Biomedical subjects

Stephen Hing

Publications and source records attributed to Stephen Hing.

7 recordsLinked to original sources

PubMed2006

Retinal vascular caliber and risk of retinopathy in young patients with type 1 diabetes.

OBJECTIVE: To examine the relationship between retinal vascular caliber and incident retinopathy in children and adolescents with type 1 diabetes mellitus. DESIGN: Hospital-based case-control study with prospective outcomes. PARTICIPANTS: Cases and controls were selected from a cohort of children and adolescents 12 to 20 years old with type 1 diabetes followed up at a tertiary diabetes clinic. Cases were patients who developed incident diabetic retinopathy (n = 166) after at least 1 year of follow-up (> or =2 clinic visits), and controls were patients who had not developed retinopathy (n = 165) after > or =2 years of follow-up (> or =3 clinic visits). Baseline retinal photographs of cases and controls were digitized, and retinal vascular calibers were measured using a computer-assisted program by a grader masked to case-control status. These measurements were combined into summary indices reflecting the average arteriolar and venular calibers. MAIN OUTCOME MEASURE: Development of diabetic retinopathy. RESULTS: Incident retinopathy cases had retinal arteriolar calibers (mean +/- standard deviation [SD], 206.5+/-18.4 microm) significantly larger than those of controls (200.2+/-16.5 microm) (P = 0.004) but similar retinal venular calibers (329.1+/-14.7 microm in cases vs. 326.4+/-15.1 microm in controls, P = 0.312). After adjusting for age, gender, diabetes duration, glycated hemoglobin levels, blood pressure, body mass index, and pubertal stage, larger arteriolar caliber was predictive of risk of diabetic retinopathy (odds ratio, 1.44 per SD increase in arteriolar caliber; 95% confidence interval, 1.11-1.86). CONCLUSION: Larger retinal arteriolar caliber predicts incident retinopathy in children and adolescents with type 1 diabetes, independent of conventional risk factors for retinopathy. Measurement of retinal vascular caliber may provide prognostic information regarding the subsequent risk of diabetic retinopathy.

Adolescent↗

PubMed2006

Intermittent exotropia: comparison of treatments.

PURPOSE: To identify the best treatment option for intermittent exotropia. METHODS: A retrospective analysis of the progress of 150 treated intermittent exotropia patients was performed. Treatment forms considered are: (i) surgery combined with orthoptic/occlusion therapy; (ii) surgery; (iii) orthoptic/occlusion therapy; and (iv) observation. Pearson's chi(2)-analysis of association of therapy form with success was performed. Reduction of exodeviation in prism dioptres between groups and subgroups were compared at 6 months, 1, 2 and 5 years follow up and the "within group" variations were compared. Exodeviation reduction in prism dioptres per millimetre of horizontal rectus surgery performed in the "surgery with orthoptic/occlusion therapy" and "surgery only" groups were compared. RESULTS: Chi(2)-analysis revealed a significantly highest (P < 0.001) association with success in the "surgery with orthoptic/occlusion therapy" group at follow up. ANOVA analysis revealed that surgery with orthoptic/occlusion therapy resulted significantly (P < 0.001) in the highest reduction of exodeviation as compared with the other three treatment modalities at each follow up. Reduction of exodeviation in prism dioptres per millimetre of horizontal rectus surgery performed was significantly higher (P < 0.05) in the surgery with orthoptic/occlusion therapy group as compared with surgery only at all follow ups. Chi(2)-test revealed no significant association of success with the magnitude of initial exodeviation (P > 0.05). CONCLUSION: Surgery with preoperative orthoptic/occlusion therapy had the highest success rates. Surgery with orthoptic/occlusion therapy was more effective in reducing exodeviation (prism dioptres per millimetre of horizontal rectus surgery), compared with surgery only.

Child↗

PubMed2006

Prevalence of diabetes complications in adolescents with type 2 compared with type 1 diabetes.

OBJECTIVE: To compare the prevalence of diabetes complications and their risk factors in youth with type 1 versus type 2 diabetes. RESEARCH DESIGN AND METHODS: We performed a comparative clinic-based study of 1,433 patients with type 1 diabetes and 68 patients with type 2 diabetes aged <18 years from New South Wales, Australia. Retinopathy was assessed by seven-field stereoscopic retinal photography; albumin excretion rate from three consecutive, timed, overnight urine collections; peripheral neuropathy by thermal and vibration threshold; and autonomic neuropathy by pupillometry. HbA(1c) (A1C) and lipids were measured in all patients and C-peptide in patients with type 2 diabetes. RESULTS: In patients with type 1 versus type 2 diabetes, median (interquartile range) age was 15.7 years (13.9-17.0) and 15.3 years (13.6-16.4), respectively (P = 0.2), whereas median diabetes duration was 6.8 years (4.7-9.6) and 1.3 years (0.6-3.1), respectively (P < 0.0001). Retinopathy was significantly more common in patients with type 1 diabetes (20 vs. 4%, P = 0.04), while microalbuminuria and hypertension were significantly less common (6 and 16% in type 1 diabetes vs. 28 and 36% in type 2 diabetes). Rates of peripheral and autonomic neuropathy were similar (27 and 61% in type 1 diabetes vs. 21 and 57% in type 2 diabetes). In multivariate analyses, microalbuminuria was significantly associated with older age (odds ratio 1.3 [95% CI 1.2-1.5], P < 0.001) and systolic hypertension (3.63 [2.0-6.3], P < 0.001) in type 1 diabetes, while only higher A1C (1.7 [1.3-2.9], P = 0.002) was significant in patients with type 2 diabetes. CONCLUSIONS: Youth with type 2 diabetes have significantly higher rates of microalbuminuria and hypertension than their peers with type 1 diabetes, despite shorter diabetes duration and lower A1C. The results of this study support recommendations for early complications screening and aggressive targeting of glycemic control in patients with type 2 diabetes.

Adolescent↗

PubMed2005

The case for biennial retinopathy screening in children and adolescents.

OBJECTIVE: Current guidelines recommend annual retinopathy screening 2 years after onset (for pubertal-onset type 1 diabetes) and after 5 years (or age 11, whichever is earlier) for prepubertal onset. Our aim was to describe the natural history of retinopathy and to explore optimal retinal screening intervals for children and adolescents (aged <20 years) screened according to these guidelines. RESEARCH DESIGN AND METHODS: More than 1,000 children and adolescents, followed longitudinally, were screened for retinopathy using seven-field stereoscopic fundus photography through dilated pupils. Of these, 668 had baseline and follow-up retinal screening. Using generalized estimating equations, we compared the risk of retinopathy with baselines at yearly intervals, in older and younger groups, in higher risk groups (diabetes duration >10 years or HbA(1c) >10% at any screening), and after stratification </=10 and <10 years in duration. RESULTS: After 1 year, retinopathy did not increase significantly in the older group (n = 618, median HbA(1c) 8.7%, range 8.0-9.5), younger group (n = 50, median HbA(1c) 8.5%, range 8.0-9.2), or the higher-risk groups. Retinopathy increased significantly after 2 years in the older group (P = 0.003) but not until 6 years in the younger group (P = 0.01). In the group with HbA(1c) >10% recorded at any visit, retinopathy increased significantly after 2 years (P = 0.001) but not until 3 years in the group whose HbA(1c) was always </=10% (P = 0.003). After the second eye assessment, retinopathy did not increase significantly until 3 and 6 years later in the older and younger groups, respectively (P = 0.028 and 0.014). CONCLUSIONS: These results suggest that adolescents (in reasonable metabolic control) could safely be screened every 2 years rather than the currently recommended 1-year interval. In younger children, the next screening interval could be >2 years later. Individuals with especially poor control, duration >10 years, or significant retinopathy should be screened more frequently.

Adolescent↗

PubMed2005

Discordant trends in microvascular complications in adolescents with type 1 diabetes from 1990 to 2002.

OBJECTIVE: Since the Diabetes Control and Complications Trial, diabetes management goals have changed. The aims of the present study were to assess complication rates, including nerve abnormalities, in adolescents from 1990 to 2002 and to investigate associated risk factors. RESEARCH DESIGN AND METHODS: Cross-sectional analysis of complications was assessed in three study periods (1990-1994 [T1], 1995-1998 [T2], and 1999-2002 [T3]) in adolescents matched for age and diabetes duration (n = 878, median age 14.6 years, median duration 7.5 years). Retinopathy was assessed by seven-field stereoscopic fundal photography, albumin excretion rate (AER) from three consecutive timed overnight urine collections, peripheral nerve function by thermal and vibration thresholds, and autonomic nerve function by cardiovascular reflexes. RESULTS: Retinopathy declined significantly (T1, 49%; T2, 31%; and T3, 24%; P < 0.0001), early elevation of AER (> or = 7.5 microg/min) declined (38, 30, and 25%, respectively, P = 0.022), and microalbuminuria (AER > or = 20 microg/min) declined (7, 3, and 3%, respectively; P = 0.017, T1 vs. T2 and T3). Autonomic nerve abnormalities were unchanged (18, 21, and 18%, respectively; P = 0.60), but peripheral nerve abnormalities increased (12, 19, and 24%, respectively; P = 0.0017). More patients were treated with three or more injections per day (12, 46, and 67%, respectively; P < 0.0001) and insulin dose increased (1.08, 1.17, and 1.22 units x kg(-1) x day(-1), respectively; P < 0.0001), but median HbA(1c) (A1C) was unchanged (8.5, 8.5, and 8.4%, respectively). BMI and height SD score increased: BMI 0.46, 0.67, and 0.79, respectively (P < 0.0001), and height -0.09, 0.05, and 0.27, respectively (P < 0.0001). CONCLUSIONS: Retinopathy and microalbuminuria declined over time in this cohort, but the increased rate of peripheral nerve abnormalities is of concern. Despite intensified management (higher insulin dose and more injections), A1C has not changed and remains well above the recommended targets for adolescents.

Adolescent↗

PubMed2004

A visual field abnormality: ocular or cerebral cause?

The visual field can be affected by disorders involving any part of the visual pathway, from the retina to the striate cortex. The pattern of visual field damage can indicate the location of the disorder. The case is presented here of an 8-year-old girl with congenital glaucoma. Initial perimetry appeared consistent with glaucomatous field loss; however, this evolved into a homonymous quadrantanopia, indicating the presence of a cerebral lesion as the cause. Computed tomography and magnetic resonance imaging scans detected a large middle cranial fossa arachnoid cyst. Postoperatively there was resolution of the visual field defects secondary to the arachnoid cyst. The pattern of field loss was pivotal in this patient's management. Attention must be paid when caring for the patient with a chronic disease to ensure that concurrent conditions are diagnosed.

Arachnoid Cysts↗

PubMed2003

Do all prepubertal years of diabetes duration contribute equally to diabetes complications?

OBJECTIVE: This study was designed to explore the timeline of protection against complications in prepubertal children with diabetes, in particular the effects of diabetes duration before age 5 years. RESEARCH DESIGN AND METHODS: In this study, 193 adolescents with prepubertal diabetes onset were followed longitudinally for retinopathy (early background and clinical) and microalbuminuria (albumin excretion rate >7.5 micro g/min and >20 micro g/min). Multiple logistic regression analysis was used to compare the effect of pre- and postpubertal diabetes duration on the risk of each complication in 90 subjects reassessed as young adults. For the entire cohort, Kaplan-Meier estimates were used to determine time free of each complication, and survival was compared in those diagnosed before and after age 5 years. Accelerated failure time modeling was used to estimate the effect of covariates, including diabetes duration before puberty, on the risk of complications. RESULTS: Prepubertal duration improved the prediction for retinopathy over postpubertal duration alone in the young adults. The survival-free period of retinopathy and microalbuminuria was significantly longer (2-4 years) for those diagnosed before age 5 years compared with those diagnosed after age 5 years. Time to onset of all complications increased progressively with longer diabetes duration before gonadarche. Higher HbA(1c) during adolescence had an independent effect on the risk of retinopathy and microalbuminuria. CONCLUSIONS: Prepubertal diabetes duration remains a significant predictor of retinopathy in young adults. The effect of time on the risk of retinopathy and microalbuminuria is nonuniform, with an increasing delay in the onset of complications in those with longer prepubertal duration. These findings are of major clinical importance when setting targets of glycemic control in young children who are at greatest risk of hypoglycemia.

Adolescent↗