Poor Renal and Cardiovascular Outcomes in Patients with Biopsy-Proven Diabetic Nephropathy

Urine Matrix Metalloproteinase-7 (MMP-7) Versus Urine Albumin-to-Creatinine Ratio (ACR) as Predictors of Renal Dysfunction: A Decision Curve Analysis

BACKGROUND AND OBJECTIVES

The level of matrix metalloproteinase-7 (MMP-7) in diabetic urine samples escalates owing to reduced renal function. Renal biopsy is rarely recommended due to its invasive nature. Nowadays, urine albumin-to-creatinine ratio (ACR) is widely used to assess renal impairment. We mapped this study to compare urine MMP-7 and urine ACR as indicators of renal impairment.

METHODS

This cross-sectional study was conducted at Kalinga Institute of Medical Sciences (KIMS), Bhubaneswar, India, from February 2020 to January 2023. Adult patients with either type 2 diabetes mellitus (T2DM), kidney disease, or hypertension were scrutinized. Their serum creatinine, urine albumin, urine creatinine, urine ACR, and urine MMP-7 levels were evaluated. We correlated serum creatinine values with urine ACR and urine MMP-7 levels. For predictive modeling, we developed two models: ACR_model and MMP7_model. The ACR_model and MMP7_model weighed renal activity by analyzing participants with urine ACR > 30 mg/g and normalized urine MMP-7 > 10 µg/L, respectively. Each model's predictive accuracy was computed using the area under the receiver-operating characteristic (ROC) curve (AUC). For predictive modeling, we deployed the bootstrap method and decision curve analysis. We used R software (version 4.4.2) for data analysis.

RESULTS

A total of 287 (87.5%) of the 328 patients we scrutinized were deemed eligible for the study. We found statistically significant correlation coefficients of serum creatinine with urine MMP-7 than with urine ACR. It suggested a stronger association of serum creatinine with urine MMP-7. The study revealed that urine ACR had lower values of the following parameters than urine MMP-7: sensitivity (81.3% versus 86.7%), specificity (64.4% versus 68.2%), and diagnostic accuracy (78.2% versus 86.6%). The decision curve analysis unveiled that urine MMP-7 demonstrated higher net benefits juxtaposed with urine ACR, regardless of the threshold probability.

CONCLUSION

This study analyzed the role of urine ACR and urine MMP-7 as biomarkers of renal failure. We discovered stronger correlations between serum creatinine and urine MMP-7 contrasted with urine ACR. Urine MMP-7 offered better specificity, sensitivity, and diagnostic accuracy than urine ACR. The decision curve analysis also revealed that urine MMP-7 outperformed urine ACR in forecasting renal impairment.

Role of Urinary Matrix Metalloproteinase-7 (MMP-7) as an Early Marker of Renal Dysfunction in Diabetic Individuals: A Cross-Sectional Study

BACKGROUND AND OBJECTIVES

The matrix metalloproteinase 7 (MMP-7) level gets heightened in the urine samples of diabetic individuals with impaired renal function. Renal biopsy is seldom offered because of its invasive nature. These concerns spurred the investigation of relationships between urine MMP-7 levels and the renal function of diabetic individuals. Studies exploring this aspect are scarce. We aimed to evaluate the glycemic and renal parameters of female and male individuals with or without type 2 diabetes mellitus (T2DM) or kidney disease. We also assessed the correlation of urine MMP-7 with various parameters.

METHODS

This prospective, analytical, cross-sectional study was conducted at Kalinga Institute of Medical Sciences (KIMS), Bhubaneswar, India, from February 2020 to January 2023. Female and male individuals 18-85 years of age diagnosed with either T2DM, hypertension, or kidney disease were assessed for their glycemic indices and renal parameters. Those with both renal disease and T2DM were placed in group A. The diabetic individuals without kidney disease constituted group B. People in group C had neither kidney disease nor T2DM. Patients in group D had kidney disease but were not diabetics. The parameters of the male and female participants in each of the four groups were assessed and compared, including: age, body mass index (BMI), fasting blood sugar (FBS), glycosylated hemoglobin (HbA1c), serum urea, serum creatinine, estimated glomerular filtration rate (eGFR), urine albumin, urine creatinine, urine albumin-creatinine ratio (ACR), serum sodium, serum potassium, and urine MMP-7 levels. Furthermore, we correlated urine MMP-7 with all these traits. We used R software (version 4.4.0, Vienna, Austria) for data analysis.

RESULTS

Two hundred eighty-seven (87.5%) of the 328 individuals we screened were eligible. Of them, group A had the maximum number (94) of participants, followed by B (75), C (65), and D (53). Males comprised 60.3% (n = 173) of the study population. The median age of the participants was 52.0 (44.0-61.1) years. The intergroup variations were statistically significant (p < 0.001) owing to their glycemic status and renal function. The gender-basis comparison of FBS and HbA1c yielded non-significant differences. On the contrary, assessment of the renal parameters revealed significant differences (p < 0.001) between females and males. The study population had a median urine MMP-7 level of 19.9 (1.1-50.5) µg/L. Significant associations with urine MMP-7 were found with serum creatinine (r = 0.91, p < 0.001), urine ACR (r = 0.86, p < 0.001), and eGFR (r = -0.84, p < 0.001).

CONCLUSION

Our study portrayed that male diabetics, in comparison to female diabetics, had greater levels of urine ACR, urine MMP-7, eGFR, and serum creatinine. Moreover, urine ACR, eGFR, and serum creatinine strongly correlated with the urine MMP-7 level.

A comparative analysis of conventional and speckle-tracking strain echocardiographic findings in diabetic and non-diabetic kidney disease patients with normal ejection fraction

This study aimed to compare the differences in echocardiographic and strain parameters in patients with diabetic kidney disease (DKD) and non-diabetic kidney disease (NDKD) in a cohort with pre-dialysis chronic kidney disease (CKD) and normal ejection fraction (EF). In this single-center prospective study, patients with CKD stages 3-5 and EF > 55% were included. We compared cardiac structure and function using conventional and speckle-tracking strain echocardiography among DKD and NDKD groups. Cardiovascular outcomes were assessed at the end of the study. Of the included 117 patients, 56 (47.9%) had DKD, and 61 (52.1%) had NDKD. Patients with DKD had higher ratios of early mitral inflow velocity and mitral annular early diastolic velocity (E/e') (11.9 ± 4.4 vs. 9.8 ± 3.5; p = 0.004), lower septal e' velocity (7.1 ± 2.5 vs. 8.2 ± 2.8; p = 0.031), lower lateral e' velocity (9.2 ± 2.9 vs. 10.4 ± 3.8; p = 0.045) and longer deceleration times (209.2 ± 41.5 vs. 189.1 ± 48.0; p = 0.017), compared to those with NDKD. Left ventricular mass index (LVMI), global longitudinal strain (GLS), early diastolic strain rate (SR_E), and E/SR_E were similar. At a median follow-up of 239 days, 3-P MACE (11.5% vs. 4.9%; p = 0.047) and 4-P MACE (28.6% vs. 11.5%; p = 0.020) were observed to be higher in the DKD group. Diastolic dysfunction was more common in patients with DKD, compared to those with NDKD, although both groups had similar LVMI and GLS. Those with DKD also had poorer cardiovascular outcomes. This highlights the importance of the assessment of diastolic function in CKD, particularly in those with diabetic CKD.

Construction of a Prediction Model for the Mortality of Elderly Patients with Diabetic Nephropathy

To construct a prediction model for all-cause mortality in elderly diabetic nephropathy (DN) patients, in this cohort study, the data of 511 DN patients aged ≥65 years were collected and the participants were divided into the training set (n = 358) and the testing set (n = 153). The median survival time of all participants was 2 years. The data in the training set were grouped into the survival group (n = 203) or the death group (n = 155). Variables with P ≤ 0.1 between the two groups were selected as preliminary predictors and involved into the multivariable logistic regression model and the covariables were gradually adjusted. The receiver operator characteristic (ROC), Kolmogorov-Smirnov (KS), and calibration curves were plotted for evaluating the predictive performance of the model. Internal validation of the performance of the model was verified in the testing set. The predictive values of the model were also conducted in terms of people with different genders and ages or accompanied with chronic kidney disease (CKD) or cardiovascular diseases (CVD), respectively. In total, 216 (42.27%) elderly DN patients were dead within 2 years. The prediction model for the 2-year mortality of elderly patients with DN was established based on length of stay (LOS), temperature, heart rate, peripheral oxygen saturation (SpO₂), serum creatinine (Scr), red cell distribution width (RDW), the simplified acute physiology score-II (SAPS-II), hyperlipidemia, and the Chronic Kidney Disease Epidemiology Collaboration equation for estimated glomerular filtration rate (eGFR-CKD-EPI). The AUC of the model was 0.78 (95% CI: 0.73–0.83) in the training set and 0.72 (95% CI: 0.63–0.80) in the testing set. The AUC of the model was 0.78 (95% CI: 0.65–0.91) in females and 0.78 (95%CI: 0.68–0.88) in patients ≤75 years. The AUC of the model was 0.74 (95% CI: 0.64–0.84) in patients accompanied with CKD. The model had good predictive value for the mortality of elderly patients with DN within 2 years. In addition, the model showed good predictive values for female DN patients, DN patients ≤75 years, and DN patients accompanied with CKD.

Severe 25-Hydroxyvitamin D Deficiency May Predict Poor Renal Outcomes in Patients With Biopsy-Proven Diabetic Nephropathy

AIMS

This study aims to investigate the role of 25-hydroxyvitamin D (25(OH)D) levels in predicting renal survival in biopsy-proven diabetic nephropathy (DN) with type 2 diabetes mellitus (DM).

METHODS

In this retrospective study, a total of 161 biopsy-proven DN patients were enrolled and divided into four groups (normal group: 25(OH)D>20ng/ml; mild group: 10<25(OH)D ≤ 20ng/ml; moderate group: 5<25(OH)D ≤ 10 ng/ml; severe group: 25(OH)D ≤ 5 ng/ml). The effect of the 25(OH)D level on renal survival was evaluated by multivariate Cox regression.

RESULTS

A total of 161 type 2 DM patients with biopsy-proven DN were enrolled in this study. Patients with lower 25(OH)D levels had higher serum creatinine, urinary albumin creatinine ratio (UACR), total cholesterol, and parathyroid hormone levels as well as lower estimated glomerular filtration rate (eGFR), hemoglobin, albumin, and calcium levels and were more prone to diabetic retinopathy (DR). Rather than proteinuria and renal function, glomerular class and interstitial fibrosis and tubular atrophy (IFTA) had a significant correlation with 25(OH)D levels. Multivariate Cox regression indicated that severe deficiency of 25(OH)D levels was associated with adverse renal outcomes. Compared to the level in the normal group, after adjusting for clinicopathological characteristics, a lower 25(OH)D level remained a risk factor for renal outcomes. The HRs were 3.446 (95% CI 0.366-32.406, p=0.279) for the mild group, 8.009 (95% CI 0.791-81.102, p=0.078) for the moderate group, and 14.957(95%CI 1.364-163.995, P=0.027) for the severe group.

CONCLUSION

Levels of 25(OH)D less than 5 ng/ml were correlated with worse renal function, more pathological injury and poorer renal prognosis in patients with biopsy-proven DN.

Role of engulfment and cell motility 1 (ELMO1) gene polymorphism in development of diabetic kidney disease

Background

Diabetic kidney disease (DKD) is a progressive kidney disease that affects diabetic patients irrespective of glycemic state or hypertension. Therefore, early detection of DKD is of critical importance. Many genome-wide association studies have identified the engulfment and cell motility 1 (ELMO1) gene as a genetic marker linked to DKD. This study aimed to investigate the association between ELMO1 rs741301 gene polymorphism and the development of DKD among Egyptian patients with type 2 diabetes mellitus (T2DM). Allele and genotype frequencies were investigated in 304 subjects by real-time PCR allelic discrimination assay: 100 DKD patients, 102 diabetic patients without DKD, and 102 healthy controls.

Results

GG genotype of ELMO1 (rs741301) SNP and its allele frequencies were significantly high in all diabetic patients. GG genotype had an odds ratio (OR) of 6.095 and 95% confidence interval (CI) of 2.456–15.125, p < 0.001, while the frequent allele G had an OR of 2.366 and 95% CI of 1.450–3.859, p = 0.001. No significant difference was observed between T2DM without DKD and DKD.

Conclusion

Our results could not establish an association between the ELMO1 rs741301 variant and the progression of DKD.

Obstructive sleep apnea is associated with impaired renal function in patients with diabetic kidney disease

Obstructive sleep apnea (OSA) is a recognized risk factor for the development of diabetic kidney disease (DKD). Our objectives were to compare the urinary albumin-creatinine ratio (UACR) and estimated glomerular filtration rate (eGFR) of patients with DKD according to OSA severity, and to evaluate the contribution of sleep parameters to their renal function. In a multicenter, observational, cross-sectional study, 214 patients with DKD were recruited. After a sleep study, UACR and eGFR were measured, as well as serum creatinine, fasting glucose, glycated hemoglobin, insulin resistance, lipid profile and C-reactive protein. UACR was higher in severe OSA patients (920 ± 1053 mg/g) than in moderate (195 ± 232 mg/g, p < 0.001) or mild OSA/non-OSA subjects (119 ± 186 mg/g, p < 0.001). At the same time, eGFR showed an OSA severity-dependent reduction (48 ± 23 vs. 59 ± 21 vs. 73 ± 19 ml/min per 1.73 m², respectively; p < 0.001). Apnea-hypopnea index (AHI and desaturation index (ODI) were identified as independent predictors for UACR and eGFR, respectively. Therefore, in patients with DKD under optimized treatment, severe OSA is associated with a higher UACR and a lower eGFR, reflecting an additional contribution to the impairment of their renal function, although no causality can be inferred.

Neural tone and cardio-renal outcomes in patients with type 2 diabetes mellitus: a review of the literature with a focus on SGLT2 inhibitors

Recent clinical trials involving the systemic effects of sodium-glucose cotransporter 2 inhibitors (SGLT2i) have revealed beneficial outcomes pertaining to the microvascular sequelae of type 2 diabetes mellitus (T2DM) such as nephropathy, as well as macrovascular effects such as major adverse cardiovascular effects (MACE). Such findings have spurred the elevation of these agents to level A-tiers of recommendation within clinical guidelines addressing the management of complicated T2DM. While the mechanisms of SGLTi (-flozin drugs) are still being elucidated, a paucity of data exists within the literature appraising the role of neuromodulation and associated mechanisms in the aforementioned outcome studies. Given the role of the nervous system in orchestrating the pathologic processes that hamper cardio-renal status, insight into this topic offers an expanded perspective on T2DM. In this review we investigate the mechanisms by which SGLTi improve cardio-renal function in T2DM patients with emphases on neural tone and nervous system physiology.