Serum Albumin, but not Bilirubin, is Associated with Diabetic Chronic Vascular Complications in a Chinese Type 2 Diabetic Population

The non-linear relationship between serum albumin and diabetic retinopathy in type 2 diabetes mellitus: a secondary analysis based on a cross-sectional study

BACKGROUND

Most studies had shown a linear relationship between serum albumin (sALB) and the prevalence of diabetic retinopathy (DR). Thus, the purpose of this study is to investigate whether their relationship is non-linear.

METHODS

We included 426 patients with type 2 diabetes who were hospitalized in Guangdong Provincial People's Hospital from December 2017 to November 2018. The outcome was the prevalence of DR. A two-piecewise logistics regression model was performed to identify the non-linear relationship between sALB and the prevalence of DR. The inflection point was calculated to determine the saturation effect through the maximum likelihood ratio and a recursive algorithm.

RESULTS

DR was diagnosed in 167 of 426 type 2 diabetic patients. The relationship between sALB and DR was nonlinear. When sALB was less than 38.10 g/L, a significant negative association was observed (OR = 0.82; 95% CI, 0.72-0.94; P = 0.0037), while no significant association was observed when sALB was greater than 38.10 g/L (OR = 1.12; 95% CI, 0.92-1.35; P = 0.2637).

CONCLUSIONS

The relationship between sALB and the prevalence of DR is non-linear. sALB is negatively associated with the prevalence of DR when sALB is less than 38.10 g/L. Our findings need to be confirmed by further prospective research.

Multi-omics analysis reveals the potential pathogenesis and therapeutic targets of diabetic kidney disease

Clinicians have long been interested in understanding the molecular basis of diabetic kidney disease (DKD)and its potential treatment targets. Its pathophysiology involves protein phosphorylation, one of the most recognizable post-transcriptional modifications, that can take part in many cellular functions and control different metabolic processes. In order to recognize the molecular and protein changes of DKD kidney, this study applied Tandem liquid chromatography-mass spectrometry (LC-MS/MS) and Next-Generation Sequencing, along with Tandem Mass Tags (TMT) labeling techniques to evaluate the mRNA, protein and modified phosphorylation sites between DKD mice and model ones. Based on Gene Ontology (GO) and KEGG pathway analyses of transcriptome and proteome, The molecular changes of DKD include accumulation of extracellular matrix, abnormally activated inflammatory microenvironment, oxidative stress and lipid metabolism disorders, leading to glomerulosclerosis and tubulointerstitial fibrosis. Oxidative stress has been emphasized as an important factor in DKD and progression to ESKD, which is directly related to podocyte injury, albuminuria and renal tubulointerstitial fibrosis. A histological study of phosphorylation further revealed that kinases were crucial. Three groups of studies have found that RAS signaling pathway, RAP1 signaling pathway, AMPK signaling pathway, PPAR signaling pathway and HIF-1 signaling pathway were crucial for the pathogenesis of DKD. Through this approach, it was discovered that targeting specific molecules, proteins, kinases and critical pathways could be a promising approach for treating DKD.

Association between serum total bilirubin and diabetic kidney disease in US diabetic patients

Background

Bilirubin has been widely reported to be a protective factor against diabetic kidney disease (DKD) in Asian populations. However, few large-sample analyses have been conducted in American populations. This study aimed to investigate the association between serum total bilirubin (STB) level and DKD in a US diabetic cohort.

Methods

This cross-sectional study enrolled participants from the National Health and Nutrition Examination Survey (NHANES) 2003-2018. Univariate and multivariate logistic regression analyses were performed to assess the association between STB level and DKD. Three models were conducted to control the potential confounding factors. Subgroup analysis was carried out for further validation.

Results

Among the 5,355 participants, the median age [interquartile range (IQR)] was 62 [52-71] years; 2,836 (52.96%) were male, and 1,576 (29.43%) were diagnosed with DKD. In the entire cohort, no significant association between STB level and DKD was observed in any logistic regression models (p > 0.05). Subgroup analysis revealed that, in U.S. diabetic males, STB levels > 11.98 µmol/L were associated with a nearly 30% lower risk of DKD than STB levels ≤ 8.55 µmol/L. Additionally, a moderate STB level (8.56-11.98 μmol/L) was found associated with a nearly 25% lower risk of DKD in U.S. diabetic patients over 65 years old.

Conclusion

The association of STB level with DKD may depict differences across diverse populations, among which the impact of race, sex, and age requires thorough consideration and relevant inferences should be interpreted cautiously.

Association of prognostic nutritional index with the risk of all-cause mortality and cardiovascular mortality in patients with type 2 diabetes: NHANES 1999-2018

INTRODUCTION

There is little bulk clinical evidence on nutritional status and mortality in patients with diabetes. The purpose of this study was to examine the relationship between prognostic nutritional index (PNI) and all-cause mortality and cardiovascular mortality in adults with diabetes.

RESEARCH DESIGN AND METHODS

This study included 5916 adult patients with diabetes from the National Health and Nutrition Examination Survey 1999-2018. Cox proportional risk models were used to estimate risk ratios (HRs) and 95% CIs for all-cause mortality, cardiovascular disease (CVD) mortality.

RESULTS

During a mean follow-up of 8.17 years, there were 1248 deaths from all causes and 370 deaths from CVD. After multivariate adjustment, the risk of all-cause mortality was reduced by 24%, 38%, and 28% in Q2 (49.0-52.99), Q3 (53.0-57.99), and Q4 (≥58.0), respectively, compared with Q1 (PNI<49.0). The risk of cardiovascular mortality was reduced by 30%, 27%, and 26%, respectively. Consistent results were observed in the subgroup analysis.

CONCLUSIONS

Lower serum PNI levels were significantly associated with higher all-cause and CVD mortality. These findings suggest that maintaining an appropriate range of serum PNI status may reduce the risk of death in patients with diabetes.

Correlation Between Fibrinogen/Albumin and Diabetic Peripheral Neuropathy

Purpose

This study aimed to examine the correlation between fibrinogen/albumin (FAR) and diabetic peripheral neuropathy (DPN).

Patients and Methods

A total of 342 patients were included and categorized into either the DPN group or the Non-DPN (NDPN) group based on their DPN status. The FAR index was determined by calculating the ratio of fibrinogen (FIB) to serum albumin (ALB), multiplied by 100. The participants were then divided into a High-FAR group and a Low-FAR group using the median FAR value as the threshold. Neurophysiological data were collected from the participants, which included motor conduction velocity (MCV) and sensory conduction velocity (SCV).

Results

The DPN group displayed higher FAR levels [(DPN vs NDPN:6.72 (5.89,7.74) vs 5.94±1.14], in addition to slower SCV and MCV data compared to the NDPN group. The high FAR group had a higher prevalence of DPN (78.9% vs 55.6%) (P<0.05). There was a negative correlation between FAR and NCV, including bilateral median nerve SCV, left ulnar nerve SCV, bilateral median nerve MCV, bilateral common peroneal nerve MCV, bilateral tibial nerve MCV, and left ulnar nerve MCV. FAR was revealed to be an independent risk factor for the development of DPN in patients and demonstrated a greater predictive value for DPN development in Type 2 diabetes mellitus (T2DM) compared with FIB, HbA1c.

Conclusion

The results suggest that monitoring FAR levels in patients with T2DM could identify those at higher risk for developing DPN, making the FAR index a valuable predictor of DPN development. Furthermore, since FAR has an inverse relationship with NCV, it stands to reason that high FAR levels may indicate nerve damage and slower conduction velocities. Thus, managing FAR could prove beneficial in both preventing and delaying the onset of DPN in T2DM patients.

The V-shaped curve relationship between fasting plasma glucose and human serum albumin in a large health checkup population in China

BACKGROUND

This study aimed to investigate the relationship between fasting plasma glucose (FPG) and human serum albumin (HSA) in a large health checkup population in China.

METHODS

In this cross-sectional health checkup study, we enrolled a population of 284,635 subjects from Wuhu between 2011 and 2016. All participants completed the physical examination, blood biochemical examination, and blood routine examination.

RESULTS

The prevalence of diabetes in men and women was 6.11% and 2.98%, respectively. The average level of HSA and FPG was significantly higher in men than in women (48.44 ± 3.25 vs. 47.14 ± 3.22, P < 0.0001; 5.50 ± 1.26 vs. 5.26 ± 0.94, P < 0.0001). There were significant differences in blood biochemistry and blood routine values by gender. After adjusting for confounding factors, the results showed that FPG and HSA were a V-shaped curve, and the threshold value of HSA was 40.7 mmol/L. FPG and HSA still showed a V-shaped curve after stratification by gender and age. In the male group, FPG decreased with HSA when HSA<42.3 mmol/L, and increased when HSA ≥ 42.3 mmol/L. In the female group, FPG decreased with HSA when HSA<35.7 mmol/L, and increased when HSA ≥ 35.7 mmol/L. In the age<65 group, FPG decreased with HSA when HSA<37.5 mmol/L, and increased when HSA ≥ 37.5 mmol/L. In the age ≥ 65 group, FPG decreased with HSA when HSA<43.2 mmol/L, and increased when HSA ≥ 43.2 mmol/L.

CONCLUSIONS

A V-shape relationship exists between fasting plasma glucose and human serum albumin among the Chinese health checkup population studied.

The Ratio of Fibrinogen to Albumin is Related to the Occurrence of Retinopathy in Type 2 Diabetic Patients

Purpose

Type 2 diabetic retinopathy is a long-term chronic inflammatory disease. The aim of this study was to investigate the relationship between fibrinogen to albumin ratio (FAR) and retinopathy in type 2 diabetic patients.

Methods

This was a retrospective study that included 500 patients with type 2 diabetes mellitus (T2DM), and were divided into non-diabetic retinopathy group (NDR, n=297) and diabetic retinopathy group (DR, n=203) according to fundus examination findings, and the DR group was further divided into non-proliferative retinopathy group (NPDR, n=182) and proliferative retinopathy group (PDR, n=21). Baseline data of patients were collected, and the fibrinogen to albumin ratio (FAR) and neutrophil to lymphocyte ratio (NLR) were calculated to analyze the correlation between FAR and NLR and type 2 diabetic retinopathy.

Results

The FAR and NLR were significantly higher in the DR group compared with the NDR group (both P < 0.001). Spearman correlation analysis showed that FAR was positively correlated with NLR and DR (P < 0.05). As the FAR quartile increased, the prevalence of DR increased (14.8%, 16.7%, 25.1%, and 43.30%, respectively; P < 0.05). Multifactorial logistic regression analysis showed that FAR, diabetic course, systolic blood pressure (SBP) and diabetic peripheral neuropathy (DPN) were risk factors for the development of DR in patients with T2DM. The area under the ROC curve for FAR to predict DR progression was 0.708, with an optimal critical value of 7.04, and the area under the ROC curve for diabetes duration and SBP to predict DR was 0.705 and 0.588, respectively.

Conclusion

Our findings show for the first time that FAR is an independent risk factor for assessing DR in patients with type 2 diabetes.

Malnutrition in elderly patients with type 2 diabetes mellitus in a Nigerian tertiary hospital: A cross-sectional study

Introduction

The global population of the elderly with type 2 diabetes mellitus (T2DM) is growing due to improvement in DM care and increased life expectancy. Malnutrition is a recognized complication of DM especially in the elderly. However, despite the impact of malnutrition on the overall outcome of the elderly with DM, it has not received adequate attention.

Aim

To determine the prevalence of malnutrition and associated factors in the elderly with T2DM.

Methods

This was a cross-sectional study that involved 96 elderly with T2DM and 96 age and sex matched elderly without T2DM as controls. Malnutrition was assessed using mini-nutritional assessment-short form (MNA-SF), hypoalbuminemia and body mass index (BMI). The factors associated with some malnutrition indices were determined.

Results

The mean age of T2DM and non-T2DM groups were 66.73 ± 5.18 years and 66.78 ± 5.25 years respectively. The observed malnutrition indices among elderly with T2DM and controls were hypoalbuminemia (79.2% vs 25.0%; P ≤0.001); overweight and obesity (58.3% vs 24.0%); and underweight (16.7% vs 4.2%). According to MNA-SF, malnutrition (7.3% vs 0%) and at risk of malnutrition (42.7% vs 16.7%) were significantly more prevalent among elderly with T2DM compared to controls (P ≤0.001). On logistic regression, the significant predictors of malnutrition were male gender (AOR:2.70; CI:1.11-6.55; P = 0.028) and albuminuria (AOR:3.14; CI:1.18-8.35; P = 0.022) and poor glycemic control (AOR:7.05; CI:2.01-24.71; P = 0.002).

Conclusion

Malnutrition is highly prevalent in elderly with T2DM. Poor glycemic control, albuminuria and male gender were significant predictors of malnutrition in this study. Nutritional assessment should be included in the routine DM care especially among the elderly.

Prognostic nutritional index as a novel marker for diabetic retinopathy in individuals with type 2 diabetes mellitus

PURPOSE

In recent years, the prognostic nutritional index (PNI), an easily obtainable nutritional inflammatory marker, has been introduced as an independent prognostic indicator for various types of cancers and cardiovascular diseases. However, its clinical importance in the area of ophthalmology is not well known yet. We aimed to elucidate the association between the PNI and the occurrence of diabetic retinopathy (DR) in patients with type 2 diabetes mellitus (T2DM).

METHODS

In this cross-sectional study, the PNI was applied to 128 consecutive patients with T2DM. The relationship between the PNI and the occurrence of DR was examined. PNI was calculated as 10× (serum albumin) + 0.005 × (total lymphocyte count). The risk factors for DR were evaluated using multivariate logistic regression analysis. A receiver operating characteristic (ROC) curve analysis of PNI for predicting DR was performed.

RESULTS

Patients with DR had significantly lower levels of PNI than those without DR (41.20 ± 4.81 and 44.49 ± 3.10, respectively,P< 0.001). Multivariate regression analysis indicated that PNI, together with the duration of diabetes and creatinine, was an independent factor for DR occurrence (odds ratio, 0.885; 95% confidence interval: 0.735-0.971;P= 0.017). ROC curve analysis revealed that the best cutoff value of PNI was 43 (area under the curve: 0.713; sensitivity: 74%; specificity: 64%).

CONCLUSION

A lower PNI value is common among T2DM patients with DR and is strongly associated with the occurrence of DR. The PNI might be a useful biomarker for identifying DR to improve the risk stratification and management of T2DM patients.

Syringic Acid Ameliorates Cardiac, Hepatic, Renal and Neuronal Damage Induced by Chronic Hyperglycaemia in Wistar Rats: A Behavioural, Biochemical and Histological Analysis

This study investigated the effects of syringic acid (SA) on renal, cardiac, hepatic, and neuronal diabetic complications in streptozotocin-induced neonatal (nSTZ) diabetic rats. STZ (110 mg/kg i.p) was injected into Wistar rat neonates as a split dose (second and third postnatal day). Diabetes mellitus was diagnosed in adults by measuring fasting blood glucose levels, urine volume, and food and water intake. The treatment of SA (25 mg/kg, 50 mg/kg p.o) was given from the 8th to 18th postnatal week. To assess the development of diabetic complications and the effect of therapy, biochemical indicators in serum and behavioural parameters were recorded at specific intervals during the study period. SA (25 mg/kg, 50 mg/kg p.o) treatment reduced hyperglycaemia, polydipsia, polyphagia, polyuria, relative organ weight, cardiac hypertrophic indices, inflammatory markers, cell injury markers, glycated haemoglobin, histopathological score, and oxidative stress, and increased Na/K ATPase activity. These findings suggest that SA might significantly alleviate diabetic complications and/or renal, neuronal, cardiac, and hepatic damage in nSTZ diabetic rats.

Associations of Nutritional, Environmental, and Metabolic Biomarkers with Diabetes-Related Mortality in U.S. Adults: The Third National Health and Nutrition Examination Surveys between 1988-1994 and 2016

Background: Nutritional, environmental, and metabolic status may play a role in affecting the progression and prognosis of type 2 diabetes. However, results in identifying prognostic biomarkers among diabetic patients have been inconsistent and inconclusive. We aimed to evaluate the associations of nutritional, environmental, and metabolic status with disease progression and prognosis among diabetic patients. Methods: In a nationally representative sample in the NHANES III (The Third National Health and Nutrition Examination Survey, 1988−1994), we analyzed available data on 44 biomarkers among 2113 diabetic patients aged 20 to 90 years (mean age: 58.2 years) with mortality data followed up through 2016. A panel of 44 biomarkers from blood and urine specimens available from NHANES III were included in this study and the main outcomes as well as the measures are mortalities from all-causes. We performed weighted logistic regression analyses after controlling potential confounders. To assess incremental prognostic values of promising biomarkers beyond traditional risk factors, we compared c-statistics of the adjusted models with and without biomarkers, separately. Results: In total, 1387 (65.2%) deaths were documented between 1988 and 2016. We observed an increased risk of all-cause mortality associated with higher levels of serum C-reactive protein (p for trend = 0.0004), thyroid stimulating hormone (p for trend = 0.04), lactate dehydrogenase (p for trend = 0.02), gamma glutamyl transferase (p for trend = 0.02), and plasma fibrinogen (p for trend = 0.03), and urine albumin (p for trend < 0.0001). In contrast, higher levels of serum sodium (p for trend = 0.005), alpha carotene (p for trend = 0.006), and albumin (p for trend = 0.005) were associated with a decreased risk of all-cause mortality. In addition, these significant associations were not modified by age, sex, or race. Inclusion of thyroid stimulating hormone (p = 0.03), fibrinogen (p = 0.01), and urine albumin (p < 0.0001), separately, modestly improved the discriminatory ability for predicting all-cause mortality among diabetic patients. Conclusions: Our nationwide study findings provide strong evidence that some nutritional, environmental, and metabolic biomarkers were significant predictors of all-cause mortality among diabetic patients and may have potential clinical value for improving stratification of mortality risk.

The correlation between serum albumin and diabetic retinopathy among people with type 2 diabetes mellitus: NHANES 2011–2020

Objectives

The objective of this research aimed to investigate the correlation involving serum albumin with diabetic retinopathy (DR) in patients with type 2 diabetes mellitus (T2DM).

Methods

From 2011 to 2020, the National Health and Nutrition Examination Survey (NHANES) surveyed 45462 participants. We used the relevant data to conduct descriptive statistics, linear regression, and Logistic regression analysis.

Results

After adjusting for age, sex, and race, as well as all other variables, serum albumin was significantly negatively related to DR (P<0.001). Furthermore, after controlling for confounding factors, the third quartile (Q3) and the fourth quartile (Q4) had quite a negative significant relationship with the incidence of DR (P<0.01). The second quartile had a significant positive correlation with DR, whereas the observed negative correlations were not statistically meaningful (P>0.05).

Conclusion

Albumin levels in the serum have a quantitatively significant negative correlation with DR. Serum albumin levels in the blood can be used as a reference point for protracted follow-up of people with T2DM.

Prediction of 3-year risk of diabetic kidney disease using machine learning based on electronic medical records

BACKGROUND

Established prediction models of Diabetic kidney disease (DKD) are limited to the analysis of clinical research data or general population data and do not consider hospital visits. Construct a 3-year diabetic kidney disease risk prediction model in patients with type 2 diabetes mellitus (T2DM) using machine learning, based on electronic medical records (EMR).

METHODS

Data from 816 patients (585 males) with T2DM and 3 years of follow-up at the PLA General Hospital. 46 medical characteristics that are readily available from EMR were used to develop prediction models based on seven machine learning algorithms (light gradient boosting machine [LightGBM], eXtreme gradient boosting, adaptive boosting, artificial neural network, decision tree, support vector machine, logistic regression). Model performance was evaluated using the area under the receiver operating characteristic curve (AUC). Shapley additive explanation (SHAP) was used to interpret the results of the best performing model.

RESULTS

The LightGBM model had the highest AUC (0.815, 95% CI 0.747-0.882). Recursive feature elimination with random forest and SHAP plot based on LightGBM showed that older patients with T2DM with high homocysteine (Hcy), poor glycemic control, low serum albumin (ALB), low estimated glomerular filtration rate (eGFR), and high bicarbonate had an increased risk of developing DKD over the next 3 years.

CONCLUSIONS

This study constructed a 3-year DKD risk prediction model in patients with T2DM and normo-albuminuria using machine learning and EMR. The LightGBM model is a tool with potential to facilitate population management strategies for T2DM care in the EMR era.

Association Between Serum Albumin Level and Microvascular Complications of Type 2 Diabetes Mellitus

OBJECTIVE

To analyze the associations between serum albumin (sALB) level and diabetic microvascular complications, including diabetic retinopathy (DR) and diabetic kidney disease (DKD), in patients with type 2 diabetes mellitus (T2DM).

METHODS

This retrospective study included 951 hospitalized patients with T2DM who had completed screening for DR and DKD during hospitalization. Patients were divided into three groups according to sALB tertiles. Multivariate logistic regression analysis was used to assess the association of sALB with microvascular complications.

RESULTS

The prevalence of DR, DKD and macroalbuminuria increased with decreasing sALB levels. Multivariate logistic regression analysis showed that lower levels of sALB (Q1) were associated with higher risk of DR (odds ratio [OR]: 1.59, 95% confidence interval [CI]: 1.12-2.26), DKD (OR: 3.00, 95% CI: 2.04-4.41) and macroalbuminuria (OR: 9.76, 95% CI: 4.62-20.63) compared with higher levels of sALB (Q3) after adjustment for other risk factors. After stratification by sex and age, the effect of lower levels of sALB (Q1) on DR incidence was more obvious in patients with male (OR: 1.60, 95% CI: 1.00-2.56), and aged<65 years (OR: 1.74, 95% CI: 1.14-2.65) (P < 0.05 for all); the effect of lower levels of sALB (Q1) on the incidence of DKD was significant in both males (OR: 3.78, 95% CI: 2.26-6.32) and females (OR: 2.35, 95% CI: 1.26-4.35) (P < 0.05 for all), while only the age <65 years (OR: 3.46, 95% CI: 2.16-5.53) was significant in the age subgroup (P < 0.001).

CONCLUSION

Decreased sALB levels may be an independent risk indicator of DR and DKD in patients with T2DM, and significantly associated with DKD progression. For DR screening, special attention should be paid to men aged <65 years, while screening for DKD should pay attention to people <65 years old.

Risk Factors for Progression of CKD with and without Diabetes

OBJECTIVE

We aim to identify independent risk factors to predict CKD progression to end stage renal disease (ESRD) in patients with or without diabetes.

METHODS

In this retrospective study, we enrolled CKD stage 3-4 patients between January 2013 and December 2018 and followed them until December 2020 or the initiation of dialysis. We used Kaplan-Meier to plot the survival curve. Univariate and multivariable Cox proportional hazards model was used to explore risk factors affecting the progression of CKD. The final model was used to construct nomogram for predicting CKD progression. Calibration plots and concordance index (C-index) were used to evaluate the accuracy and discrimination of the risk model.

RESULTS

We enrolled 309 CKD patients, including 80 cases in G3a, 98 cases in G3b, and 131 cases in G4. Among them, 141 patients had diabetes and 168 did not. The mean age of patients at enrolled was 57.86 ± 15.10 years, and 67% were male. The median follow-up time was 25.6 months. There were 81 patients (26.2%) that started dialysis in the total CKD cohort, 52 cases (36.9%) in the CKD with diabetes group, and 29 cases (17.3%) in the CKD without diabetes group. Hypoalbuminemia (HR =2.655, P < 0.001), proteinuria (HR =2.592, P = 0.042), increased LDL (HR =2.494, P < 0.001), diabetes (HR =2.759, P < 0.001), hypertension (HR =3.471, P = 0.037), and CKD stage (HR =2.001, P = 0.046) were risk factors for CKD progression to ESRD in the overall population. For those without diabetes, only hypoalbuminemia (HR =2.938, P = 0.030) was a risk factor for CKD progression to ESRD. For those with diabetes, both hypoalbuminemia (HR =2.758, P = 0.002), the increased level of LDL (HR =3.982, P < 0.001), and CKD stage (HR =3.781, P = 0.001) were risk factors for CKD progression to ESRD. The C-index of the final nomograms was 0.760 (P < 0.001).

CONCLUSIONS

The results from our risk factor model suggest that CKD disease progression can be predicted and early strategic intervention is necessary for CKD patients to avoid renal function deterioration.

A Clinical Epidemiological Analysis of Prognostic Nutritional Index Associated with Diabetic Retinopathy

PURPOSE

Prognostic nutritional index (PNI) is an effective tool to evaluate the nutritional conditions and predict prognosis, but clinical data are limited for the use of PNI in diabetic retinopathy (DR). This study aimed to investigate the relationship of PNI with the prevalence and severity of DR in patients with type 2 diabetes mellitus (T2DM).

PATIENTS AND METHODS

This cross-sectional analysis enrolled 1023 individuals with T2DM hospitalized between 2017-2020. PNI was calculated as 10 × serum albumin (g/l) + 0.005 × total lymphocyte count (cells/mL). DR severity was categorized as no, nonproliferative, and vision-threatened DR (VTDR) according to the modified Airlie House classification. Multivariate-adjusted odds ratio (OR) with 95% confidence interval (CI) for the prevalent DR in the top (Q4) compared with the bottom quartile (Q1) of PNI levels were estimated by using logistic regression analyses.

RESULTS

PNI levels were significantly lower in individuals with VTDR than those with no and nonproliferative DR (both P < 0.001), and the proportions of individuals with DR were significantly decreased in the top quartile compared with the bottom quartile of PNI levels (P < 0.001). After adjustments for age, gender, DM duration, obesity-related risk factors and clinical biochemical parameters, the higher levels of PNI were significantly associated with a lower prevalence of DR (Q4 vs Q1: OR = 0.402, 95% CI: 0.250-0.649, P < 0.001), with a 5.9% reduction in the prevalence of DR for a per-unit increment in the levels of PNI (OR = 0.941, 95% CI: 0.911-0.972, P < 0.001). The association of PNI and obesity-related indexes (body mass index and waist circumference) with the severity of DR was independent of each other (P<0.001).

CONCLUSION

PNI was inversely and independently associated with the severity and prevalence of DR, which suggested that PNI could likely be used to predict DR prognosis in clinical practice.

Plasma melatonin levels in patients with diabetic retinopathy secondary to type 2 diabetes

BACKGROUND

Melatonin is reported to be related to diabetes mellitus (DM) risk; however, the effect of melatonin on diabetic retinopathy (DR) risk remains unclear.

AIM

The aim of this study was to determine the effect of melatonin on DR risk.

METHODS

A hospital-based case-control study was conducted from January 2020 to June 2020. DR was assessed using the Diabetic Retinopathy preferred practice pattern (PPP)-updated 2019 criteria. The participants were divided into the DM cases without DR (NDR) group, non-proliferative DR (NPDR) group and proliferative DR (PDR) group. Plasma melatonin concentration was detected with the enzyme-linked immunosorbent assay kit. The relationship between plasma melatonin concentration and DR risk as well as severity was assessed.

RESULTS

It was found that plasma melatonin was 72.83 ± 16.25, 60.38 ± 13.43, 44.48 ± 10.30 and 44.69 ± 8.95 pg/mL in healthy controls, NDR group, NPDR and PDR group, respectively. In addition, it was found that plasma melatonin could be used as a potential diagnostic biomarker for DR (AUC = 0.893, P < 0.001). There was a significant positive relationship between total bilirubin and melatonin content (P < 0.001) based on the correlation assay. Significant associations between total bilirubin and melatonin content were also detected in the NPDR (R² = 0.360, P < 0.001) and PDR (R² = 0.183, P < 0.001) groups.

CONCLUSION

The data obtained in this study demonstrated that plasma melatonin concen-tration was decreased in DR cases and could be used as a sensitive and specific marker for the diagnosis of DR. A significant positive relationship between total bilirubin and melatonin was detected. More related studies are required to understand the role of melatonin in DR.