Longitudinal patterns of glycemic control and diabetes care from diagnosis in a population-based cohort with type 1 diabetes. The Wisconsin Diabetes Registry

Young Adults With Type 1 Diabetes Preparing to Transition to Adult Care: Psychosocial Functioning and Associations With Self-Management and Health Outcomes

BACKGROUND | Young adulthood is a vulnerable developmental period associated with increased risk for suboptimal health outcomes in youth with type 1 diabetes. Psychosocial factors have been associated with self-management and glycemic control in younger populations, but the extent to which these associations exist among young adults is poorly understood. This study aimed to examine the psychosocial functioning of young adults with type 1 diabetes and associated clinical outcomes. METHODS | Participants included young adults (n = 44) between the ages of 18 and 23 years in a pediatric setting who were preparing to transition to adult care. All participants completed self-report measures of psychosocial functioning at baseline as part of this longitudinal observational study. Outcome data included glycemic control, frequency of blood glucose monitoring, and self-management ratings at baseline and 1-year follow-up. RESULTS | Young adults with type 1 diabetes reported higher levels of depressive symptoms, lower self-efficacy, and more risk behaviors compared with previously published scores for adolescents. Young adults also reported greater resilience and transition readiness than their younger counterparts. Psychosocial variables were differentially related to glycemic control and frequency of blood glucose monitoring both cross-sectionally and longitudinally. CONCLUSION | This study provides key information about the psychosocial functioning of young adults with type 1 diabetes. It identifies relevant psychosocial factors that are associated with meaningful health outcomes during the transition preparation period. These findings may inform the development of clinical programs aimed at promoting transition preparation and health outcomes in young adults with type 1 diabetes.

Design and baseline data from a PCORI-funded randomized controlled trial of family-centered tailoring of diabetes self-management resources

This article describes the methodology, recruitment, participant characteristics, and sustained, intensive stakeholder engagement for Project ACE (Achieving control, Connecting resources, Empowering families). Project ACE is a randomized controlled trial of children and youth ages 8-16 with type 1 diabetes evaluating the impact of tailored self-management resources on hemoglobin A1c (A1c) and quality of life (QOL). Despite strong evidence that controlling A1c reduces long-term complications, <25% of US youth with type 1 diabetes meet A1c targets. Many interventions are efficacious in improving A1c and QOL for these youth, whose families often struggle with the substantial demands of the treatment regimen. However, most such interventions are ineffective in the real world due to lack of uptake by families and limited healthcare system resources. Project ACE is a multi-site trial designed to improve diabetes outcomes by tailoring existing, evidence-based interventions to meet families' needs and preferences. We hypothesize that this family-centered approach will result in better A1c and QOL than usual care. Project ACE has recruited and randomized 214 eligible 8-16year old youth and their parents. The 9-month intervention consisted of 4 group sessions tailored to families' self-management barriers as identified by a validated instrument. Outcomes including A1c and QOL for parents and youth will be assessed for 1year after the intervention. Stakeholder engagement was used to enhance this trial's recruitment, retention and integration into routine clinical care. Findings will inform implementation and dissemination of family-centered approaches to address self-management barriers.

TRIAL REGISTRATION NUMBER

NCT02024750 Trial Registrar: Clinicaltrials.gov, https://clinicaltrials.gov/ct2/show/NCT02024750.

Factors Associated with Higher Pro-Inflammatory Tumor Necrosis Factor-α Levels in Young Women with Type 1 Diabetes

AIMS

While cytokines play a role in the etiology of type 1 diabetes, cytokines later in the disease are less understood. We therefore investigated associations of pro-inflammatory tumor necrosis factor-α levels measured at prolonged disease duration with C-peptide at diagnosis, long-term glycemic control, diabetes duration, clinical factors, and health behaviors.

METHODS

Data and blood were collected during an ancillary study to the longitudinal Wisconsin Diabetes Registry, a population-based cohort followed since diagnosis of type 1 diabetes. The ancillary study was conducted at 13-18 years diabetes duration, and enrolled premenopausal women age 18-45 years (n=87).

RESULTS

Higher tumor necrosis factor-α levels at 13-18 years diabetes duration were independently associated with longer duration (p=0.0004) and worse current renal function (p=0.02). Additionally, diabetes duration modified both of the positive associations of tumor necrosis factor-α levels (both interactions p≤0.01) with mean glycemic control during the previous 10 years (significant only in women with longer durations) and current daily caffeine intake (significant only in women with shorter durations). In women with C-peptide measured at diagnosis (n=50), higher tumor necrosis factor-α levels at 13-18 years duration were associated with lower C-peptide (p=0.01), independent of glycemic control during the previous 10 years.

CONCLUSIONS

Lower residual C-peptide at diagnosis and poor long-term glycemic control independently predicted higher pro-inflammatory tumor necrosis factor-α levels years later. The novel relationship with C-peptide needs confirmation in a larger cohort. Given the association between tumor necrosis factor-α and diabetes complications, further longitudinal studies may help clarify the potentially complex associations between glycemic control, inflammatory cytokines, and complications.

Glycaemic control and lipid concentrations in a cohort of people with diabetes over 7 years of follow-up: a regional audit of diabetes care in the UK

AIM

To determine changes in glycaemic control and lipids over time since the introduction of the Quality and Outcomes Framework.

METHODS

In adults with diabetes (Hampshire, UK), HbA1c and lipid measurements were retrieved from a regional National Health Service biochemical database in 2006 and 2013 and analysed using anova and logistic regression modelling.

RESULTS

In 2006, 8568 people with diabetes were identified. In 2013, 5815 had follow-up data, 1207 people were lost to follow-up and 1546 had died. At baseline, HbA1c concentrations were 62.1 ± 16.1, 64.7 ± 16.7 and 64.5 ± 17.6 mmol/mol for those with follow-up data, those lost to follow-up and those who died, respectively. The mean age was 60.2 ± 14.5, 57.6 ± 18.0 and 73.9 ± 10.5 years, respectively, for the three groups. Total cholesterol, HDL cholesterol and triglyceride concentrations were similar between groups. The mean HbA1c concentration for those with complete follow-up data was 62.1 ± 16.1 mmol/mol in 2006 and 61.7 ± 17.3 mmol/mol in 2013. Quality and Outcomes Framework targets for cholesterol (< 5 mmol/l) were achieved by 79% of people in 2006 and 83% in 2013 (P < 0.001). Baseline age and HbA1c were associated with death at follow-up: the odds ratio per year increase in baseline age was 1.10 (95% CI 1.09-1.10; P < 0.001) and per unit increase in HbA1c it was 1.02 (95% CI 1.02-1.03; P < 0.001).

CONCLUSIONS

Glycaemic control showed remarkable stability over 7 years of follow-up, despite increasing patient age and duration of diabetes. More patients achieved lipid targets in 2013 than in 2006. Although baseline HbA1c was a predictor of death at follow-up, baseline HbA1c differed little between survivors, non-survivors and those lost to follow-up.

General Life and Diabetes-Related Stressors in Early Adolescents With Type 1 Diabetes

INTRODUCTION

To examine general and diabetes-related stressors in early adolescents with type 1 diabetes (T1D).

METHOD

Data were from 205 participants (58% female; 33% minority; 11-14 years) enrolled in a clinical trial. Teens identified their top 3 stressors and responded to open-ended questions. A content analysis method was used to identify themes across stressor categories.

RESULTS

Eight-two percent of teens reported that school was a top stressor, followed by social life (49%) and diabetes (48%). We identified 5 themes of general life stressors (fitting in, having friends, balancing competing demands, living with family, and feeling pressure to do well) and 3 themes of diabetes-specific stressors (just having diabetes, dealing with emotions, and managing diabetes).

DISCUSSION

Though teens with T1D experienced stressors specific to T1D, they perceived stress related to normal adolescent growth and development more frequently. Teens with T1D may need psychosocial support that holistically addresses both typical developmental and diabetes-related stressors.

Different health behaviours and clinical factors associated with bone mineral density and bone turnover in premenopausal women with and without type 1 diabetes

BACKGROUND

Women with type 1 diabetes (T1DM) have an elevated fracture risk. We therefore compared the associations of health behaviours and clinical factors with bone mineral density (BMD) and bone remodelling between premenopausal women with and without T1DM to inform potential interventions.

METHODS

Participants included women with T1DM (n = 89) from the Wisconsin Diabetes Registry Study and age-matched and race-matched controls without diabetes (n = 76). Peripheral (heel and forearm) and central (hip and spine) BMD, markers of bone resorption and formation, bone cell signalling, glycaemic control, and kidney function were assessed. Health behaviours and medical history were self-reported.

RESULTS

In controls, but not in women with T1DM, older age was associated with lower bone resorption (p ≤ 0.006) and formation (p = 0.0007). Body mass index was positively associated with heel and forearm BMD in both controls and T1DM women (all p < 0.0001), but with hip and spine BMD only in controls (p ≤ 0.005). Worse glycaemic control during the previous 10 years, greater alcohol intake, history of smoking, and lack of physical activity were associated with poorer bone outcomes only in women with T1DM (all p ≤ 0.002), whereas use of hormonal contraceptives was related to low bone formation in both women with and without T1DM (all p ≤ 0.006). Diabetes duration, insulin dose, residual C-peptide, and kidney function were not associated with bone in T1DM.

CONCLUSIONS

Age and body mass index may not predict bone health in T1DM women. However, modifiable behaviours such as optimizing glycaemic control, limiting substance and hormonal contraceptive use, and increasing physical activity may improve bone health in T1DM women.

Longitudinal Analysis of Adiponectin through 20-Year Type 1 Diabetes Duration

Little information exists on the trajectory and determinants of adiponectin, a possible insulin sensitizer and marker for inflammation and endothelial function, across the duration of type 1 diabetes. The Wisconsin Diabetes Registry Study followed an incident cohort ≤ 30 years of age when diagnosed with type 1 diabetes during 1987-1992 up to 20-year duration. Adiponectin was concurrently and retrospectively (from samples frozen at -80 °C) measured for those participating in a 20-year exam (n = 304), during 2007-2011. Adiponectin levels were higher in females, declined through adolescence, and increased with age thereafter. Lower levels were associated with greater body weight and waist circumference and with higher insulin dose, especially at longer diabetes durations. Higher levels were associated with higher HbA1c and, at longer durations, with higher albumin-creatinine ratio. Adiponectin levels showed consistency within individuals that was not explained by these factors. We conclude that markers for insulin resistance are associated with lower adiponectin, and markers for potential microvascular complications are associated with higher adiponectin. The previously reported relationship with HbA1c remains largely unexplained. Additional individual specific factors likely also influence adiponectin level. The relationship between adiponectin and urinary protein excretion may enable identification of those predisposed to kidney disease earlier in type 1 diabetes.

The trajectory of IGF-1 across age and duration of type 1 diabetes

BACKGROUND

Individuals with type 1 diabetes may have low IGF-1, related to insulinopenia and insulin resistance. There are few longitudinal studies of IGF-1 levels to establish its pattern in type 1 diabetes with duration and age, and to examine whether IGF-1 tracks within individuals over time. We examine age and duration trends, and the relationship of IGF-1 to gender, glycaemic control, insulin level and other factors.

METHODS

Participants in the Wisconsin Diabetes Registry Study, an incident cohort study of type 1 diabetes diagnosed May 1987-April 1992, were followed for up to 18 years with IGF-1 samples up to age 45 for women and age 37 for men.

RESULTS

IGF-1 is lower with type 1 diabetes than in normative samples. Although, the pattern across age resembles that in normative samples with a peak in adolescence and slow decline after age 20, the adolescent peak is delayed for women with type 1 diabetes. There was low to moderate tracking of IGF-1 within an individual. Higher insulin dose was associated with higher IGF-1 as was puberty, and female gender. Adjusted for these factors, IGF-1 declined rapidly across early diabetes duration. Lower HbA1c was most strongly related to higher IGF-1 at Tanner stages 1 and 2.

CONCLUSIONS

IGF-1 is low in type 1 diabetes, with a delayed adolescent peak in women and is especially influenced by glycaemic control in early and pre-adolescence. High variability within an individual is likely a challenge in investigating associations between IGF-1 and long-term outcomes, and may explain contradictory findings.

Pediatric diabetes consortium T1D New Onset (NeOn) study: clinical outcomes during the first year following diagnosis

OBJECTIVE

There have been few prospective, multicenter studies investigating the natural history of type 1 diabetes (T1D) from the time of diagnosis. The objective of this report from the Pediatric Diabetes Consortium (PDC) T1D New Onset (NeOn) study was to assess the natural history and clinical outcomes in children during the first year after diagnosis of T1D.

RESEARCH DESIGN AND METHODS

Clinical measures from the first year following diagnosis were analyzed for 857 participants (mean age 9.1 yr, 51% female, 66% non-Hispanic White) not participating in an intervention study who had a HbA1c result at 12 months.

RESULTS

Mean HbA1c ± SD was 102 ± 25 mmol/mol (11.4 ± 2.3%) at diagnosis, 55 ± 12 mmol/mol (7.2 ± 1.1%) at 3 months, 56 ± 15 mmol/mol (7.3 ± 1.3%) at 6 months and 62 ± 16 mmol/mol (7.8 ± 1.5%) at 12 months from diagnosis. A severe hypoglycemic (SH) event occurred in 31 (4%) participants (44 events, 5.2 events per 100 person-years). Diabetic ketoacidosis (DKA) not including diagnosis occurred in 10 (1%) participants (13 events, 1.5 events per 100 person-years).

CONCLUSIONS

After onset of T1D, mean HbA1c reaches its nadir at 3-6 months with a gradual increase through 12 months. SH and DKA are uncommon but still occur during the first year with T1D. Data from large cohorts, such as the PDC T1D NeOn study, provide important insights into the course of T1D during the first year following diagnosis, which will help to inform the development of models to target future interventions.

Long-term outcome of insulin pump therapy in children with type 1 diabetes assessed in a large population-based case-control study

AIMS/HYPOTHESIS

We determined the impact of insulin pump therapy on long-term glycaemic control, BMI, rate of severe hypoglycaemia and diabetic ketoacidosis (DKA) in children.

METHODS

Patients on pump therapy at a single paediatric tertiary hospital were matched to patients treated by injections on the basis of age, duration of diabetes and HbA1c at the time of pump start. HbA1c, anthropometric data, episodes of severe hypoglycaemia and rates of hospitalisation for DKA were collected prospectively.

RESULTS

A total of 345 patients on pump therapy were matched to controls on injections. The mean age, duration of diabetes at pump start and length of follow-up were 11.4 (± 3.5), 4.1 (± 3.0) and 3.5 (± 2.5) years, respectively. The mean HbA1c reduction in the pump cohort was 0.6% (6.6 mmol/mol). This improved HbA1c remained significant throughout the 7 years of follow-up. Pump therapy reduced severe hypoglycaemia from 14.7 to 7.2 events per 100 patient-years (p < 0.001). In contrast, severe hypoglycaemia increased in the non-pump cohort over the same period from 6.8 to 10.2 events per 100 patient-years. The rate of hospitalisation for DKA was lower in the pump cohort (2.3 vs 4.7 per 100 patient-years, p = 0.003) over the 1,160 patient-years of follow-up.

CONCLUSIONS/INTERPRETATION

This is the longest and largest study of insulin pump use in children and demonstrates that pump therapy provides a sustained improvement in glycaemic control, and reductions of severe hypoglycaemia and hospitalisation for DKA compared with a matched cohort using injections.

Assessing progress in retinopathy outcomes in type 1 diabetes: comparing findings from the Wisconsin Diabetes Registry Study and the Wisconsin Epidemiologic Study of Diabetic Retinopathy

OBJECTIVE

The Wisconsin Diabetes Registry Study (WDRS) cohort consisted of patients diagnosed with type 1 diabetes in the same geographic region as, but 8-34 years later than the Wisconsin Epidemiologic Study of Diabetic Retinopathy (WESDR) cohort, providing a unique opportunity to assess changes in complications. We estimated the current prevalence and severity of diabetic retinopathy at 20 years of diabetes duration, compared these between eras, and evaluated the influence of diabetes management.

RESEARCH DESIGN AND METHODS

Twenty-year examinations, including fundus photographs, were completed on 305 WDRS subjects during 2007-2011. A subgroup of the WESDR cohort participated in one of four study visits during 1980-1996, at similar diabetes duration (n = 583). Adjusted ordinal logistic regression with three retinopathy severity categories was used to estimate odds ratios (ORs) of more severe retinopathy with diagnosis during an earlier era.

RESULTS

Mean hemoglobin A(1c) (HbA(1c)) was lower in WDRS than in WESDR (8.0% vs. 9.3% [P < 0.001], and 93.4% vs. 21.3% [P < 0.001]) used ≥3 daily insulin injections or an insulin pump. In WDRS, 18% had vision-threatening levels of retinopathy vs. 43% in WESDR. The adjusted OR of more severe retinopathy in the earlier era (OR 3.0 [95% CI 2.2-4.0]) was reduced by including 20-year HbA(1c) in the model (OR 2.2 [1.6-3.0]).

CONCLUSIONS

Retinopathy severity at a diabetes duration of 20 years is lower in the more recent era of type 1 diabetes. Updated projections should be used when informing newly diagnosed individuals of prognosis and for health care cost assessments. Current glycemic control explained a limited amount of the difference.

An automated communication system in a contact registry for persons with rare diseases: scalable tools for identifying and recruiting clinical research participants

OBJECTIVES

Strategies for study recruitment are useful in clinical research network settings. We describe a registry of individuals who have self-identified with one of a multiplicity of rare diseases, and who express a willingness to be contacted regarding possible enrollment in clinical research studies. We evaluate this registry and supporting tools in terms of registry enrollment and impact on participation rates in advertised clinical research studies.

METHODS

A web-based automated system generates periodic and customized communications to notify registrants of relevant studies in the NIH Rare Diseases Clinical Research Network (RDCRN). The majority of these communications are sent by email. We compare the characteristics of those enrolled in the registry to the characteristics of participants enrolled in sampled RDCRN studies in order to estimate the impact of the registry on study participation in the network.

RESULTS

The registry currently contains over 4000 registrants, representing 40 rare diseases. Estimates of study participation range from 6-27% for all enrollees. Study participation rates for some disease areas are over 40% when considering only contact registry enrollees who live within 100 mi of a clinical research study site.

CONCLUSIONS

Automated notifications can facilitate consistent, customized, and timely communication of relevant protocol information to potential research subjects. Our registry and supporting communication tools demonstrate a significant positive impact on study participation rates in our network. The use of the internet and automated notifications make the system scalable to support many protocols and registrants.

Adolescent use of insulin and patient-controlled analgesia pump technology: a 10-year Food and Drug Administration retrospective study of adverse events

OBJECTIVES

From January 1, 2005, through December 31, 2005, the Food and Drug Administration received 5 adolescent death reports associated with the use of insulin pumps, raising concerns about use of this device in this age group. To understand better the types of infusion pump-related problems in adolescents, we performed a comprehensive evaluation of insulin and patient-controlled analgesic pump-related adverse events reported for adolescents that were received by the Food and Drug Administration from 1996 to 2005.

METHODS

A search for medical device adverse event reports from January 1, 1996 through December 31, 2005, involving insulin pumps or patient-controlled analgesic pumps used by patients who were aged 12 to 21 years was conducted in the Food and Drug Administration's Manufacturer and User Facility Device Experience Database. Reports were reviewed for demographic characteristics, type of adverse event, and patient morbidity, and potential contributory factors were classified from narratives in the reports.

RESULTS

A total of 1674 reports were identified: 1594 for insulin pumps and 53 for patient-controlled analgesic pumps. In reports of insulin pump events, there were 13 reported deaths, 2 reports that indicated possible suicide attempts, and several additional reports indicating severe hypoglycemic or hyperglycemic events that seemed to be device-related. A total of 102 (6.4%) insulin-pump reports highlighted factors that may have contributed to the adverse event, including problems associated with compliance, education, sports-related activities, and dropping or damaging the pump. Eighty-two percent of cases involving the insulin pump resulted in hospitalization. Half of the reports involving patient-controlled analgesic pumps indicated that the patient received an excess of medication; tampering and noncompliance were evident in some cases.

CONCLUSIONS

Adolescents are a special population who deserve careful consideration of risk and benefit for use of device technology. Studies need to further identify safety problems in this age group.

Hospital admission patterns subsequent to diagnosis of type 1 diabetes in children : a systematic review

Background

Patients with type 1 diabetes are known to have a higher hospital admission rate than the underlying population and may also be admitted for procedures that would normally be carried out on a day surgery basis for non-diabetics. Emergency admission rates have sometimes been used as indicators of quality of diabetes care.

In preparation for a study of hospital admissions, a systematic review was carried out on hospital admissions for children diagnosed with type 1 diabetes, whilst under the age of 15. The main thrust of this review was to ascertain where there were gaps in the literature for studies investigating post-diagnosis hospitalisations, rather than to try to draw conclusions from the disparate data sets.

Methods

A systematic search of the electronic databases PubMed, Cochrane LibrarMEDLINE and EMBASE was conducted for the period 1986 to 2006, to identify publications relating to hospital admissions subsequent to the diagnosis of type 1 diabetes under the age of 15.

Results

Thirty-two publications met all inclusion criteria, 16 in Northern America, 11 in Europe and 5 in Australasia. Most of the studies selected were focussed on diabetic ketoacidosis (DKA) or diabetes-related hospital admissions and only four studies included data on all admissions. Admission rates with DKA as primary diagnosis varied widely between 0.01 to 0.18 per patient-year as did those for other diabetes-related co-morbidity ranging from 0.05 to 0.38 per patient year, making it difficult to interpret data from different study designs. However, people with Type 1 diabetes are three times more likely to be hospitalised than the non-diabetic populations and stay in hospital twice as long.

Conclusion

Few studies report on all admissions to hospital in patients diagnosed with type 1 diabetes whilst under the age of 15 years. Health care costs for type 1 patients are higher than those for the general population and information on associated patterns of hospitalisation might help to target interventions to reduce the cost of hospital admissions.

Increases in central aortic impedance precede alterations in arterial stiffness measures in type 1 diabetes

OBJECTIVE

Increased pulse pressure has been associated with increased cardiovascular risk in individuals with diabetes. Changes in central aortic properties can increase central pulse pressure and may adversely affect microvascular perfusion and cardiac performance. This study was performed to define early changes in central arterial properties in a group of young individuals with type 1 diabetes.

RESEARCH AND DESIGN METHODS

Seventeen individuals with type 1 diabetes and their nondiabetic control subjects who were participating in the Cardio-Diab Study had arterial stiffness and pulsatile hemodynamics measured with calibrated tonometry and pulsed Doppler. Aortic characteristic impedance (Z(c)) was calculated from the ratio of change in carotid pressure and aortic flow in early systole. Pulse wave velocity (PWV) was assessed from tonometry and body surface measurements.

RESULTS

Duration of type 1 diabetes was 15.3 +/- 0.7 (mean +/- SD) years. In type 1 diabetic subjects, central pulse pressure was elevated (45 +/- 11 vs. 36 +/- 10 mmHg in control subjects, P = 0.02), as was peripheral pulse pressure (54 +/- 13 vs. 43 +/- 10 mmHg, P = 0.002). Z(c) was elevated in type 1 diabetes (179 +/- 57 vs. 136 +/- 42 dynes x s/cm5 in control subjects, P = 0.004), whereas PWV was not different (5.9 +/- 0.9 vs. 5.9 +/- 0.7 m/s in type 1 diabetic vs. control subjects, respectively; NS). There was a moderate correlation between Z(c) and urinary albumin excretion (coefficient 0.39, P = 0.02).

CONCLUSIONS

Z(c) appears to be increased early in type 1 diabetes, before elevation of PWV and is associated with higher pulse pressure, which may contribute to renal microvascular damage in diabetes.

Predicting metabolic control in the first 5 yr after diagnosis for youths with type 1 diabetes: the role of ethnicity and family structure

The primary purpose of this study was to determine if there were differences in trajectories of metabolic control between African American and White youth with type 1 diabetes in the first 5 yr after diagnosis. A secondary purpose was to investigate other sociodemographic variables that often covary with race/ethnicity such as number of parents in the home and family income to determine if they predicted trajectories of metabolic control in youth with diabetes over and above the effects of ethnicity. A convenience sample of 71 youth was recruited. Multilevel modeling was used to estimate the population trajectory and to investigate the contribution of other variables. Differences in metabolic control between African American and White youth began shortly after diagnosis and continued to accelerate well beyond the point of diagnosis. However, subsequent analysis showed that deterioration in metabolic control could equally well be explained by living in a single-parent household. At 24 months postdiagnosis, the metabolic control in youth from single-parent families worsened almost three times as fast as that in youth from two-parent families (0.11 vs. 0.04%/month). The difference in hemoglobin A1c level at 24 months was 1.34% (p = .007). Neither family income nor clinical variables such as child's age, Tanner stage, or body mass index was significant predictor of metabolic control. Diabetes care providers should consider developing targeted interventions such as parent social support resources or school-based youth monitoring programs for youth in single-parent families.

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

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

The association of increased total glycosylated hemoglobin levels with delayed age at menarche in young women with type 1 diabetes

CONTEXT

Delayed menarche is associated with subsequent reproductive and skeletal complications. Previous research has found delayed growth and pubertal maturation with type 1 diabetes and poor glycemic control. The effect of diabetes management on menarche is important to clarify, because tighter control might prevent these complications.

OBJECTIVE

The objective of this study was to investigate age at menarche in young women with type 1 diabetes and examine the effect of diabetes management [e.g. total glycosylated hemoglobin (GHb) level, number of blood glucose checks, insulin therapy intensity, and insulin dose] on age at menarche in those diagnosed before menarche.

DESIGN

The Wisconsin Diabetes Registry Project is a follow-up study of a type 1 diabetes population-based incident cohort initially enrolled between 1987 and 1992.

SETTING

This study was performed in 28 counties in south-central Wisconsin.

PATIENTS OR OTHER PARTICIPANTS

The study participants were recruited through referrals, self-report, and hospital/clinic ascertainment. Individuals with newly diagnosed type 1 diabetes, less than 30 yr old, were invited to participate. Of 288 young women enrolled, 188 reported menarche by 2002; 105 were diagnosed before menarche.

INTERVENTIONS

There were no interventions.

MAIN OUTCOME MEASURE

The main outcome measure was age at menarche.

RESULTS

Mean age at menarche was 12.78 yr, compared with 12.54 yr in the United States (P = 0.01). Ages at menarche and diagnosis were not associated. For those diagnosed before menarche, age at menarche was delayed 1.3 months with each 1% increase in mean total GHb level in the 3 yr before menarche.

CONCLUSIONS

Age at menarche was moderately delayed in young women with type 1 diabetes. Delayed menarche could potentially be minimized with improved GHb levels.

Nationwide cross-sectional survey of 3560 children and adolescents with diabetes in Italy

Clinical characteristics and metabolic control in a large cohort of children with Type 1 diabetes (T1DM) were evaluated. Fifty-three Italian centers for childhood diabetes collected blood samples and clinical records from 3560 consecutive eligible patients aged 1.6-17.10 yr with disease duration >12 months. HbA1c determinations were centralized in a Diabetes Control and Complications Trial-controlled laboratory. HbA1c grand mean was 8.87 +/- 1.77%. Thirty-two percent of the patients had HbA1c values <8.0%. Puberty and disease duration were the main determinants of increase in HbA1c levels (<0.001). HbA1c values were inversely correlated to the frequency of blood glucose monitoring (p<0.001). Among the total population, 53.7% of the patients had 4 or more injections per day, 37.8% three injections, 7.4% < or =2 injections and only 1.1% was on pumps. Daily number of injections increased with age (p<0.001). Hypoglycemia episodes were reported in 17.6% patient-years and diabetic ketoacidosis (DKA) in 1.0% of children, more frequently in those with HbA1c >8.8% (p<0.02). Two thirds of Italian children with T1DM have HbA1c>8% despite regionalized centers, multidisciplinary team approach, free access to appropriate diabetes care, education, frequent blood glucose monitoring and multiple insulin injections.

Coping with everyday stress and links to medical and psychosocial adaptation in diabetic adolescents

PURPOSE

To study coping with everyday stressors in a longitudinal sample of 98 adolescents with insulin-dependent mellitus (type 1) diabetes.

METHODS

The adolescents with type 1 diabetes were classified into three homogeneous groups of metabolic control by latent class analysis, based on annual tests of hemoglobin A1 values. Questionnaires assessing frequent minor stressors as well as ways of coping with these stressors were given annually over the course of 4 years. Latent class analysis revealed three distinctive groups of metabolic control over time. Adolescents who exhibited continuously poor, satisfactory, and good metabolic control. Eighty percent of the adolescents stayed in the group assigned to them over the 4-year period.

RESULTS

Adolescents with stable good metabolic control were characterized by lower levels of minor stressors that decreased over time, but those with stable satisfactory and poor metabolic control experienced continuously higher stress levels. Adolescents with stably good metabolic control also employed less avoidant coping in dealing with minor stressors, compared with the two other groups.

CONCLUSIONS

Because of the danger of long-term complications, it is important to discriminate among different groups of metabolic control over time. Further, the impact of non-illness-related minor stressors on metabolic control should be considered for prevention purposes.

Bias adjustment in analysing longitudinal data with informative missingness

The recent biostatistical literature contains a number of methods for handling the bias caused by 'informative censoring', which refers to drop-out from a longitudinal study after a number of visits scheduled at predetermined intervals. The same or related methods can be extended to situations where the missing pattern is intermittent. The pattern of missingness is often assumed to be related to the outcome through random effects which represent unmeasured individual characteristics such as health awareness. To date there is only limited experience with applying the methods for informative censoring in practice, mostly because of complicated modelling and difficult computations. In this paper, we propose an estimation method based on grouping the data. The proposed estimator is asymptotically unbiased in various situations under informative missingness. Several existing methods are reviewed and compared in simulation studies. We apply the methods to data from the Wisconsin Diabetes Registry Project, a longitudinal study tracking glycaemic control and acute and chronic complications from the diagnosis of type I diabetes.

Risk factors for frequent and severe hypoglycemia in type 1 diabetes

OBJECTIVE

To determine the risk of frequent and severe hypoglycemia and the associated demographic and clinical risk factors.

RESEARCH DESIGN AND METHODS

Demographic and diabetes self-management factors were measured in 415 subjects followed prospectively for 4-6.5 years of type 1 diabetes duration as participants in a population-based incident cohort. Blood samples were collected up to three times yearly to test glycosylated hemoglobin (GHb) levels. Reports of frequent (2-4 times/week) and severe (lost consciousness) hypoglycemia as well as other diabetes self-management data were collected by questionnaires.

RESULTS

Frequent hypoglycemia was common (33 and 35% of participants reported this on the 4- and 6.5-year questionnaires, respectively), whereas severe hypoglycemia occurred much less often. Better glycemic control (odds ratio [OR] 1.3 per 2% decrease in GHb, 95% CI 1.1-1.5) and more frequent self-monitored blood glucose (1.5 per blood glucose check, 1.3-1.7) were independently related to frequent hypoglycemia. The association of frequent hypoglycemia with intensive insulin therapy increased with age. Better glycemic control (1.5 per 2% decrease in GHb, 1.2-2.0) and older age were related to severe hypoglycemic reactions. No sociodemographic factors other than age increased the risk of hypoglycemia.

CONCLUSIONS

Frequent hypoglycemia was common in a population representing the full range of glycemic control in the community. Intensive insulin management and blood glucose monitoring independently predicted frequent but not severe hypoglycemia. This information may be useful for updating patients such that minor changes in diabetes management might decrease the daily burden of this condition while maintaining intensive insulin therapy.

Intra-individual variability and longitudinal changes in glycaemic control in patients with Type 1 diabetes mellitus

AIMS

Patients with Type 1 diabetes mellitus (DM) appear to have remarkably stable HbA1c levels, regardless of the need for improvement. The purpose of the present study was therefore to study predictors of intra-individual variability of the HbA1c level together with changes in HbA1c over time.

METHODS

Hospital records of patients with Type 1 DM seen at our diabetes clinic from February 1992 to May 1997 were reviewed for HbA1c measurements and clinical data. In the main study, 214 patients who had been on insulin for more than 1 year, and in a sub-study, 14 patients newly started on insulin, were included.

RESULTS

The coefficient of variation (CV) of the intra-individual HbA1c measurements, after at least 1 year of insulin, was 8.8 +/- 3.7% (mean +/- SD). There was a positive association between the CV and the HbA1c measurement at inclusion in the study (P < 0.05), and also a negative association between the CV and age (P < 0.05). Fifty per cent of the patients had a difference between first and last HbA1c below 1%, and 83.6% had a difference below 2%. In the sub-study, there was a positive association between the mean HbA1c value the first year on insulin (excluding the first 3 months) and the last HbA1c measurement (P < 0.01).

CONCLUSIONS

The HbA1c levels in individual patients remain remarkably stable over time. Furthermore, the HbA1c level shortly after starting insulin is a predictor of future glycaemic control.

Social support and personal models of diabetesin relation to self-care and well-being inadolescents with type I diabetes mellitus

This study set out to examine whether peer support and illness representation mediates the link between family support, self-management and well-being. Seventy-four participants (12-18-years-old) with type I diabetes mellitus completed questionnaires assessing their self-management, depression, anxiety, perceived social support and personal models of diabetes. Perceived impact of diabetes, but not perceived seriousness, and peer support were significant predictors of depression. Family support was a significant predictor of all self-management measures. However, for dietary self-management this relationship was partially mediated by the perceived efficacy of treatment to control diabetes, but not efficacy of treatment to prevent complications.