Human Leukocyte Antigens class II (HLA II) gene profile from an admixed population of patients with type 1 diabetes with severe diabetic retinopathy: a nested case-control study in Brazil.

BACKGROUND: Although the well-established role of the HLA genes on the predisposition of type 1 diabetes (T1D), its contribution to the development and progression of diabetic retinopathy is still unclear, especially in admixed populations. We aimed to study the relationship between HLA alleles and severe diabetic retinopathy in a highly admixed population of T1D patients. METHODS: This was a nested case-control study based on a cross-sectional, nationwide survey conducted in Brazil. We included 117 patients with severe diabetic retinopathy and 117 random controls composed of T1D patients without retinopathy, matched for diabetes duration. HLA-class II genes (HLA-DRB1, -DQA1, and -DQB1) were genotyped using the SSO and NGS methods. RESULTS: Haplotypes HLA-DRB1*04:05 ~ DQA1*03:01 g ~ DQB1*03:02 (OR 1.75, CI 0.97-3.16, p value 0.058) and HLA-DRB1*13:02 ~ DQA1*01:02 ~ DQB1*06:04 (OR 5.18, CI 1.12-23.09, p value 0.019) were more prevalent on the severe DR group but they did not present statistically difference after Bonferroni correction. The most frequent haplotype on both groups was HLA-DRB1*03:01 ~ DQA1*05:01 g ~ DQB1*02:01 (29.6% on severe DR and 33.33% on the control group). CONCLUSIONS: Our study showed no influence of HLA genes on the development of DR. Further longitudinal data is needed to better understand the role of genetic factors on this multifactorial significant microvascular complication.

Genomic ancestry as a risk factor for diabetic retinopathy in patients with type 1 diabetes from an admixed population: a nested case-control study in Brazil.

AIMS: The influence of genetic factors on the development and progression of diabetic retinopathy is still unclear. Previous studies showed controversial results. We aimed to characterize the relationship between genomic ancestry and self-reported color/race with severe diabetic retinopathy in patients with type 1 diabetes belonging to a highly admixed population. METHODS: This study was a nested case-control based on data collected from a large cross-sectional, nationwide survey conducted in clinics from all five geographic regions of Brazil. For the present study, we included 414 individuals. Cases (n = 176) were considered if they had severe non-proliferative or proliferative diabetic retinopathy, and controls (n = 238) were type 1 diabetes patients without retinopathy, matched for diabetes duration by a range of 5 years. Indirect ophthalmoscopy was performed, and individual genomic ancestry was inferred using a panel of 46 ancestry informative markers. RESULTS: The backward stepwise logistic regression analysis showed that African genomic ancestry (OR 3.9, p = 0.045), HbA1c (OR 1.24, p = 0.001), glomerular filtration rate (OR 0.98, p < 0.001) and hypertension (OR 2.52, p < 0.001) were associated with severe diabetic retinopathy after adjusting for clinical and demographic data. Self-reported color/race was not statistically associated with diabetic retinopathy. CONCLUSIONS: Genomic ancestry, as well as clinical variables such as hypertension, impaired glomerular filtration rate and poor diabetes control (HbA1c), was important risk factor for the development of severe diabetic retinopathy. Further studies are needed, especially in highly admixed populations, to better understand the role of genomic ancestry and possible genes that might be associated with the development and/or progression of diabetic retinopathy.

Serum uric acid and renal function in patients with type 1 diabetes: a nationwide study in Brazil.

BACKGROUND: Diabetes nephropathy is a microvascular complication associated with high morbidity and mortality in patients with type 1 diabetes, and its pathogenesis is not fully understood. Our aim was to evaluate the association between levels of serum uric acid and renal function assessed by glomerular filtration rate (GFR) and albuminuria in patients with type 1 diabetes. METHODS: This is a multicenter, cross-sectional, observational study with 1686 patients, conducted between August 2011 and August 2014 in 14 public clinics from ten Brazilian cities. Renal function was estimated by CKD-EPI (adults) and by Schwartz (adolescents). RESULTS: We analyzed 1686 patients, aged 30.1 ± 12.0, with 15.4 ± 9.3 years of duration of diabetes; 55.8% were female and 54.0% were Caucasians. Serum uric acid was related to renal function, with a mean of 4.8 ± 1.4 (in the normal renal function group) vs 5.2 ± 2.0 (GFR ≥ 60 ml/min and albuminuria) vs 6.5 ± 2.6 mg/dl (GFR < 60 ml/min). In the pooled group, multivariate analysis showed an inverse correlation between serum uric acid and GFR (r = - 0.316, p < 0.001) with a decrease of 4.11 ml/min in the GFR for every increase of 1 mg/dl in serum uric acid. Considering only patients with normal renal function (n = 1170), a decrease of 2.04 ml/min in the GFR for every increase of 1 mg/dl in Serum uric acid was noted using multivariate analysis. CONCLUSIONS: Patients with higher levels of serum uric acid have worse renal function, independently of HbA1c or duration of diabetes, which persisted even in patients with normal renal function. Further prospective studies are necessary to establish if patients with higher serum uric acid may have an elevated risk for developing chronic kidney disease.

Regional differences in the prevalence of diabetic retinopathy: a multi center study in Brazil.

BACKGROUND: Diabetic retinopathy has a significant impact in every healthcare system. Despite that fact, there are few accurate estimates in the prevalence of DR in Brazil's different geographic regions, particularly proliferative DR and diabetic macular edema. This study aims to determine the prevalence of diabetic retinopathy in Brazil's five continental regions and its determinant factors. METHODS: This multi center, cross-sectional, observational study, conducted between August 2011 and December 2014, included patients with type 1 diabetes from the 5 Brazilian geographic regions (South, Southeast, North, Northeast and Midwest). During a clinical visit, a structured questionnaire was applied, blood sampling was collected and each patient underwent mydriatic binocular indirect ophthalmoscopy evaluation. RESULTS: Data was obtained from 1644 patients, aged 30.2 ± 12 years (56.1% female, 54.4% Caucasian), with a diabetes duration of 15.5 ± 9.3 years. The prevalence of diabetic retinopathy was 242 (36.1%) in the Southeast, 102 (42.9%) in the South, 183 (29.9%) in the North and Northeast and 54 (41.7%) in the Midwest. Multinomial regression showed no difference in the prevalence of non-proliferative diabetic retinopathy in each geographic region, although, prevalence of proliferative diabetic retinopathy (p = 0.022), and diabetic macular edema (p = 0.003) was higher in the Midwest. Stepwise analyses reviled duration of diabetes, level of HbA1c and hypertension as independent variables. CONCLUSIONS: The prevalence of non proliferative diabetic retinopathy in patients with type 1 diabetes was no different between each geographic region of Brazil. The Midwest presented higher prevalence of proliferative diabetic retinopathy and diabetic macular edema. Duration of DM and glycemic control is of central importance to all. Hypertension is another fundamental factor to every region, at special in the South and Southeast. Glycemic control and patients in social and economic vulnerability deserves special attention in the North and Northeast of Brazil.