHODS

We assessed 4,416 patients from the Finnish Diabetic Nephropathy Study population. Kaplan-Meier analysis was used to provide cumulative incidence rates and Cox regression analyses for HRs.

RESULTS

There were no sex-related differences in the cumulative incidence of ESRD in patients diagnosed with type 1 diabetes between 0 to 4 and 5 to 9 years. Thereafter the risk started to diverge. The cumulative incidence of ESRD in patients diagnosed between 10 to 14 and ≥15 years was 17.4% (95% CI 13.4-21.2) and 13.0% (9.6-16.2) respectively in women, while in men it was 32.2% (28.0-36.1) and 24.6% (20.8-28.1) respectively. The respective HRs were (onset at 10 to 14 years) 1.9 (p < 0.0001) and (onset at ≥15 years) 1.8 (p < 0.001), respectively. There was no difference in the risk of PR between men and women diagnosed between 0 and 4 years of age, but progressive sex-related differences in the cumulative incidence of PR were observed with increasing age at onset. The HRs for men in the age-at-onset groups 5 to 9, 10 to 14 and ≥15 years of age were 1.3 (95% CI 1.0-1.6), 1.3 (1.1-1.6) and 2.1 (1.6-2.6) compared with women in these groups, respectively.

CONCLUSIONS/INTERPRETATION

The difference between the sexes with regard to risk of diabetic microvascular complications is highly dependent on the age at onset of diabetes. The risk of ESRD and PR risk doubled in men compared with women when age at onset was ≥15 years.

Predictors of microvascular complications in type 1 diabetic patients at onset: the role of metabolic memory

BACKGROUND

Several epidemiological studies showed a close association between metabolic control and microvascular complications in type 1 Diabetes Mellitus (T1DM). The aim of our longitudinal observational study was to evaluate the predictive role of the main clinical and biochemical parameters in determining microvascular complications.

METHODS

376 T1DM patients, hospitalized in our division from 1991 to 2005 (mean follow-up=10.93±4.26 years) were studied. Stepwise Cox regression analysis was used to identify the influence of residual ß-cell function, ß-cell autoimmunity, HbA1c levels and other clinical and laboratory parameters in the development of microalbuminuria and retinopathy.

RESULTS

The probability of developing microalbuminuria was higher in males than in females (HR 1.82; 95% CI 1.01-3.28; p=0.044), in patients with higher mean HbA1c values (HR 2.80; 95% CI 1.63-4.83; p<0.001), longer duration of disease (HR 1.98; 95% CI 1.10-3.57; p=0.022) and younger age of diabetes onset (HR 0.53; 95% CI 0.03-0.92; p=0.026). An increased probability of developing retinopathy was found in patients with higher mean HbA1c levels during follow-up (HR 2.35; 95% CI 1.34-4.12, p=0.003), as well as at onset (HR 1.85; 95% CI 1.06-3.24; p=0.030).

CONCLUSIONS

Our study suggests that among the clinical, metabolic, immunological and biochemical factors evaluated at onset, only HbA1c is predictive for the microangiopathy development in T1DM.

Diabetic nephropathy in children and adolescents

Type 1 diabetes mellitus (T1DM) commonly occurs in childhood or adolescence, although the rising prevalence of type 2 diabetes mellitus (T2DM) in these age groups is now being seen worldwide. Diabetic nephropathy (DN) develops in 15-20% of subjects with T1DM and in similar or higher percentage of T2DM patients, causing increased morbidity and premature mortality. Although overt DN or kidney failure caused by either type of diabetes are very uncommon during childhood or adolescence, diabetic kidney disease in susceptible patients almost certainly begins soon after disease onset and may accelerate during adolescence, leading to microalbuminuria or incipient DN. Therefore, all diabetics warrant ongoing assessment of kidney function and screening for the earliest manifestations of renal injury. Pediatric health care professionals ought to understand about risk factors, strategy for prevention, method for screening, and treatment of early DN. This review considers each form of diabetes separately, including natural history, risk factors for development, screening for early manifestations, and strategy recommended for prevention and treatment of DN in children and adolescents.

Risk of microalbuminuria and progression to macroalbuminuria in a cohort with childhood onset type 1 diabetes: prospective observational study

OBJECTIVES

To describe independent predictors for the development of microalbuminuria and progression to macroalbuminuria in those with childhood onset type 1 diabetes.

DESIGN

Prospective observational study with follow-up for 9.8 (SD 3.8) years.

SETTING

Oxford regional prospective study.

PARTICIPANTS

527 participants with a diagnosis of type 1 diabetes at mean age 8.8 (SD 4.0) years.

MAIN OUTCOME MEASURES

Annual measurement of glycated haemoglobin (HbA1c) and assessment of urinary albumin:creatinine ratio.

RESULTS

Cumulative prevalence of microalbuminuria was 25.7% (95% confidence interval 21.3% to 30.1%) after 10 years of diabetes and 50.7% (40.5% to 60.9%) after 19 years of diabetes and 5182 patient years of follow-up. The only modifiable adjusted predictor for microalbuminuria was high HbA1c concentrations (hazard ratio per 1% rise in HbA1c 1.39, 1.27 to 1.52). Blood pressure and history of smoking were not predictors. Microalbuminuria was persistent in 48% of patients. Cumulative prevalence of progression from microalbuminuria to macroalbuminuria was 13.9% (12.9% to 14.9%); progression occurred at a mean age of 18.5 (5.8) years. Although the sample size was small, modifiable predictors of macroalbuminuria were higher HbA(1c) levels and both persistent and intermittent microalbuminuria (hazard ratios 1.42 (1.22 to 1.78), 27.72 (7.99 to 96.12), and 8.76 (2.44 to 31.44), respectively).

CONCLUSION

In childhood onset type 1 diabetes, the only modifiable predictors were poor glycaemic control for the development of microalbuminuria and poor control and microalbuminuria (both persistent and intermittent) for progression to macroalbuminuria. Risk for macroalbuminuria is similar to that observed in cohorts with adult onset disease but as it occurs in young adult life early intervention in normotensive adolescents might be needed to improve prognosis.

Prepubertal onset of diabetes prevents expression of renal cortical connective tissue growth factor

Puberty unmasks or accelerates the nephropathy of diabetes mellitus (DM). We performed focused microarray analysis to test the hypothesis that one or more genes in the transforming growth factor beta (TGF-beta) signaling system would be differentially regulated in male rats depending on their age at onset of DM. Littermates were started on the 6-week protocol at 4 weeks or 14 weeks of age. Renal cortical RNA was isolated and analyzed using gene chips with more than 30,000 transcripts. Age-specific effects of DM were demonstrated for 1,760 transcripts. Analysis then focused on 89 genes involved in the TGF-beta signaling pathway. Three of these genes showed age-dependent responses to DM, confirmed by quantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR). Connective tissue growth factor (CTGF) mRNA and protein were both increased approximately 30% in the renal cortex 6 weeks after adult-onset DM, with no alteration in either parameter after juvenile onset. Follistatin and avian myelocytomatosis viral oncogene homolog mRNA both showed a similar age-related pattern of response to DM, but protein levels did not parallel mRNA for either of these gene products. Given the known roles of CTGF in progressive nephropathies, it is an attractive candidate to explain pubertal acceleration or unmasking of the kidney disease of diabetes.

Atrial natriuretic peptide increases urinary albumin excretion in people with normoalbuminuric type-2 diabetes

BACKGROUND

Atrial natriuretic peptide (ANP) is elevated in patients with type-2 diabetes and microalbuminuria. The purpose of this study is to evaluate if ANP increases Urinary Albumin Eaxcretion Rate (UAER) in type-2 diabetes.

METHODS

Eight normoalbuminuric diabetic subjects underwent a randomised single blind study of 60 min intravenous infusion of ANP or vehicle. Eight non-diabetic controls underwent ANP infusion alone. Seven normoalbuminuric type-2 diabetes subjects received further ANP infusions during euglycaemia and during hyperglycaemia.

RESULTS

ANP increased urinary sodium (191.3 +/- 80.7 to 529.2 +/- 263.4 mumol/min, mean +/- SD, and P < 0.001) and UAER (72.2 +/- 73.4 to 224.9 +/- 182.9.5 mug/min, and P < 0.01) in diabetic subjects. In controls, UAER did not change significantly (P = 0.16); however, the natriuretic response to ANP was similar to diabetic subjects (P = 0.98). Hyperglycaemic did not enhance the albuminuric response to ANP (P = 0.88).

CONCLUSION

ANP increases UAER in normoalbuminuric type-2 diabetic subjects.

School performance in children with type 1 diabetes--a population-based register study

AIMS/HYPOTHESIS

We examined the school marks of diabetic children in Sweden at the time of leaving compulsory education. Marks were examined in comparison with non-diabetic children and with special regard to age at onset of diabetes.

SUBJECTS AND METHODS

The study involved 5,159 children who developed diabetes between 1 July 1977 and 1 July 2000, and 1,330,968 non-diabetic children. We linked the nationwide Swedish Childhood Diabetes Register to the Swedish School-Mark Register, which contains school marks for all children in Sweden at the time of leaving compulsory education (usually at 16 years old). Adjustment was made for potential confounders such as year of birth, maternal age, parity and educational level.

RESULTS

The mean of all numerical school marks for diabetic children was slightly but statistically significantly lower than those of the referent children (3.15 +/- 0.01 [mean + SD] vs 3.23, p < 0.001). The lowest mean score was among children with diabetes diagnosis before the age of 2 years (2.97 +/- 0.09 vs 3.08-3.17 in the older age groups, p = 0.10). When individual subjects were studied (sports, mathematics, English and Swedish), a more complex picture emerged. In four subjects (mathematics, English, Swedish and sports) the risk of a diabetic child not getting a school mark or not passing was increased; in sports and English the diabetic children had significantly reduced odds of getting a high mark.

CONCLUSIONS/INTERPRETATION

Despite a well-developed diabetes care system, we have not succeeded in preventing the disease from affecting school achievements. Among children with a young age at onset and therefore longer duration, the negative effects tend to be greater.

Serum and urinary nitrites and nitrates and Doppler sonography in children with diabetes

OBJECTIVE

The aim of the present study was to evaluate serum and urinary nitric oxide (NO) concentrations in children and adolescents with diabetes compared with age-matched healthy control subjects to find out whether Doppler ultrasonography could be used to detect changes in renal resistive indexes (RIs) in children with diabetes and to assess whether there are correlations between these parameters and NO excretion.

RESEARCH DESIGN AND METHODS

We studied 42 children with type 1 diabetes and 41 matched healthy control subjects, both divided into prepubertal or pubertal children. Serum and urinary nitrite and nitrate (NO2-+NO3-) concentrations were evaluated as an index of NO production. Doppler ultrasonographic registration of intrarenal RI was performed.

RESULTS

Compared with healthy control subjects, children with diabetes had significantly increased concentrations of serum (30.26 +/- 6.52 vs. 24.47 +/- 7.27 mmol/l, P = 0.001) and urinary NO2-+NO3- (345.07 +/- 151.35 vs. 245.86 +/- 80.25 mmol/l, P = 0.002); the same was true for Doppler RI values (0.64 +/- 0.03 vs. 0.60 +/- 0.04, P = 0.035). This occurs in both prepubertal and the pubertal children. A significant positive correlation was found between serum and urinary NO2-+NO3- levels (P = 0.002, r = 0.374). Serum NO2-+NO3- concentrations also correlated positively with Doppler RI (P = 0.032, r = 0.262) and HbA1c (A1C) (P = 0.004, r = 0.329); urinary NO2-+NO3- concentrations correlated positively with A1C (P = 0.001, r = 0.394). Doppler RI correlated positively with A1C (P = 0.000, r = 0.424).

CONCLUSIONS

This study demonstrates that in children with diabetes, chronic hyperglycemia may act through a mechanism that involves increased NO production and/or action and contributes to generating intrarenal hemodynamic abnormalities, which are detectable by Doppler ultrasonography even in early diabetic nephropathy.

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.

Age at onset of childhood-onset type 1 diabetes and the development of end-stage renal disease: a nationwide population-based study

OBJECTIVE

To analyze the impact of age at onset on the development of end-stage renal disease (ESRD) due to diabetic nephropathy in a nationwide population-based cohort with childhood-onset type 1 diabetes.

RESEARCH DESIGN AND METHODS

A record linkage between two nationwide registers, the Swedish Childhood Diabetes Registry, including 12,032 cases with childhood-onset diabetes, and the Swedish Registry for Active Treatment of Uraemia was performed. Log-rank test was used to test differences between cumulative risk curves of developing ESRD due to diabetic nephropathy in three different strata of age at onset (0-4, 5-9, and 10-14 years).

RESULTS

At a maximum follow-up of 27 years, 33 patients had developed ESRD due to diabetic nephropathy and all had a diabetes duration >15 years. In total, 4,414 patients had diabetes duration >15 years, and thus the risk in this cohort to develop ESRD was 33 of 4,414 (0.7%). A significant difference in risk of developing ESRD was found between the youngest (0-4 years) and the two older (5-9 and 10-14 years) age-at-onset strata (P = 0.03 and P = 0.001, respectively). A significant difference in the risk of developing ESRD was also found between children with prepubertal (0-4 and 5-9 years, n = 2,424) and pubertal (10-14 years, n = 2000) onset of diabetes (P = 0.002). No patient with onset of diabetes before 5 years of age had developed ESRD.

CONCLUSIONS

With a median duration of 21 years in this population-based Swedish cohort with childhood-onset diabetes, <1% of the patients had developed ESRD due to diabetic nephropathy, and a prepubertal onset of diabetes seems to prolong the time to development of ESRD.

Puberty and chronic kidney disease

Puberty is a period of dramatic physiologic changes when children become adults. Chronic kidney disease (CKD), like many disorders, may delay or blunt the onset and outcomes of puberty. These include attainment of adult height and reproductive capacity. Although nutrition and treatment effects may contribute to these phenomena, increasing evidence supports direct biological effects of CKD on the neurohypophyseal axis that controls these systems. Although CKD affects puberty, this life period also impacts the progression of CKD. Diabetes mellitus, posterior urethral valves, reflux nephropathy, and hypoplasia all appear to accelerate with sexual maturation. Potential mechanisms include increases in blood pressure and body size as well as altered endocrine physiology. Better understanding of the interactions of puberty and CKD may lead to better outcomes for children with CKD as well as longer preservation of native kidney function.

Pediatric aspects of diabetic kidney disease

Type 1 diabetes mellitus (DM1) commonly occurs in childhood, although many pediatric centers are now seeing more cases of type 2 diabetes (DM2). Kidney failure caused by either type of diabetes is uncommon during childhood, but these years of hyperglycemia contribute to long-term complications. All children with diabetes warrant screening of glomerular filtration rate, blood pressure, and urine albumin excretion. Screening should begin after 5 years of DM1 or at puberty. A similar screening strategy should start at the time of diagnosis of DM2. Atypical features such as dipstick positive proteinuria or active urine sediment may warrant referral to a nephrologist for evaluation, including biopsy. The first line of treatment in either form of diabetes is achieving the best glycemic control possible. Patients developing microalbuminuria or hypertension should receive antiangiotensin II drugs. Adult studies suggest blood pressure goals should be lower in diabetes than in the general population. Although direct evidence is not yet available in children, achieving blood pressure below the 90th percentile for age, height, and gender seems prudent. Longitudinal studies and new screening tests may allow detection of susceptible children earlier in the course of DM1 or DM2, perhaps allowing prevention of diabetic kidney disease.

Rates of diabetes mellitus-related complications in a contemporary adolescent cohort

BACKGROUND

Ten years after the Diabetes Control and Complications Trial there is a paucity of data as to what are current rates of diabetes-related complications in adolescence.

OBJECTIVE

To assess the incidence of diabetes-related complications in a contemporary cohort of adolescents with type 1 diabetes mellitus.

DESIGN

Retrospective cross-sectional survey.

PATIENTS

Adolescents aged >10 years with type 1 diabetes mellitus for >5 years from the Royal Children's Hospital, Melbourne Diabetes Clinic.

RESULTS

382 patients were studied (191 male). The mean HbA1c for males was 8.72% and for females was 8.80%. The rates of hypothyroidism and hypercholesterolaemia were 1.5% and 22% respectively. Twenty-five patients (8%) had intermittent microalbuminuria and six (2%) had persistent microalbuminuria. Only one patient had macroalbuminuria (0.3%). Only two patients (0.7%) with mild non-were diagnosed proliferative diabetic retinopathy. Coeliac disease was diagnosed in 6% of patients.

CONCLUSIONS

In this representative and contemporary cohort of diabetic adolescents the incidence of microvascular diabetes-related complications is quite low.

Childhood precursors of adolescent outcomes in type 1 diabetes mellitus

Contemporary outcome measures of chronic illnesses such as type 1 diabetes mellitus are broader than those clinical outcomes traditionally assessed in therapeutic encounters. A holistic approach emphasises quality of life and emotional well-being as well as the achievement of optimal disease management. This paper reviews current knowledge about growth, metabolic control, diabetes complications, neurocognitive and psychological outcomes as well as health-related quality of life in childhood diabetes mellitus. It is suggested that the antecedents of adverse diabetes and psychological outcomes in adolescence lie in the years prior to adolescence. The model of care in childhood diabetes mellitus must be focussed on earlier screening and intervention if adverse outcomes are to be reduced.

The significance of the prepubertal diabetes duration for the development of retinopathy and nephropathy in patients with type 1 diabetes

OBJECTIVE

A Danish nationwide prospective cohort of children and adolescents with type 1 diabetes was followed for 8 years to study the effect of the prepubertal duration of diabetes on early retinopathy and elevated albumin excretion rate (AER) (>20 microg/min).

RESEARCH DESIGN AND METHODS

In 1989, blood glucose control (HbA(1c)) and AER was investigated in approximately 80% of all Danish children and adolescents with type 1 diabetes. A cohort of 339 young patients were restudied in 1995 including physical examination, demographic data, HbA(1c), AER, and fundus photography with central reading. Among the patients, a number of 304 had a prepubertal onset of diabetes defined as an onset age less than 11.7 years in girls and 12.9 years in boys. Microalbuminuria was defined as an AER of 20-150 microg min(-1) and macroalbuminuria as AER >150 microg min(-1) in two out of three timed overnight urine samples.

RESULTS

At the follow-up in 1995-1996, no patients were younger than 12 years of age. The prevalence of any level of retinopathy was 17.7% in the age group 12-15 years, 45.4% from 16 to 20 years, and increased to 67.6% in patients more than 20 years of age. Diabetic retinopathy was significantly associated to poor long-term metabolic control (HbA(1c)) (P<.0001) and to diabetes duration both in patients with a prepubertal onset of disease as well as patients with a pubertal (P<.001) onset of disease. However, the pubertal diabetes duration contributed two times more than the prepubertal diabetes duration. Mean postpubertal diabetes duration to any retinopathy was significantly shorter (9.4 years) in patients with prepubertal onset of the disease compared to patients with postpubertal onset (11.8 years) (P=.0004). In total, the prevalence of elevated AER (>20 microg/min) increased from 4% in 1989 to 13% in 1995. None of the patients younger than 15 years of age had elevated AER, while the prevalence of elevated AER was about 14% from 15 years of age and onwards. Elevated AER in 1995 was significantly related to long-term metabolic control (P<.001) and elevated AER in the preceding years (P<.001) but was not correlated to diabetes duration neither before nor after the age of 12 years.

CONCLUSION

The prepubertal diabetes duration is significantly associated with the development of diabetic retinopathy. The period, however, contributes less compared to the years after puberty. In concert with other studies, we found no association between raised AER and diabetes duration. This may be explained by the fact that other factors are more significant and dilute the significance of diabetes duration. Nonetheless, it seems prudent to optimise blood glucose control irrespective of age.

Early glycemic control, age at onset, and development of microvascular complications in childhood-onset type 1 diabetes: a population-based study in northern Sweden

OBJECTIVE

The aim of this work was to study the impact of glycemic control (HbA(1c)) early in disease and age at onset on the occurrence of incipient diabetic nephropathy (MA) and background retinopathy (RP) in childhood-onset type 1 diabetes.

RESEARCH DESIGN AND METHODS

All children, diagnosed at 0-14 years in a geographically defined area in northern Sweden between 1981 and 1992, were identified using the Swedish Childhood Diabetes Registry. From 1981, a nationwide childhood diabetes care program was implemented recommending intensified insulin treatment. HbA(1c) and urinary albumin excretion were analyzed, and fundus photography was performed regularly. Retrospective data on all 94 patients were retrieved from medical records and laboratory reports.

RESULTS

During the follow-up period, with a mean duration of 12 +/- 4 years (range 5-19), 17 patients (18%) developed MA, 45 patients (48%) developed RP, and 52% had either or both complications. A Cox proportional hazard regression, modeling duration to occurrence of MA or RP, showed that glycemic control (reflected by mean HbA(1c)) during the follow-up was significantly associated with both MA and RP when adjusted for sex, birth weight, age at onset, and tobacco use as potential confounders. Mean HbA(1c) during the first 5 years of diabetes was a near-significant determinant for development of MA (hazard ratio 1.41, P = 0.083) and a significant determinant of RP (1.32, P = 0.036). The age at onset of diabetes significantly influenced the risk of developing RP (1.11, P = 0.021). Thus, in a Kaplan-Meier analysis, onset of diabetes before the age of 5 years, compared with the age-groups 5-11 and >11 years, showed a longer time to occurrence of RP (P = 0.015), but no clear tendency was seen for MA, perhaps due to lower statistical power.

CONCLUSIONS

Despite modern insulin treatment, >50% of patients with childhood-onset type 1 diabetes developed detectable diabetes complications after approximately 12 years of diabetes. Inadequate glycemic control, also during the first 5 years of diabetes, seems to accelerate time to occurrence, whereas a young age at onset of diabetes seems to prolong the time to development of microvascular complications.

Insulin treatment in children and adolescents

The management of diabetes in children presents a number of challenges. The ideal is to achieve optimal glycaemic control using an insulin regimen that is acceptable to the child and family, which improves glycaemic control, whilst avoiding hypoglycaemia. The paediatric population differ from their adult counterparts in several ways, such as variability of exercise and eating patterns, and the hormonal influences of puberty, which means that the insulin regimen must be tailored to suit an individual child and their family.

CONCLUSION

This review will focus on the particular difficulties of managing diabetes in children and, in particular, the problem of avoiding hypoglycaemia while maintaining adequate glycaemic control.

The long-term renal and retinal outcome of childhood-onset Type 1 diabetes

AIMS

To quantify the influence of childhood onset on long-term renal and retinal outcome in Type 1 diabetes.

METHODS

We used a population-based diabetes register to identify all Type 1 patients diagnosed before age 15 from 1960 to 1982 and resident in a defined catchment area in 1999. Those diagnosed before age 5, aged 5-9 and 10-14 years were compared with a reference group diagnosed at age 21-25 years over the same period.

RESULTS

Compared with adult-onset controls, proteinuria occurred earlier (P = 0.02) and nephropathy outcome was worse (P = 0.008) in childhood-onset diabetes. The risk of developing microalbuminuria was greater in childhood-onset diabetes: odds ratio 2.6 (95% confidence interval 1.4-4.9, P = 0.003). The relative risk of established nephropathy was 3.8 (1.5-9.4, P = 0.005) with childhood onset. The number developing background retinopathy did not differ with age at onset but younger onset patients were more likely to need laser treatment: relative risk 2.1 (1.1-3.8, P = 0.02). This maintained visual outcome which was not significantly different between the various age at onset groups.

CONCLUSIONS

Patients with onset of Type 1 diabetes before age 15 have substantially worse renal outcome and require more laser treatment than adult-onset patients. Differences between those with onset before age 5, onset at 5-9 and 10-14 years are small compared with the difference between childhood onset and adult onset. Events in the teenage years therefore appear to have a major adverse effect on the risk of developing long-term microvascular complications.

Signs of nephropathy may occur early in young adults with diabetes despite modern diabetes management: results from the nationwide population-based Diabetes Incidence Study in Sweden (DISS)

OBJECTIVE

To estimate the occurrence of early-onset renal involvement in a nationwide population-based cohort of young adults with diabetes in Sweden and relate the findings to glycemic control, type of diabetes, sex, smoking, and blood pressure.

RESEARCH DESIGN AND METHODS

The Diabetes Incidence Study in Sweden aims to register all incident cases of diabetes in the age-group 15-34 years. In 1987-1988, 806 patients were reported and invited to participate in a follow-up study focusing on microvascular complications. Of them, 469 subjects participated. The assessment was based on questionnaires (n = 469), blood samples (n = 424), urine samples (n = 251) and, when appropriate, medical records (n = 186).

RESULTS

During the follow-up time, median 9 years (range 6-12), 31 of 469 patients (6.6%) with incipient or overt diabetic nephropathy (i.e., micro- or macroalbuminuria) were found, 24 of 426 (5.6%) in type 1 and 7 of 43 (16%) in type 2 diabetic subjects (P = 0.016). Additionally, 24 of 31 patients (77%) had microalbuminuria and 7 (23%) had macroalbuminuria, which mainly occurred in patients with type 2 diabetes. In a Cox regression analysis, high mean HbA(1c) during the follow-up period and high blood pressure at follow-up increased the risk of developing signs of nephropathy (P = 0.020 and P = 0.003, respectively). Compared with patients with type 1 diabetes, those with type 2 diabetes tended to have an increased risk of renal involvement (P = 0.054) when adjusting for sex, tobacco use, glycemic control, and blood pressure.

CONCLUSIONS

Despite modern treatment and self-monitoring of blood glucose, young adult patients with diabetes may still develop renal involvement during the first 10 years of diabetes duration. Inadequate HbA(1c), high blood pressure, and type 2 diabetes appear to be risk markers for early occurrence of diabetic nephropathy.

Description of microangiopathy in children with type 1 diabetes mellitus: a 19-year retrospective study

BACKGROUND

The aim of the study was to estimate the outcome of patients with type 1 diabetes followed in a university hospital in the paediatric department and then in the adult diabetic department for at least 10 years.

METHODS

We made a retrospective analysis of 50 patients (28 women and 22 men) with type 1 diabetes with disease duration of 19 +/- 6 years and analysed whether retinopathy and nephropathy had progressed, had remained unchanged or had improved or normalised.

RESULTS

The mean age of diabetes onset was 8 +/- 4 years (1-16). Ketoacidosis revealed diabetes in 36% of the children. Mean HbA(1c) was 8.6 +/- 1.8%, and was over 8.5% in 34% of the patients. The mean age at onset of puberty (Tanner stage II) was 12 +/- 1 years in girls and 13 +/- 1 years in boys. Mean HbA(1c) was 7.9 +/- 1.2% during the year before onset of puberty and 8.7 +/- 1.1% in the following 3 years, corresponding to a 10% pubertal increase in HbA(1c). Retinopathy was seen in 50% of the patients at a mean age of 22 +/- 5 years, 15 +/- 6 years after onset of diabetes. Mean HbA(1c) was 9.7 +/- 1.6% in patients with proliferative retinopathy, 9.0 +/- 1.5% in patients with non proliferative retinopathy, and 8.1 +/- 1.3% in those without (p=0.02, proliferative versus no retinopathy, p > 0.05 non proliferative versus no retinopathy). Microalbuminuria was diagnosed in 26% of the patients. Mean HbA(1c) was 9.3 +/- 2.1% in patients with microalbuminuria versus 8.1 +/- 1.3% in those with normoalbuminuria (p=0.02).

CONCLUSIONS

Glycemic control was similar in patients with non proliferative retinopathy and those without. Proliferative retinopathy and nephropathy were both related to the level of 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.

Treatment of hypertension and microalbuminuria in children and adolescents with type 1 diabetes mellitus

Nephropathy is the main cause of morbidity and mortality in patients with type 1 diabetes and, in adults, persistent microalbuminuria is the best marker of the consequent risk for its development. In the pediatric population, puberty represents the most important risk factor for the development of microangiopathic complications, although it is not necessarily associated with the progression to frank proteinuria. As many as 50% of subjects may revert to normoalbuminuria. Hypertension is a further risk factor and may accelerate the progression of micro- and macrovascular complications. There is evidence that angiotensin-converting enzyme (ACE) inhibitors reduce renal damage by one or more mechanisms independent of their antihypertensive effects--hence they represent the drug of choice for the treatment of diabetic nephropathy. However, as angiotensin II receptor antagonists are more specific, they may become the obvious treatment choice in the near future. There is no consensus as to who should be treated and when treatment with renoprotective drugs should begin in the pediatric population, due to the lack of a clear definition of the natural history of microalbuminuria in this age group. In this review some models and controversial aspects of this issue are presented and discussed.

Detection of serum collagen type IV in children with type 1 (insulin-dependent) diabetes mellitus--a longitudinal study

The basement membrane is a major focus of scientific interest because of its role in a variety of diseases. In diabetes mellitus, a thickening of the capillary basement membrane results in microangiopathic lesions. To monitor the metabolism of the basement membrane protein collagen type IV (CIV) in diabetes mellitus, serum levels of CIV were measured using an enzyme-linked immunosorbent assay (ELISA) method in 28 children with type 1 diabetes mellitus over a period of 6 years. These values were compared to serum CIV levels in 24 age and sex matched controls. In the first 3 years, serum CIV levels were normal. In the 4th year, 1 patient and in years 5 and 6, 4 patients had increased CIV serum levels. At the end of the investigation, 3 children had developed retinopathy, 6 microalbuminuria, and 2 both microalbuminuria and retinopathy. Only those patients with microalbuminuria had increased CIV serum levels. In conclusion, we suggest that CIV serum levels can be used as a marker for the development of diabetic microalbuminuria.

Psychosocial issues in pediatric diabetes

Although the majority of diabetic patients exhibit mild depression, anxiety, and somatic complaints at the time of diagnosis, these symptoms are usually temporary and resolve within 6 to 9 months. However, in some patients, depressive symptoms may increase with the duration of diabetes. Anxiety seems to increase and to be more prevalent in girls than in boys. Depression and self-esteem problems have a negative impact on the adaptation to diabetes and metabolic control. Patients' adjustment to diabetes shortly after diagnosis seems to predict adjustment later on. Family characteristics have major implications in the patient's adjustment to diabetes, self-management, and quality of life. Children and adolescents living in families with a high degree of conflict or that are less caring appear to have poorer metabolic control. Thus, the goal of achieving metabolic and psychological stability requires a diabetes team equipped to provide social and psychological support in addition to the development of technical skills. This includes very early assessment of family dynamics and psychological intervention.

Longitudinal study of urinary albumin excretion in young diabetic patients--Wessex Diabetic Nephropathy Project

AIMS

This study was established to follow changes in albumin/creatinine ratio (ACR) and to determine the prevalence and degree of progression of microalbuminuria (MA) or of clinical proteinuria (CP) in children with Type 1 diabetes. The study has investigated subjects for up to 12 years in establishing the correlation between MA and gender, age, duration of diabetes and glycated haemoglobin (HbA1c). The study has defined clinical cut-offs for MA in daytime clinic urine samples in young diabetic subjects.

METHODS

Three hundred and sixty-one patients were involved in the study, with 221 (61.2%) having over six sets of data. Urine samples were collected at routine annual clinic visits and analysed without prior freezing for ACR. Blood samples were taken for HbA1c measurement. Data including sex, age and duration of diabetes were recorded.

RESULTS

A random clinic ACR of < 4.5 mg/mmol (males) and 5.2 mg/mmol (females) creatinine was used as the 'clinical cut-off' to define the presence of MA. The presence of MA was independent of HbA1c and duration of diabetes but appeared be associated with the adolescent years (> 10 years). There was little evidence of progression from normoalbuminuria to MA, or from MA to CP. Of patients aged 10-18 years, 30.9% of males and 40.4% of females had one or more episodes of MA.

CONCLUSIONS

Persistent MA and random episodes of MA or CP may be associated with the adolescent years but not with duration of diabetes. Further study will reveal if the substantial increases in ACR sometimes seen during adolescence are predictive of diabetic nephropathy. Clinical cut-offs of < 4.5 and < 5.2 mg/mmol creatinine for males and females, respectively, are suggested for the interpretation of changes in ACR in random urine samples in young people with Type 1 diabetes.

Blood pressure does not rise before the onset of microalbuminuria in children followed from diagnosis of type 1 diabetes. Oxford Regional Prospective Study Group

OBJECTIVE

To examine whether a rise in blood pressure could be detected before the onset of microalbuminuria (MA) in a cohort of children followed from diagnosis of type 1 diabetes.

RESEARCH DESIGN AND METHODS

The Oxford Regional Prospective Study is an incident cohort study of children with type 1 diabetes aged (mean +/- SD) 9.8 +/- 3.7 years at diagnosis. Subjects were assessed annually from diagnosis, with measurement of HbA1c, arterial blood pressure (random zero), and three urine samples for estimation of the albumin/creatinine ratio. During follow-up, 63 of 494 children developed MA at one or more annual assessments and were designated as cases for a nested case-control study. Each case was matched for sex and age at diagnosis with two normoalbuminuric control subjects. Blood pressure (BP) data were compared at corresponding years of diabetes duration.

RESULTS

Cases with MA were similar to normoalbuminuric control subjects with respect to age and BMI, but they had higher mean HbA1c levels (mean difference 1.1%, P < 0.001). In the years before the onset of MA, the diastolic BP standard deviation score (SDS) was significantly higher than zero in cases (mean 0.49, P < 0.001) and in control subjects (0.50, P < 0.001). No difference could be detected between cases and control subjects before the onset of MA in either systolic or diastolic BP (mean difference systolic -1.2 mmHg [95% CI -4.7 to 2.7], mean difference diastolic 0.1 mmHg [-2.4 to 2.6]). However, within the cases, the onset of MA was associated with elevations in systolic and diastolic BP SDSs (F = 16.1, P < 0.001; and F = 18.0, P < 0.001). BMI, but not HbA1c, was associated with systolic and diastolic BP SDSs in the subjects with MA (F = 0.6, P = 0.4; and F = 12.3, P = 0.001). However, the association of BP with MA remained signifcant for systolic BP (P = 0.001) and for diastolic BP (P < 0.001) after adjusting for BMI.

CONCLUSIONS

A rise in systemic BP cannot be detected before the first appearance of MA in children with type 1 diabetes. BP rises concurrently with the onset of MA and is also closely related to BMI.

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.

Prevalence of abnormal urinary albumin excretion in adolescents and children with insulin dependent diabetes: the MIDAC study. Microalbinuria in Diabetic Adolescents and Children (MIDAC) research group

OBJECTIVE

To examine the prevalence of microalbuminuria, defined as an albumin to creatinine ratio (UAC) equal to or greater than 2 mg/mmol in at least two of three early morning urine samples, in adolescents and children with insulin dependent diabetes mellitus.

DESIGN

Centrally coordinated, cross sectional, multicentre study in paediatric diabetes outpatient clinics in the United Kingdom and Republic of Ireland.

METHODS

Blood and urine samples collected between July 1997 and July 1998 were analysed at a central reference laboratory for HbA(1C) using high performance liquid chromatography, and for urinary albumin and creatinine concentrations from which the UAC was derived (mg/mmol). Clinical data were collected locally and coordinated centrally.

SUBJECTS

Patients, aged between 10 and 20 years, with insulin dependent diabetes mellitus for more than a year, attending diabetes outpatient clinics.

RESULTS

A total of 1007 patients, comprising 69% of the eligible population of 1451, provided three early morning urine samples. Ninety eight (9.7%) had microalbuminuria using the currently accepted screening cut off of UAC >/= 2 mg/mmol in at least two of three early morning urine samples. Significantly more girls than boys and significantly more pubertal and postpubertal patients had abnormal albumin excretion. Microalbuminuria was not associated with raised blood pressure.

CONCLUSIONS

A prevalence of 9.7% for abnormal UAC was found in a cohort of 1007 children and adolescents aged 10-20 years. Thus a tenth of this national sample of young people were identified as being at particular risk of microvascular and later macrovascular disease.

Freezing method affects the concentration and variability of urine proteins and the interpretation of data on microalbuminuria. The Oxford Regional Prospective Study Group

AIMS

Microalbuminuria and, to a lesser extent, renal tubular proteins are widely used in the early detection of incipient nephropathy in diabetes mellitus. Recent reports have indicated detrimental effects of storage at -20 degrees C on urine proteins. This study investigated the effects of storage on the measurement of urine proteins and discusses implications for the interpretation of data.

METHODS

Two-hundred and sixty-eight specimens, collected from children with Type 1 diabetes, split into duplicate aliquots and stored at -20 degrees C and -70 degrees C, respectively, for 6-8 months, were analysed for albumin, retinol binding protein, N-acetyl glucosaminidase and creatinine, in the same assays to eliminate inter-assay variability. Two independent non-diabetic cohorts of children provided urine specimens, which were stored at -20 degrees C for one cohort and -70 degrees C for the other, to determine normal ranges for urine proteins.

RESULTS

Storage at -20 degrees C led to a variable underestimation of all three urine proteins in 20% of specimens. Creatinine was unaffected. This underestimation was greater in more concentrated urine (r2 = 0.38, P < 0.001, n = 262). Consequently storage at -20 degrees C increased the variance of the albumin/ creatinine ratio more than the variance of albumin concentration. Temperature of storage affected the normal range, which was 0.1-2.1 mg/mmol at -20 degrees C compared to 0.3-3.1 mg/mmol at -70 degrees C. The prevalence of microalbuminuria (> 2SD above the geometric mean in non-diabetic specimens stored at -20 degrees C) was 27% after storage at -70 degrees C vs. 24% after -20 degrees C. The prevalence of microalbuminuria (>2SD above the geometric mean in nondiabetic specimens stored at -70 degrees C) was 21% after storage at -70 degrees C vs. 17% after -20 degrees C.

CONCLUSIONS

Urine proteins are significantly but variably underestimated after storage at -20 degrees C. These effects account for increased variance and differences in the normal range, but have less effect on the detection of microalbuminuria than might be predicted.

The prevalence of incipient tubular dysfunction, but not of glomerular dysfunction, is increased in patients with diabetes onset in childhood

The study investigated the prevalence of incipient renal dysfunction in two cohorts with identical duration of type I diabetes but with childhood or adult onset of the disease. The pattern of glomerular (albumin, alb) and tubular (alpha(1)-microglobulin, alpha(1)-m, and N-acetyl-beta-D-glucosaminidase, NAG) urinary protein excretion was studied in 97 patients with diabetes onset before the age of 16 years and in 53 patients with manifestation of the disease after this age. Diabetes duration was comparable in both groups [9.0 years (1.5-40.0) versus 9.0 (1.0-34.0), p 30 microg/g creatinine), patients with diabetes onset in childhood showed significantly higher excretion of NAG compared to those with diabetes onset after the age of 16. The excretion of both tubular markers (alpha(1)-m and NAG) correlated significantly with HbA(1c)-values in both groups. In multiple regression analysis, tubular proteinuria (alpha(1)-m) and diabetes duration correlated significantly to microabuminuria (multiple R = 0.60, p < 0.001). These data suggest that there is no difference concerning the prevalence of incipient diabetic glomerulopathy between patients with an early or a late onset of diabetes. However, a more frequent impairment of tubular function was found in young patients with diabetes onset in childhood, which might be due to a non-optimal glycemic control in this population.

Inter-relação de variáveis demográficas, terapêutica insulínica e controle glicêmico em pacientes com diabetes mellitus do tipo 1 atendidos em um hospital universitário

Com o objetivo de avaliar a inter-relação das variáveis demográficas, terapêutica insulínica e controle glicêmico no diabetes do tipo 1 (DM1), foram estudados 86 pacientes (44 F / 42 M), de 21,8±10 anos, 10 (11,6%) pré-púberes, 22 (25,6%) púberes e 54 (62,8%) adultos, com duração do DM de 8,6±7,1 ano e idade do diagnóstico de 13,2±8,5 anos, acompanhados durante o ano de 1997. O número de consultas anuais foi de 3,6±2,2, sem associação com sexo, raça e estágio de Tanner. A dose de insulina total foi de 0,9±0,4 U/kg/dia sendo que 72 deles (83,7%) utilizavam duas injeções por dia; 39 (45,3%) utilizavam insulina de ação rápida dos quais 36 (92,3%) em combinação com insulina de ação intermediária matinal. Na análise de regressão múltipla apenas a HbA1C influenciou a dose de insulina (r=0,45; r²=0,21; p<0,001). A HbA1C foi de 8,4±1,9%, sendo os maiores níveis observados no estágio 4, em comparação aos estágios 1, 2, 3 e 5 de Tanner, respectivamente (10,5±2,4 vs 7,6±1,4 vs 8,9±2,1 vs vs 8,3±2,4 vs 8,2±1,8%; p= 0,02). As adolescentes apresentaram maior HbA1C e IMC que os adolescentes: 10,5±2,5 vs 8,3±2,0% (p= 0,02) e 19,4±1,9 vs 18,3±2,2 kg/m² (p= 0,04), respectivamente. O controle glicêmico foi considerado bom em 50% e péssimo em 31,4% dos pacientes. Concluímos que na amostra estudada houve uma piora do controle glicêmico no estágio final da puberdade, independente do número de consultas e das variáveis demográficas analisadas, e que o elevado número de pacientes com controle péssimo deverá nortear mudanças das estratégias terapêuticas.

Variabilidade da pressão arterial de consultório em pacientes com diabetes mellitus do tipo 1

Objetivo: Analisar a associação da variabilidade da pressão arterial auscultatória sistólica (PAS) e diastólica (PAD) com variáveis clínicas do diabetes tipo 1 (DM1). Métodos: Foram estudados 58 pacientes com DM1 (33 mulheres) com 24,6±8,5 (9-43) anos e duração do diabetes de 8,4±6,6 (0,4-36) anos, sendo 46 adultos e 12 púberes. A PAS e a PAD foram aferidas em três diferentes dias na posição supina, antes e após 5 e 10 min de repouso, calculando-se o coeficiente de variação médio (CVM) e intra-individual (CVI). Resultados; O CVM da PAS entre os diferentes tempos de aferição variou de 3,0 a 3,6% (adultos) e 3,3 a 4,6% (púberes) e o da PAD de 5,5 a 6,6% (adultos) e 6,3 a 7,4% (púberes).O CVM da PAS entre os diferentes dias de aferição variou de 6,4 a 6,8% (adultos) e 8,7 a 9,2% (púberes), sendo o CVI da PAS sem e após 5 min de repouso maior em púberes do que adultos, respectivamente (8,1 ±3,1 vs 5,3±4,1%; p=0,004) e (7,9±4,7 vs 5,2±3,7%; p=0,02) e apresentando uma maior correlação com a idade (PAS antes e após 5 min de repouso, respectivamente r= -0,34; r2= 0,12; p=0,007 e r= -0,31; r2= 0,09; p=0,01. O CVM da PAD entre os diferentes dias de aferição variou de 9,7 a 10,1% para os adultos e de 13 a 14,2% para os púberes. Nos adultos observamos diminuição da PAS e PAD entre os diferentes tempos de aferição e uma maior correlação entre duração do diabetes e PAS final após 5 min (r = 0,39; r2 = 0,15; p=0,007) e PAD após 10 min de repouso (r= 0,36; r2 = 0,13; p= 0,01). Conclusão: A variabilidade da PAS e PAD entre os diferentes dias e tempos de aferição observados neste estudo justificam a necessidade da realização de várias aferições após repouso de até 10 min em ambiente apropriado para o acompanhamento ambulatorial de rotina do paciente com DM1.

Metabolic control and prevalence of microvascular complications in young Danish patients with Type 1 diabetes mellitus. Danish Study Group of Diabetes in Childhood

AIMS

After Danish nationwide investigations (1987, 1989) demonstrated unacceptable blood glucose control in unselected young diabetic patients, we set out to estimate the present glycaemic control and the prevalence of microvascular complications in a cohort of children and adolescents participating in the two previous studies.

METHODS

This follow-up represents 339 patients (47% of the inception cohort), median age 21.1 years (range 12.0-26.9), median diabetes duration 13.2 years (range 8.9-24.5). A standardized questionnaire, fundus photographs (with central reading) and a physical examination were performed. HbA1c and overnight albumin excretion rate (AER) were analysed centrally.

RESULTS

Although 88% (n= 309) of the young persons were treated with three or more daily insulin injections, HbA1c (nondiabetic range 4.3-5.8, mean 5.3%) was 9.7+/-1.7% (mean+/-SD). Males had higher HbA1c values than females (P < 0.015). Mean daily insulin dose was 0.92+/-0.25 IU.kg(-1).24h(-1). Microalbuminuria (AER > 20-150 microg/min) and macroalbuminuria (AER > 150 microg/min) were found in 9.0% and 3.7% of the patients, respectively, and was associated with increased diastolic blood pressure (P<0.01) and presence of retinopathy (P<0.01). Retinopathy was present in approximately 60% of the patients and was associated with age, diabetes duration, HbA1c, diastolic blood pressure and AER (all P<0.01). Subclinical neuropathy (vibration perception threshold by biothesiometry > 6.5 V) was found in 62% and showed a significant association with age, linear height, diastolic blood pressure (all P < 0.01) and diabetic retinopathy (P = 0.01).

CONCLUSIONS

In spite of the majority of the patients being on multiple insulin injections, only 11% had HbA1c values below 8% and the prevalence of diabetic microvascular complications in kidneys, eyes and nerves was unacceptable high.

Quality of paediatric IDDM care in Germany: a multicentre analysis. German Paediatric Diabetology Group

Quality management has been applied in recent years to improve the care of children and adolescents with insulin dependent diabetes mellitus (IDDM). In 1995 the German Paediatric Diabetology Working Group published standards on quality control, in which relevant parameters on structure, process and outcome of care were defined. A computer software programme-developed at the University of Ulm under the auspices of the German Secretary of Health-has been used for quality control with central anonymous analysis in a nationwide survey. Data from 23 paediatric centres with 2407 patients seen between January and June 1996 were evaluated. The results showed an admission rate to hospital of 23.8 per 100 patient-years with an average duration of in-patient stay of 2.74 days/year. 80% of the patients were treated with an intensive insulin therapy regimen comprising three or more injections daily. The overall metabolic control was reasonably good with a mean HbA1c value of 7.8%. The rate of severe hypoglycaemia complicated by coma and/or convulsions was six per 100 patient-years and of ketoacidosis one per 100 patient-years. Unfortunately screening for diabetic retinopathy and nephropathy was not carried out consistently. The incidence was 44% and 33% respectively.

Practical aspects of managing diabetes in adolescents

In 1988 and 1990 screening for HbA1c and albumin excretion rate in diabetic children was carried out throughout Denmark. Each study included approximately 1000 diabetic patients. Raised levels of HbA1c (9.5-10%) were found despite 60% of these young people receiving three or more insulin injections daily. The prevalence of persistent microalbuminuria was 4.3%, which was associated only with age and diastolic blood pressure. A recent international survey of HbA1c and insulin treatment involving 2873 children found an average HbA1c of 8.6%+/-1.7%, which varied significantly (p < 0. 0001) between centres. Severe hypoglycaemia was related to a young age (0-8 y) and low HbA1c. There were no significant differences in glycaemic control between adolescents treated with two, three, four or more insulin injections daily. Adolescents on four or more injections received significantly (p < 0.001) more insulin. Girls receiving four or more injections had a significantly (p < 0.01) higher body mass index than girls on twice-daily insulin. Preadolescent children on premixed insulin showed similar HbA1c levels to those on a combination of short- and long-acting insulin, whereas in adolescents, significantly better HbA1c values were achieved with individual combinations. Despite intensive diabetes management, particularly in adolescence, near normoglycaemia is achieved only in a few individuals. control, glycosylated, haemoglobin

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.