The role of pulse pressure in navigating the paradigm of chronic kidney disease progression in type 2 diabetes mellitus.

BACKGROUND AND AIMS: Arterial stiffness is a risk factor for chronic kidney disease progression (CKD). Pulse pressure is a surrogate marker of arterial stiffness. It is unclear if pulse pressure predicts CKD progression in type 2 diabetes mellitus. METHODS: This was prospective study involving 1494 patients with estimated glomerular filtration rate (eGFR) ≥ 15 ml/min/1.73 m2. Carotid-femoral pulse wave velocity was measured using applanation tonometry. Pulse pressure was calculated as difference between systolic and diastolic blood pressures. CKD progression was defined as worsening of eGFR categories (stage 1, ≥ 90 ml/min/1.73 m2; stage 2, 60-89 ml/min/1.73 m2; stage 3a, 45-59 ml/min/1.73 m2; stage 3b, 30-44 ml/min/1.73 m2; stage 4; 15-29 ml/min/1.73 m2; and stage 5, < 15 ml/min/1.73 m2) with ≥ 25% decrease in eGFR from baseline. RESULTS: After follow-up of up to 6 years, CKD progression occurred in 33.5% of subjects. Subjects in 2nd, 3rd and 4th quartiles of peripheral pulse pressure experienced higher risk of CKD progression with unadjusted hazard ratios (HRs) 1.55 [95% confidence interval (CI) 1.13-2.11; p = 0.006], 2.58 (1.93-3.45; p < 0.001) and 3.41 (2.58-4.52; p < 0.001). In the fully adjusted model, the association for 2nd, 3rd and 4th quartiles remained with HRs 1.40 (1.02-1.93; p = 0.038), 1.87 (1.37-2.56; p < 0.001) and 1.75 (1.25-2.44; p = 0.001) respectively. Similarly, 2nd, 3rd and 4th quartiles of aortic pulse pressure were associated with higher hazards of CKD progression with HRs 1.73 (1.25-2.40; p = 0.001), 1.65 (1.18-2.29; p = 0.003) and 1.81 (1.26-2.60; p = 0.001). Increasing urinary albumin-to-creatinine ratio accounted for 44.0% of the association between peripheral pulse pressure and CKD progression. CONCLUSIONS: Individuals with high pulse pressure were more susceptible to deterioration of renal function. Pulse pressure could potentially be incorporated in clinical practice as an inexpensive and readily available biomarker of renal decline in type 2 diabetes mellitus. Graphic abstract.

Association between vascular measures and cognitive function in type 2 diabetes.

AIM: To examine correlation between vascular measures and cognitive performance in type 2 diabetes (T2D). METHODS: This was a cross-sectional study on patients (N = 1167) aged ≥45 years attending Diabetes Centre in a tertiary hospital and primary care polyclinic. The following vascular measures were measured: systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), pulse pressure (PP), pulse wave velocity (PWV) and augmentation index (AI). Cognition was assessed by Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Multiple linear regression was used to examine relationships between vascular measures and cognition, adjusting for demographics, education, depression, clinical covariates and presence of APOE Ɛ4 allele. RESULTS: In unadjusted analyses, all the vascular measures, except for MAP, were associated with RBANS total score. In fully adjusted analyses, the association with RBANS total score persisted for peripheral PP, aortic PP and aortic DBP with ßs -0.05 (95%CI -0.07 to -0.02; p = 0.001), -0.04 (95%CI -0.06 to -0.01; p = 0.002) and 0.05 (95%CI 0.00 to 0.09; p = 0.033). Association between peripheral and aortic PP and RBANS total score was unaffected by age-stratification (age <60 and ≥60 years). In contrast, significant association between aortic DBP and RBANS total score was only observed for those ≥60 years. Peripheral and aortic PP (which estimate pulsatility) are negatively associated with attention, visuospatial/constructional and language ability. CONCLUSIONS: Peripheral and aortic PP, and aortic DBP were independently correlated with cognitive performance globally and in multiple domains. Further research should be conducted to establish the clinical relevance and importance.

Association between Lower Extremity Skeletal Muscle Mass and Impaired Cognitive Function in Type 2 Diabetes.

Lower extremity skeletal muscle mass (LESM) in Type 2 Diabetes (T2D) has been linked to adverse clinical events, but it is not known whether it is associated with cognitive difficulties. We conducted a cross-sectional study on 1,235 people (mean age 61.4 ± 8.0 years) with T2D under primary and secondary care in Singapore. Bioelectrical impedance analyses (BIA) measures of upper extremity skeletal muscle mass (UESM), LESM and appendicular skeletal muscle index (SMI) were related to the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) measures of cognition, in multiple linear regression. In multivariable models, tertile 1 LESM (b = -2.62 (-3.92 to -1.32)) and tertile 2 LESM (b = -1.73 (-2.73 to -0.73)), referenced to tertile 3) were significantly associated with decreased RBANS total score. Significant associations of LESM with cognitive domain performances were observed for tertile 1 (b = -3.75 (-5.98 to -1.52)) and tertile 2 (b = -1.98 (-3.69 to -0.27)) with immediate memory, and for tertile 1 (b = -3.05 (-4.86 to -1.24)) and tertile 2 (b = -1.87 (-3.25 to -0.48)) with delayed memory, and for tertile 1 (b = -2.99 (-5.30 to -0.68)) with visuospatial/constructional ability. Tertile 1 SMI (b = -1.94 (-3.79 to -0.08) and tertile 2 SMI (b = -1.75 (-3.14 to -0.37)) were also associated with delayed memory. There were no associations between UESM with cognitive performance. Lower LESM may be a useful marker of possible co-occuring cognitive dysfunction.

Association of traditional and novel measures of central obesity with cognitive performance in older multi-ethnic Asians with type 2 diabetes.

Literature evaluating the relationship between central obesity and cognitive deficits in type 2 diabetes (T2DM) remains scarce. This cross-sectional analysis explored the association of novel and traditional central obesity measures with cognitive performance in older (aged ≥60 years) non-demented multi-ethnic Asians with T2DM, including a stratified analysis by body mass index (BMI). Cognitive function was assessed using the Repeatable Battery for the Assessment of Neuropsychological Status. Central obesity measures including visceral fat area (VFA), waist circumference, waist:hip ratio, waist:height ratio, abdominal volume index, body roundness index and conicity index were measured and/or computed. In our cohort (N = 677; mean age = 67 ± 5 years, 51.7% men), VFA emerged as an associate of overall cognitive performance after covariate adjustment and Bonferroni correction (ß = -.10, 95% CI = -0.18, -0.03), outperforming the other adiposity indices. Specifically, VFA was inversely associated with delayed memory and language scores. Additionally, compared with normal-weight individuals, excess visceral obesity (VFA ≥100 cm2 ) was independently associated with lower cognitive scores to a greater extent in normal BMI (<23 kg/m2 ) adults than in those with high BMI (≥23 kg/m2 ). Assessment and management of visceral adiposity may help to prevent cognitive decline in older people with T2DM, and reduce the global burden of dementia in ageing populations.

Plasma osteoprotegerin as a biomarker of poor glycaemic control that predicts progression of albuminuria in type 2 diabetes mellitus: A 3-year longitudinal cohort study.

AIMS: Poor glycaemic control elevates the risk for vascular complications. Biomarkers for predicting susceptibility to glycaemic worsening are lacking. This 3-year prospective analysis assessed the utility of several circulating diabetes-related biomarkers for predicting loss of glycaemic control, and their contribution to albuminuria progression in type 2 diabetes mellitus (T2DM). METHODS: T2DM subjects with adequately-controlled diabetes (HbA1c < 8%) at initial recruitment were analysed (N = 859). Baseline plasma levels of osteoprotegerin (OPG), C-reactive protein (CRP), adiponectin, intercellular-cell adhesion molecule-1, and vascular-cell adhesion molecule-1 were quantified using immunoassay. Definitions for development of uncontrolled diabetes and albuminuria progression were HbA1c ≥ 8.0% and increase in albuminuria category at follow-up, respectively. RESULTS: At follow-up, 185 subjects developed uncontrolled diabetes. Higher baseline CRP and OPG levels were observed in the high-risk individuals, and predicted increased risk for developing uncontrolled diabetes. OPG, but not CRP, was associated with albuminuria progression after multivariable adjustment. The relationship was attenuated following adjustment for development of uncontrolled diabetes, which emerged as a significant associate. Mediation analysis revealed that loss of glycaemic control explained 64.5% of the relationship between OPG and albuminuria progression. CONCLUSIONS: OPG outperformed other diabetes-related biomarkers to be a potentially useful biomarker for predicting loss of glycaemic control and its associated albuminuria deterioration.

Endothelin-1 predicts incident diabetic peripheral neuropathy in Type 2 Diabetes: a cohort study.

INTRODUCTION: Diabetic peripheral neuropathy (DPN) is a common microvascular complication in patients with type 2 diabetes (T2D). Apart from hyperglycemia, few modifiable risk factors have been identified. Endothelin-1 is a potent vasoconstrictor peptide, implicated in the causal pathway of microangiopathy. We investigated whether baseline plasma endothelin-1 and other metabolic and vascular risk factors predicted the incidence of DPN. DESIGN: This is a 3-year observational, cohort study. METHODS: In patients with T2D (n = 2057), anthropometric data, fasting blood, and urine were collected for biochemistry and urine albumin/creatinine measurements. Forearm cutaneous endothelial reactivity was assessed by iontophoresis and laser Doppler flowmetry/imaging. Measurements were repeated on follow-up. Incident DPN was considered present if an abnormal finding in monofilament (<8 of 10 points) or neurothesiometer testing was ≥25 volts on either foot at 3-year follow-up, but normal at baseline. Plasma endothelin-1 was assessed by ELISA. RESULTS: At baseline, mean age of patients was 57.4 ± 10.8 years old and prevalence of DPN was 10.8%. Of the 1767 patients without DPN, 1250 patients returned for follow-up assessment ((2.9 ± 0.7) years), with a 10.7% incidence of DPN. Patients with incident DPN had significantly higher baseline endothelin-1 (1.43 (1.19-1.73) vs 1.30 (1.06-1.63)) pg/mL, P < 0.0001. Multivariable Cox proportional hazards ratio showed a 1-s.d. increase in log endothelin-1 (adjusted HR: 4.345 (1.451-13.009), P = 0.009), systolic blood pressure (per 10-unit) (adjusted HR: 1.107 (1.001-1.223), P = 0.047) and diabetes duration (adjusted HR: 1.025 (1.004-1.047), P = 0.017) predicted incident DPN, after adjustment for glycemic control, eGFR, albuminuria, peripheral arterial disease and retinopathy status. CONCLUSION: Higher baseline endothelin-1, blood pressure and diabetes duration were significant and independent predictors for incident DPN. Validation of our findings in independent cohorts and molecular mechanistic studies will help better our understanding on the role of endothelin-1 in DPN.

Role of endothelium-independent vasodilation in the relationship between visceral adiposity and reduced cognitive performance in older adults with type 2 diabetes.

OBJECTIVE: In this cross-sectional analysis, we sought to assess the relationship of adiposity and forearm microvascular reactivity with cognitive dysfunction among older Asians with type 2 diabetes (T2D). METHODS: Subjects with T2D aged ≥ 55 years were analyzed (N = 907). Cognitive performance was assessed using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and Mini-Mental State Exam (MMSE). Visceral fat area (VFA) was estimated by tetrapolar multi-frequency bioimpedance. Forearm microvascular endothelium-dependent vasodilation (EDV) and endothelium-independent vasodilation (EIV) were assessed by laser Doppler imaging with iontophoresis. RESULTS: RBANS total score was correlated with VFA, EDV, and EIV (all P < .05). However, VFA was correlated with EIV, but not with EDV. Multivariable linear regression showed significant association between VFA and RBANS total score (B = -0.02, 95% CI= -0.03 to -0.01) or memory (immediate and delayed) index scores. These associations were attenuated after adjustment for EIV. Mediation analysis showed that EIV partially mediated the relationship between visceral adiposity and RBANS scores (all Sobel tests P < .05). EIV also mediated the relationship between VFA and MMSE score. CONCLUSIONS: Impaired endothelium-independent vascular smooth muscle reactivity may exert a mediatory effect on the association between increased visceral adiposity and decreased cognitive performance in older adults with T2D.

Association between gain in adiposity and diabetic kidney disease worsening in type 2 diabetes is mediated by deteriorating glycaemic control: A 3-year follow-up analysis.

AIMS: Increased adiposity confers elevated risk for diabetic kidney disease (DKD) progression in type 2 diabetes mellitus (T2DM). This 3-year prospective study examined whether worsening of metabolic control e.g. development of uncontrolled diabetes mediated the relationship between increased adiposity and DKD deterioration. METHODS: T2DM subjects who had adequately controlled diabetes (HbA1c < 8%) at initial recruitment were analysed (N = 853). HbA1c ≥ 8% at follow-up was classified as development of uncontrolled T2DM. Absolute changes in body weight (ΔWeight), body mass index (ΔBMI), and body fat mass (ΔBFM) were calculated by subtracting baseline from follow-up values. DKD deterioration (outcome) was defined as an increase in the composite ranking of relative risk by glomerular filtration rate and albuminuria levels (Kidney Disease: Improving Global Outcomes 2009). RESULTS: Subjects with deteriorated DKD displayed lower reduction in body composition at follow-up than those who remained stable or/improved (all P < 0.05). In separate regression models, ΔWeight (risk ratio (RR):1.04, 95% CI:1.01-1.06), ΔBMI (RR:1.07, 95% CI:1.01-1.13), and ΔBFM (RR:1.03, 95% CI:1.01-1.06) were independently associated with worsened DKD. The associations were attenuated after accounting for the loss of glycaemic control. Binary mediation analysis revealed that the development of uncontrolled diabetes explained 41.7%, 45.4% and 39.7%, respectively, of the effects of ΔWeight, ΔBMI and ΔBFM on the outcome. CONCLUSIONS: Among T2DM individuals who had adequately-controlled T2DM at initial recruitment, the relationship between gain in adiposity and DKD deterioration is mediated by the development of poor glycaemic control over time. Therefore, preventing worsening adiposity and hyperglycaemia is pivotal to impede DKD progression.

Gain in adiposity over 3 years is associated with progressive renal decline in multi-ethnic South-east Asians with type 2 diabetes.

BACKGROUND: This study evaluated the association between gain in adiposity and renal decline in a large prospective multiethnic South-east Asian cohort with type 2 diabetes mellitus (T2DM). METHODS: Three years after the baseline visit, 2057 T2DM subjects were recalled for reassessment. The final cohort comprised 1014 subjects and was categorized into tertiles based on changes in body weight (ΔWt), body mass index (ΔBMI), visceral fat area (ΔVFA), and BMI-adjusted VFA (ΔVFABMI ). Outcomes included annual and rapid (≥3 mL/min per 1.73 m2 per year) decline in estimated glomerular filtration rate (eGFR) and progression of albuminuria. RESULTS: Participants (mean [±SD] age 57 ± 11 years, 48.8% women, BMI 27.7 ± 5.4 kg/m2 ) exhibited a median annual decline in eGFR of 1.0 mL/min per 1.73 m2 . Compared with the lower tertiles, Tertile 3 of ΔWt, ΔBMI, ΔVFA, and ΔVFABMI had the highest anthropometric increase, albeit of modest magnitude, and this was accompanied by the worst renal outcomes (all P < 0.05). The relationship between annual eGFR decline and Tertile 3 of ΔWt, ΔBMI, and ΔVFABMI persisted after multivariate adjustment in men but not in women. In addition, Tertile 3 of ΔWt, ΔBMI, ΔVFA, and ΔVFABMI predicted rapid eGFR decline. Anthropometric gains were also associated with progression of albuminuria. CONCLUSIONS: Modest longitudinal gain in adiposity was associated with progressive renal decline in T2DM patients, suggesting that increased adiposity over time adversely affects renal outcomes. Therefore, a carefully designed weight-neutral or -loss antidiabetic treatment regimen is important when managing T2DM in the clinic.

The association of serum creatinine and estimated glomerular filtration rate variability with diabetic retinopathy in Asians with type 2 diabetes: A nested case-control study.

BACKGROUND: Fluctuation of kidney function may signify intra-glomerular microvascular hemodynamic instability. We aim to examine the association of long-term serum creatinine and estimated glomerular filtration rate variability with diabetic retinopathy. METHODS: We included type 2 diabetes mellitus patients who attended the Diabetes Centre in 2011-2014 and were followed up (median = 3.2 years). Digital colour fundus photographs were assessed for diabetic retinopathy at follow-up. Diabetic retinopathy severity was categorized into non-proliferative diabetic retinopathy and proliferative diabetic retinopathy. We conducted a nested case-control study involving 177 diabetic retinopathy (118 non-proliferative diabetic retinopathy, 50 proliferative diabetic retinopathy) and 327 age- and gender-matched non-diabetic retinopathy. Serum creatinine measured before follow-up visit was obtained (⩾3 readings/patient). Variability was calculated as intra-individual standard deviation/√ n/( n - 1). RESULTS: Diabetic retinopathy have higher adjusted-serum creatinine-standard deviation than non-diabetic retinopathy [9.1 (4.9-21.6) vs 5.4 (3.4-10.1) µM, p < 0.001]. After multivariable adjustment, adjusted-serum creatinine-standard deviation was associated with diabetic retinopathy [odds ratio = 1.47, 95% confidence interval (1.02-2.10), p = 0.04]. The area under the curve increased significantly after adding adjusted-serum creatinine-standard deviation [0.70 (0.65-0.75) vs 0.72 (0.68-0.77), p < 0.03]. Proliferative diabetic retinopathy have higher adjusted-serum creatinine-standard deviation than non-proliferative diabetic retinopathy [15.5 (6.6-39.7) vs 7.47 (4.52-17.8) µM, p < 0.001]. After adjustment, adjusted-serum creatinine-standard deviation remained associated with non-proliferative diabetic retinopathy [1.48 (1.04-2.12), p = 0.03] and proliferative diabetic retinopathy [2.43 (1.34-4.39), p = 0.003; p-trend = 0.002]. Similar findings were observed for estimated glomerular filtration rate variability. CONCLUSION: Serum creatinine and estimated glomerular filtration rate variability is associated with the presence and severity of diabetic retinopathy independent of intra-individual means. This may inform novel therapeutic strategies aiming to achieve stable renal function in type 2 diabetes mellitus.

Long-term prospective observation suggests that glomerular hyperfiltration is associated with rapid decline in renal filtration function: A multiethnic study.

AIM: Glomerular hyperfiltration usually occurs early in development of kidney complications in diabetes. To understand hyperfiltration as a marker of renal disease progression in type 2 diabetes mellitus, we aimed to examine association between glomerular hyperfiltration (estimated glomerular filtration rate ⩾ 120 mL/min/1.73 m2) and rapid renal decline (annual estimated glomerular filtration rate loss ⩾ 3 mL/min/1.73 m2). METHODS: This was a prospective cohort comprising 1014 patients with type 2 diabetes mellitus attending a Diabetes Centre of a regional hospital in 2002-2014. A separate prospective cohort, comprising 491 patients who attended Diabetes Centre or primary-care polyclinics, was used for validation. We performed binary mediation analysis to examine role of hyperfiltration on relationship between baseline haemoglobin A1c and rapid renal decline. RESULTS: Among patients in discovery cohort, 5.2% had baseline hyperfiltration. Over mean follow-up of 6 years, 22.9% had rapid glomerular filtration rate decline. Baseline hyperfiltration was significantly associated with greater odds of rapid renal decline after adjusting for demographics, diabetes duration and clinical covariates (odds ratio: 2.57; 95% confidence interval: 1.21-5.46; p = 0.014). Similar finding was found in validation cohort (odds ratio: 2.98; 95% confidence interval: 1.06-8.42; p = 0.034). Hyperfiltration significantly accounted for 35.3% of association between increasing baseline haemoglobin A1c and rapid renal decline. CONCLUSION: Glomerular hyperfiltration is an independent risk factor of rapid renal decline. It mediates the association between increasing haemoglobin A1c and rapid renal decline.