Cardiac Autonomic Nerve Dysfunction Predicts Incident Retinopathy and Early Kidney Dysfunction in Adolescents With Type 1 Diabetes.

OBJECTIVE: Cardiac autonomic neuropathy (CAN) may contribute to vascular complications in diabetes. We hypothesized that adolescents with CAN are at greater risk of diabetic retinopathy and early kidney dysfunction. RESEARCH DESIGN AND METHODS: In this prospective longitudinal study of 725 adolescents with type 1 diabetes without retinopathy and albuminuria at baseline, early CAN was defined as one or more abnormalities in seven heart rate tests derived from a 10-min electrocardiogram. Retinopathy was defined as the presence of one or more microaneurysms, early kidney dysfunction as an albumin excretion rate (AER) >7.5 µg/min, and albuminuria as an AER >20 µg/min. Multivariable generalized estimating equations were used to examine the association between CAN and retinopathy or early kidney dysfunction. Cox proportional hazards regression analysis was used to assess cumulative risks of incident retinopathy and albuminuria. RESULTS: At baseline, the mean age of the sample was 13.6 ± 2.6 years, 52% were male, and mean diabetes duration was 6.1 ± 3.3 years. Over a median follow-up of 3.8 (interquartile range 2.2-7.5) years, the complication rate 27% for retinopathy, 16% for early kidney dysfunction, and 3% for albuminuria. The mean study HbA1c was 72.3 ± 16 mmol/mmol (8.6 ± 1.4%). CAN predicted incident retinopathy (odds ratio 2.0 [95% CI 1.4, 2.9]) and early kidney dysfunction (1.4 [1.0, 2.0]) after adjusting for HbA1c and diabetes duration. CAN also predicted retinopathy (hazard ratio 1.57 [95% CI 1.09, 2.26]) and albuminuria (2.30 [1.05, 5.04]) independently of HbA1c. CONCLUSIONS: CAN predicted incident retinopathy and kidney dysfunction in adolescents with type 1 diabetes, likely reflecting autonomic microvascular dysregulation contributing to complications. Therefore, screening and interventions to reduce CAN may influence the risk of complications.

Optimal Frequency of Retinopathy Screening in Adolescents With Type 1 Diabetes: Markov Modeling Approach Based on 30 Years of Data.

OBJECTIVE: Current guidelines recommend biennial diabetic retinopathy (DR) screening commencing at the age of 11 years and after 2-5 years' duration of type 1 diabetes. Growing evidence suggests less frequent screening may be feasible. RESEARCH DESIGN AND METHODS: Prospective data were collected from 2,063 youth with type 1 diabetes who were screened two or more times between 1990 and 2019. Baseline (mean ± SD) age was 13.3 ± 1.8 years, HbA1c was 8.6 ± 1.3% (70.1 ± 14.7 mmol/mol), diabetes duration was 5.6 ± 2.8 years, and follow-up time was 4.8 ± 2.8 years. DR was manually graded from 7-field retinal photographs using the Early Treatment Diabetic Retinopathy Study (ETDRS) scale. Markov chain was used to calculate probabilities of DR change over time and hazard ratio (HR) of DR stage transition. RESULTS: The incidence of moderate nonproliferative DR (MNPDR) or worse was 8.6 per 1,000 patient-years. Probabilities of transition to this state after a 3-year interval were from no DR, 1.3%; from minimal DR, 5.1%; and from mild DR, 22.2%, respectively. HRs (95% CIs) for transition per 1% current HbA1c increase were 1.23 (1.16-1.31) from no DR to minimal NPDR, 1.12 (1.03-1.23) from minimal to mild NPDR, and 1.28 (1.13-1.46) from mild to MNPDR or worse. HbA1c alone explained 27% of the transitions between no retinopathy and MNPDR or worse. The addition of diabetes duration into the model increased this value to 31% (P = 0.03). Risk was also increased by female sex and higher attained age. CONCLUSIONS: These results support less frequent DR screening in youth with type 1 diabetes without DR and short duration. Although DR progression to advanced stages is generally slow, higher HbA1c greatly accelerates it.

Higher frequency of cardiovascular autonomic neuropathy in youth with type 2 compared to type 1 diabetes: Role of cardiometabolic risk factors.

OBJECTIVE: Cardiovascular autonomic neuropathy (CAN) is an overlooked but common and serious diabetes complication. We examined CAN in youth with diabetes and associations with cardiovascular risk factors. RESEARCH DESIGN AND METHODS: This was a prospective cohort of youth aged <20 years with type 2 or type 1 diabetes (n = 66/1153, median age 15.4/16.5 years, duration 1.7/8.0 years), assessed between 2009 and 2020. CAN was defined as ≥2 abnormal heart rate variability measures across time, geometric, and frequency domains. Obesity was defined as BMI ≥ 95th percentile and severe obesity as ≥120% of 95th percentile. Multivariable generalized estimating equations (GEE) were used to examine putative risk factors for CAN, including diabetes type, obesity, and HbA1c . RESULTS: At most recent assessment, youth with type 2 versus type 1 diabetes had median: HbA1 c 7.1% (54 mmol/mol) versus 8.7% (72 mmol/mol) and BMI SDS (2.0 vs. 0.7); frequency of CAN (47% vs. 27%), peripheral nerve abnormality (47% vs. 25%), hypertension (29% vs. 12%), albuminuria (21% vs. 3%), and severe obesity (35% vs. 2%). In multivariable GEE, CAN was associated with type 2 diabetes: Odds Ratio 2.53, 95% CI 1.46, 4.38, p = 0.001, higher BMI SDS: 1.49, 95% CI 1.29, 1.73, p < 0.0001, and obesity: 2.09, 95% CI 1.57, 2.78, p < 0.0001. CONCLUSIONS: Youth with type 2 diabetes have a higher frequency of CAN, peripheral nerve abnormality, hypertension, albuminuria and severe obesity despite shorter diabetes duration and younger age. Our findings highlight the importance of targeting modifiable risk factors to prevent cardiovascular disease in youth with diabetes.

Baseline extended zone retinal vascular calibres associate with sensory nerve abnormalities in adolescents with type 1 diabetes: A prospective longitudinal study.

OBJECTIVE: The relationship between retinal vascular calibres (RVCs) and diabetic neuropathy is unclear. We investigated associations between RVCs and sensory nerve abnormality in adolescents with type 1 diabetes. RESEARCH DESIGN AND METHODS: In a prospective longitudinal study of 889 adolescents with type 1 diabetes with baseline mean (±SD) age 14.1 ± 1.5 years and HbA1c IFCC 69.4 ± 14.1 mmol/mol (8.6 ± 1.3%), RVCs were assessed from baseline retinal photographs: 'central zone' calibres, summarized as central retinal arteriolar (CRAE) and venular equivalents (CRVE) and 'extended zone' calibres: mean width of arterioles (MWa) and venules (MWv). Sensory nerve abnormality was defined as at least one abnormal sensory quantitative testing from two thermal and two vibration threshold tests measured at foot every 1-2 years. Associations between baseline RVC and sensory nerve function were examined using generalized estimating equations and cumulative risk by Cox regression analyses. RESULTS: During a median study follow-up of 6.2 [IQR 3.7-10.4] years, sensory nerve abnormality was found in 27% of adolescents. Narrower extended zone calibre quartiles but not CRAE or CRVE quartiles were independently associated with sensory nerve abnormality: MWa (Q1 vs. Q2-4: OR 1.35 (95% CI 1.02, 1.61) and MWv (Q1 vs. Q2-4: 1.31 (1.03, 1.7)), after adjusting for HbA1c , duration and blood pressure. Similarly, in Cox regression, the narrowest quartiles were associated with sensory nerve abnormality: MWa hazard ratio (HR) 1.5 (1.3, 1.8) and MWv 1.6 (1.4, 1.9). CONCLUSIONS: Narrower extended zone retinal calibres were associated with sensory nerve abnormality in adolescents with type 1 diabetes and may present useful biomarkers to understand the pathophysiology of neuropathy.

Extended-Zone Retinal Vascular Caliber and Risk of Diabetic Retinopathy in Adolescents with Type 1 Diabetes.

PURPOSE: Retinal vascular caliber has been linked to diabetic retinopathy (DR). Newer imaging technologies allow analysis of retinal vascular caliber beyond the standard areas surrounding the optic disc. We investigated the vascular caliber in extended zones in prediction of DR in adolescents with type 1 diabetes. DESIGN: Prospective, longitudinal study. PARTICIPANTS: Adolescents (n = 904) who attended the diabetes complications assessment service at the Children's Hospital at Westmead. METHODS: Retinal caliber was assessed from baseline retinal photographs with a semiautomated computer software Singapore I Vessel Assessment: standard zone retinal vessel calibers were summarized as central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE), and extended-zone vessels (>2 disc diameters from the optic disc margin) were summarized as mean width of arterioles (MWa) and mean width of venules (MWv). MAIN OUTCOME MEASURES: Retinal vessel calibers at baseline (upper 3 quartiles vs. lowest quartiles [Q2-4 vs. Q1]) and moderate DR (stage 3 or more) were analyzed using multivariate generalized estimating equations, with results expressed as odds ratios (OR) and 95% confidence intervals (CIs). RESULTS: Among the 904 participants, baseline mean age ± standard deviation was 14.0 ± 1.5 years, hemoglobin A1C (HbA1C) level was 8.5 ± 1.3%, and median diabetes duration 4.6 years. After a median 3-year follow-up, 15% of adolescents demonstrated moderate DR. Wider extended-zone retinal arteriolar caliber (MWa; OR, 3.6 [95% CI, 2.06-6.1], comparing Q2-4 vs. Q1) and venular caliber (MWv; OR, 4.2 [95% CI, 2.2-7.5]) predicted moderate DR after adjusting for HbA1C and blood pressure. Standard zone CRAE and CRVE were not associated with moderate DR. CONCLUSIONS: Extended-zone retinal vessel caliber predicts moderate DR in adolescents with type 1 diabetes.