Association of plasma ceramide with decline in kidney function in patients with type 2 diabetes.

Circulating ceramide levels are dysregulated in kidney disease. However, their associations with rapid decline in kidney function (RDKF) and end-stage kidney disease (ESKD) in patients with type 2 diabetes (T2D) are unknown. In this prospective study of 1746 T2D participants, we examined the association of plasma ceramide Cer16:0, Cer18:0, Cer24:0, and Cer24:1 with RDKF, defined as an estimated glomerular filtration rate (eGFR) decline of 5 ml/min/1.73 m2 per year or greater, and ESKD defined as eGFR <15/min/1.73 m2 for at least 3 months, on dialysis or renal death at follow-up. During a median follow-up period of 7.7 years, 197 patients experienced RDKF. Ceramide Cer24:0 (odds ratio [OR] = 0.71, 95% CI 0.56-0.90) and ratios Cer16:0/Cer24:0 (OR = 3.54 [1.70-7.35]), Cer18:0/Cer24:0 (OR = 1.89 [1.10-3.25]), and Cer24:1/Cer24:0 (OR = 4.01 [1.93-8.31]) significantly associated with RDKF in multivariable analysis; 124 patients developed ESKD. The ratios Cer16:0/Cer24:0 (hazard ratio [HR] = 3.10 [1.44-6.64]) and Cer24:1/Cer24:0 (HR = 4.66 [1.93-11.24]) significantly associated with a higher risk of ESKD. The Cer24:1/Cer24:0 ratio improved risk discrimination for ESKD beyond traditional risk factors by small but statistically significant margin (Harrell C-index difference: 0.01; P = 0.022). A high ceramide risk score also associated with RDKF (OR = 2.28 [1.26-4.13]) compared to lower risk score. In conclusion, specific ceramide levels and their ratios are associated with RDKF and conferred an increased risk of ESKD, independently of traditional risk factors, including baseline renal functions in patients with T2D.

Incident heart failure and the subsequent risk of progression to end stage kidney disease in individuals with type 2 diabetes.

BACKGROUND: Diabetic kidney disease is an established risk factor for heart failure. However, the impact of incident heart failure on the subsequent risk of renal failure has not been systematically assessed in diabetic population. We sought to study the risk of progression to end stage kidney disease (ESKD) after incident heart failure in Asian patients with type 2 diabetes. METHODS: In this prospective cohort study, 1985 outpatients with type 2 diabetes from a regional hospital and a primary care facility in Singapore were followed for a median of 8.6 (interquartile range 6.2-9.6) years. ESKD was defined as a composite of progression to sustained eGFR below 15 ml/min/1.73m2, maintenance dialysis or renal death, whichever occurred first. RESULTS: 180 incident heart failure events and 181 incident ESKD events were identified during follow-up. Of 181 ESKD events, 38 (21%) occurred after incident heart failure. Compared to those did not progress to ESKD after incident heart failure (n = 142), participants who progressed to ESKD after heart failure occurrence were younger, had higher HbA1c and higher urine albumin-to-creatinine ratio at baseline. The excess risk of ESKD manifested immediately after heart failure occurrence, persisted for two years and was moderated thereafter. Cox regression suggested that, compared to counterparts with no heart failure event, participants with heart failure occurrence had 9.6 (95% CI 5.0- 18.3) fold increased risk for incident ESKD after adjustment for baseline cardio-renal risk factors including eGFR and albuminuria. It appeared that heart failure with preserved ejection fraction had a higher risk for ESKD as compared to those with reduced ejection fraction (adjusted HR 13.7 [6.3-29.5] versus 6.5 [2.3-18.6]). CONCLUSION: Incident heart failure impinges a high risk for progression to ESKD in individuals with type 2 diabetes. Our data highlight the need for intensive surveillance of kidney function after incident heart failure, especially within the first two years after heart failure diagnosis.

Clinical variable-based cluster analysis identifies novel subgroups with a distinct genetic signature, lipidomic pattern and cardio-renal risks in Asian patients with recent-onset type 2 diabetes.

AIMS/HYPOTHESIS: We sought to subtype South East Asian patients with type 2 diabetes by de novo cluster analysis on clinical variables, and to determine whether the novel subgroups carry distinct genetic and lipidomic features as well as differential cardio-renal risks. METHODS: Analysis by k-means algorithm was performed in 687 participants with recent-onset diabetes in Singapore. Genetic risk for beta cell dysfunction was assessed by polygenic risk score. We used a discovery-validation approach for the lipidomics study. Risks for cardio-renal complications were studied by survival analysis. RESULTS: Cluster analysis identified three novel diabetic subgroups, i.e. mild obesity-related diabetes (MOD, 45%), mild age-related diabetes with insulin insufficiency (MARD-II, 36%) and severe insulin-resistant diabetes with relative insulin insufficiency (SIRD-RII, 19%). Compared with the MOD subgroup, MARD-II had a higher polygenic risk score for beta cell dysfunction. The SIRD-RII subgroup had higher levels of sphingolipids (ceramides and sphingomyelins) and glycerophospholipids (phosphatidylethanolamine and phosphatidylcholine), whereas the MARD-II subgroup had lower levels of sphingolipids and glycerophospholipids but higher levels of lysophosphatidylcholines. Over a median of 7.3 years follow-up, the SIRD-RII subgroup had the highest risks for incident heart failure and progressive kidney disease, while the MARD-II subgroup had moderately elevated risk for kidney disease progression. CONCLUSIONS/INTERPRETATION: Cluster analysis on clinical variables identified novel subgroups with distinct genetic, lipidomic signatures and varying cardio-renal risks in South East Asian participants with type 2 diabetes. Our study suggests that this easily actionable approach may be adapted in other ethnic populations to stratify the heterogeneous type 2 diabetes population for precision medicine.

Association of Plasma Leucine-Rich Alpha-2 Glycoprotein 1 (LRG1) with All-Cause and Cause-Specific Mortality in Individuals with Type 2 Diabetes.

BACKGROUND: Leucine-rich alpha-2 glycoprotein 1 (LRG1) is a circulating protein in the transforming growth factor-beta superfamily. We sought to study whether LRG1 might predict risk for all-cause and cause-specific mortality in individuals with type 2 diabetes. METHODS: 2012 outpatients with type 2 diabetes were followed for a median of 7.2 years and 188 death events were identified. Association of LRG1 with risk for mortality was assessed by multivariable Cox regression models. RESULTS: Participants with a higher concentration of LRG1 had an increased risk for all-cause mortality [HR (95% CI), 1.76 (1.03-3.01), 1.75 (1.03-2.98), and 4.37 (2.72-7.02) for quartiles 2, 3, and 4, respectively, compared to quartile 1]. The association remained significant after adjustment for known cardio-renal risk factors including estimated glomerular filtration rate and albuminuria [adjusted HR 2.76 (1.66-4.59), quartile 4 versus 1]. As a continuous variable, a 1-SD increment in LRG1 was associated with 1.34 (1.14-1.57)-fold adjusted risk for all-cause mortality. High plasma LRG1 was independently associated with mortality attributable to cardiovascular disease, infection, and renal diseases. Adding LRG1 into a clinical variable-based model improved discrimination (c statistics from 0.828 to 0.842, P = 0.006) and reclassification (net reclassification improvement 0.47, 95% CI 0.28-0.67) for prediction of 5-year all-cause mortality. CONCLUSION: Plasma LRG1 predicts risk for all-cause mortality and mortality attributable to cardiovascular disease, infection, and renal disease independent of known cardio-renal risk factors. It may be a potential novel biomarker to improve risk stratification in individuals with type 2 diabetes.

Aortic pulse wave velocity, central pulse pressure, augmentation index and chronic kidney disease progression in individuals with type 2 diabetes: a 3- year prospective study.

BACKGROUND: Pulse wave velocity (PWV), central pulse pressure and augmentation index are arterial stiffness- related hemodynamic parameters but their associations with renal outcome are still controversial. We hereby aim to study, 1) which hemodynamic parameter is independently associated with progressive chronic kidney disease (CKD), 2) the association of 3-year change in PWV with CKD progression and, 3) the additive predictive value of PWV for progressive CKD. METHODS: Carotid- femoral PWV, central pulse pressure and augmentation index were measured in 1444 participants with type 2 diabetes at baseline and 3 years apart. Progressive CKD was defined as confirmed eGFR decline 40% or greater. RESULTS: In the follow-up, 102 participants experienced progressive CKD. All 3 hemodynamic parameters were significantly associated with progressive CKD In univariable analysis. However, only PWV remained statistically significant after adjustment for known clinical risk factors and the other 2 hemodynamic parameters (OR 1.14 [95% CI 1.01-1.29] per m/s increment). One m/s regression (decrement) in PWV in the 3-year follow-up was associated with 26% lower adjusted- risk of progressive CKD (OR 0.74, 95% CI 0.56-0.97). Adding PWV onto traditional risk factor- based model significantly improved classification (net reclassification improvement 0.25, 95% CI 0.05-0.45, P = 0.01) and positive prediction rate (24.5 to 32.3%). CONCLUSIONS: Of 3 arterial stiffness- related hemodynamic parameters, only PWV is independently associated with progressive CKD. PWV may be a potential intervention target to mitigate risk of CKD progression and also a biomarker to improve risk-stratification of adverse renal outcome in individuals with type 2 diabetes.

Plasma ceramides predict all-cause and cause-specific mortality in individuals with type 2 diabetes.

CONTEXT: The CERT1 (Cardiovascular Event Risk Test) score derived from plasma ceramides has been applied clinically for cardiovascular risk assessment. OBJECTIVE: To study whether plasma ceramides predict risk of mortality in patients with type 2 diabetes. DESIGN, SETTING AND PARTICIPANTS: A prospective study which included 1903 outpatients with type 2 diabetes in a regional hospital and a primary care facility in Singapore. EXPOSURE AND OUTCOME: Plasma ceramides (d18:1/16:0, d18:1/18:0, d18:1/24:0, d18:1/24:1) were measured by mass spectrometry and CERT1 score was calculated accordingly. Main outcomes were all-cause and cause-specific mortality. RESULTS: 252 death events were identified during median of 9.3 years of follow-up. Compared to those with low score (≤ 2), participants with a high CERT1 score (≥ 7) had 1.86 (95% CI 1.30-3.65) fold increased risk for all-cause death after adjustment for cardio-renal risk factors including eGFR and albuminuria. As continuous variable, one- unit increment in CERT1 was associated with 8% increased risk for all-cause death (adjusted HR 1.08 [1.04-1.13]). Adding CERT1 onto RECODe (Risk Equations for Complications Of type 2 Diabetes) mortality risk engine significantly improved prediction of 10- year risk of all-cause death (AUC 0.810 to 0.823, delta 0.013 [0.005-0.022]). The association between CERT1 and non-cardiovascular death remained significant (adjusted HR 2.12 [1.32-3.42]), whereas its association with cardiovascular death became non-significant after adjustment for kidney measurements (adjusted HR 1.41 [0.78-2.56]). CONCLUSION: CERT1 score predicts mortality risk independent of clinical cardio-renal risk factors. Further studies are warranted to elucidate the mechanistic linkage between ceramide and mortality, especially non-cardiovascular mortality.

Urine tricarboxylic acid cycle metabolites and risk of end stage kidney disease in patients with type 2 diabetes.

CONTEXT: Metabolites in tricarboxylic acid (TCA) pathway have pleiotropic functions. OBJECTIVE: To study the association between urine TCA cycle metabolites and the risk for chronic kidney disease (CKD) progression in individuals with type 2 diabetes. DESIGN, SETTING AND PARTICIPANTS: A prospective study in a discovery (n = 1826) and a validation (n = 1235) cohort of type 2 diabetes in a regional hospital and a primary care facility. EXPOSURE AND OUTCOME: Urine lactate, pyruvate, citrate, alpha-ketoglutarate, succinate, fumarate and malate were measured by mass spectrometry. CKD progression was defined as a composite of sustained eGFR below 15 ml/min/1.73 m2 , dialysis, renal death or doubling of serum creatinine. RESULTS: During a median of 9.2 (IQR 8.1-9.7) and 4.0 (3.2-5.1) years of follow-up, 213 and 107 renal events were identified. Cox regression suggested that urine lactate, fumarate and malate were associated with an increased risk (adjusted hazard ratio, aHR [95% CI] 1.63 [1.16-2.28], 1.82 [1.17-2.82] and 1.49 [1.05-2.11], per SD), while citrate was associated with a low risk (aHR 0.83 [0.72-0.96] per SD) for the renal outcome after adjustment for cardio-renal risk factors. These findings were reproducible in the validation cohort. Noteworthy, fumarate and citrate were independently associated with the renal outcome after additional adjustment for other metabolites. CONCLUSION: Urine fumarate and citrate predict the risk for progression to ESKD independent of clinical risk factors and other urine metabolites. These two metabolites in TCA cycle pathway may play important roles in the pathophysiological network underpinning progressive loss of kidney function in patients with type 2 diabetes.

Urine Leucine-Rich α-2 Glycoprotein 1 (LRG1) Predicts the Risk of Progression to End-Stage Kidney Disease in Patients With Type 2 Diabetes.

OBJECTIVE: Leucine-rich α-2 glycoprotein 1 (LRG1) was recently identified as an amplifier of transforming growth factor-ß (TGF-ß)-induced kidney fibrosis in animal models. We aimed to study whether urine LRG1 is associated with risk of progression to end-stage kidney disease (ESKD) in individuals with type 2 diabetes. RESEARCH DESIGN AND METHODS: A total of 1,837 participants with type 2 diabetes and estimated glomerular filtration rate (eGFR) >30 mL/min/1.73 m2 were recruited from a regional hospital and a primary care facility. Association of urine LRG1 with risk of ESKD (progression to sustained eGFR <15 mL/min/1.73 m2, dialysis, or death resulting from renal causes) was assessed by survival analyses. RESULTS: During a median follow-up of 8.6 (interquartile range 5.8-9.6) years, 134 incident ESKD events were identified. Compared with those in the lowest tertile, participants with baseline urine LRG1 in the highest tertile had a 1.91-fold (95% CI 1.04-3.50) increased risk of progression to ESKD, after adjustment for cardiorenal risk factors, including eGFR and albuminuria. As a continuous variable, 1 SD increment in urine LRG1 was associated with a 1.53-fold (95% CI 1.19-1.98) adjusted risk of ESKD. Of note, the association of urine LRG1 with ESKD was independent of plasma LRG1. Moreover, urine LRG1 was associated with rapid kidney function decline and progression to macroalbuminuria, two common pathways leading to ESKD. CONCLUSIONS: Urine LRG1, a TGF-ß signaling modulator, predicts risk of progression to ESKD independently of clinical risk factors in patients with type 2 diabetes, suggesting that it may be a novel factor involved in the pathophysiological pathway leading to kidney disease progression.

Plasma Tryptophan-Kynurenine Pathway Metabolites and Risk for Progression to End-Stage Kidney Disease in Patients With Type 2 Diabetes.

OBJECTIVE: We sought to study the associations between plasma metabolites in the tryptophan-kynurenine pathway and the risk of progression to end-stage kidney disease (ESKD) in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: Plasma tryptophan, kynurenine, 3-hydroxykynurenine, kynurenic acid, and xanthurenic acid concentrations were measured in discovery (n = 1,915) and replication (n = 346) cohorts. External validation was performed in Chronic Renal Insufficiency Cohort (CRIC) participants with diabetes (n = 1,312). The primary outcome was a composite of incident ESKD (progression to estimated glomerular filtration rate [eGFR] <15 mL/min/1.73 m2, sustained dialysis, or renal death). The secondary outcome was annual eGFR decline. RESULTS: In the discovery cohort, tryptophan was inversely associated with risk for ESKD, and kynurenine-to-tryptophan ratio (KTR) was positively associated with risk for ESKD after adjustment for clinical risk factors, including baseline eGFR and albuminuria (adjusted hazard ratios [HRs] 0.62 [95% CI 0.51, 0.75] and 1.48 [1.20, 1.84] per 1 SD). High levels of kynurenic acid and xanthurenic acid were associated with low risks of ESKD (0.74 [0.60, 0.91] and 0.74 [0.60, 0.91]). Consistently, high levels of tryptophan, kynurenic acid, and xanthurenic acid were independently associated with a slower eGFR decline, while a high KTR was predictive of a faster eGFR decline. Similar outcomes were obtained in the replication cohort. Furthermore, the inverse association between kynurenic acid and risk of ESKD was externally validated in CRIC participants with diabetes (adjusted HR 0.78 [0.65, 0.93]). CONCLUSIONS: Accelerated catabolism of tryptophan in the kynurenine pathway may be involved in progressive loss of kidney function. However, shunting the kynurenine pathway toward the kynurenic acid branch may potentially slow renal progression.

Risk of Incident Heart Failure in Individuals With Early-Onset Type 2 Diabetes.

CONTEXT: Early-onset diabetes has been associated with unfavorable cardiovascular risk but data on heart failure (HF) in this subpopulation are scarce. OBJECTIVE: We aimed to study the risk of, and risk factors for, incident HF in individuals with early-onset type 2 diabetes. METHODS: We studied 606 individuals with type 2 diabetes diagnosed before 40 years of age (early-onset) and 1258 counterparts with diabetes diagnosed from 41 to 65 years of age (usual-onset) with no HF history, at a regional hospital, over a median follow-up period of 7.1 years. Incident HF by European Cardiology Society criteria was determined. RESULTS: A total of 62 and 108 HF events were identified in the early- and usual-onset groups (1.55 and 1.29 per 100 patient-years), respectively. Compared with usual-onset counterparts, individuals with early-onset diabetes had a 1.20-fold unadjusted (95% CI, 0.88-1.63; P = 0.26) and 1.91-fold age-adjusted (95% CI, 1.37-2.66; P < 0.001) hazard ratio (HR) for incident HF. Adjustment for traditional cardiometabolic risk factors only moderately mitigated the hazards (adjusted HR 1.69; 95% CI, 1.19-2.40; P = 0.003). However, additional adjustment for estimated glomerular filtration rate and albuminuria markedly attenuated the association of early-onset age with incident HF (adjusted HR 1.24; 95% CI, 0.87-1.77; P = 0.24). Notably, a long diabetes duration was not significantly associated with HF risk after accounting for kidney measures. CONCLUSION: Individuals with early-onset diabetes have at least the same absolute risk and a 2-fold age-adjusted relative risk for incident HF. Excess cardiorenal risk factors but not a long diabetes duration are main drivers for HF development in this diabetic population.