A retrospective cohort study of clinical characteristics and outcomes of type 2 diabetic patients with kidney disease

Background

Type 2 diabetes mellitus (T2DM) with chronic kidney disease (CKD) poses a serious health threat and becomes a new challenge. T2DM patients with CKD fall into three categories, diabetic nephropathy (DN), non-diabetic kidney disease (NDKD), and diabetic nephropathy plus non-diabetic kidney disease (DN + NDKD), according to kidney biopsy. The purpose of our study was to compare the clinical characteristics and kidney outcomes of DN, NDKD, and DN + NDKD patients.

Methods

Data on clinical characteristics, pathological findings, and prognosis were collected from June 2016 to July 2022 in patients with previously diagnosed T2DM and confirmed DN and or NDKD by kidney biopsy at Tongji Hospital in Wuhan, China. The endpoint was defined as kidney transplantation, dialysis, or a twofold increase in serum creatinine.

Results

In our 6-year retrospective cohort research, a total of 268 diabetic patients were admitted and categorized into three groups by kidney biopsy. The 268 patients were assigned to DN (n = 74), NDKD (n = 109), and DN + NDKD (n = 85) groups. The most frequent NDKD was membranous nephropathy (MN) (n = 45,41.28%). Hypertensive nephropathy was the most common subtype in the DN+NDKD group (n = 34,40%). A total of 34 patients (12.7%) reached the endpoint. The difference between the Kaplan-Meier survival curves of the DN, NDKD, and DN + NDKD groups was significant (p < 0.05). Multifactorial analysis showed that increased SBP [HR (95% CI): 1.018(1.002-1.035), p = 0.025], lower Hb [HR(95% CI): 0.979(0.961-0.997), p = 0.023], higher glycosylated hemoglobin [HR(95% CI): 1.338(1.080-1.658), p = 0.008] and reduced serum ALB [HR(95% CI): 0.952(0.910-0.996), p = 0.032] were risk factors for outcomes in the T2DM patients with CKD.

Conclusions

This research based on a Chinese cohort demonstrated that the risk of endpoint events differed among DN, NDKD, and DN+NDKD patients. In T2DM patients with CKD, DN patients displayed worse kidney prognosis than those with NDKD or DN + NDKD. Increased SBP, higher glycosylated hemoglobin, lower Hb, and decreased serum ALB may be correlated with adverse kidney outcomes in T2DM patients.

Global trends and focuses of GLP-1RA in renal disease: a bibliometric analysis and visualization from 2005 to 2022

Glucagon-like peptide 1 receptor agonist (GLP-1RA) is a new class of glucose-lowing agents with the kidney benefit effect. This paper aims at finding the current state and hotspots of the research on GLP-1RA in kidney disease by using bibliometric methodologies and visualization maps to analyze publications and provide the direction for future studies on that topic. Literature information was obtained by retrieving the WoSCC database. Then, software like Microsoft Excel, VOSviewer, and CiteSpace was used to analyze and process obtained data. Bibliometric analysis and visualization of nations, authors, organizations, journals, keywords, and references were also done by VOSviewer and CiteSpace. A total of 991 publications written by 4747 authors from 1637 organizations in 75 countries on GLP-1RA in renal disease in Web of Science Core Collection were retrieved. The number of publications and citations kept growing from 2015 to 2022. The USA, Univ Copenhagen, and Rossing Peter are the leading country, organization, and author on this topic, respectively. All literature was published in 346 journals, and DIABETES OBESITY & METABOLISM is the journal with the most contributions. Meanwhile, most references are from DIABETES CARE. "Cardiovascular outcome" is the most frequent keyword in the total publications, and the reference cited most times is "Liraglutide and Cardiovascular Outcomes in Type 2 Diabetes" by Marso SP. The topic of GLP-1RA in renal disease has attracted more and more attention all over the world. Existing studies are mainly about clinical use in patients with diabetes, and studies on the mechanism are lacking.

A Role for Sodium-Glucose Cotransporter 2 Inhibitors in the Treatment of Chronic Kidney Disease: A Mini Review

BACKGROUND

Sodium-glucose cotransport protein 2 (SGLT2) inhibitors, a new type of glucose-lowering drug, have been well proved in several clinical studies for their glucose-lowering and nephroprotective effects, and the nephroprotective effects include both indirect effects of metabolic improvement and direct effects, independent of glucose-lowering effects.

SUMMARY

In patients with diabetic kidney disease (DKD), several studies have demonstrated the potential nephroprotective mechanisms of SGLT2 inhibitors, and evidence of nephroprotective mechanisms in the non-DKD population is accumulating. Although the nephroprotective mechanism of SGLT2 inhibitors has not been fully elucidated, several laboratory studies have illustrated the mechanism underlying the effects of SGLT2 inhibitors at various aspects.

KEY MESSAGES

The purpose of this article is to review the mechanism of nephroprotective effect of SGLT2 inhibitors and to look forward to promising research in the future.

Triglyceride-glucose index is associated with the risk of chronic kidney disease progression in type 2 diabetes

OBJECTIVE

The study aimed to investigate the association of TyG index with chronic kidney disease (CKD) progression in type 2 diabetes mellitus (T2DM).

METHODS

A total of 179 T2DM patients with CKD were retrospectively included. CKD progression was defined as a doubling of baseline serum creatinine or onset of end-stage kidney disease (ESKD). Internal validation was performed by the Kidney Failure Risk Equation (KFRE) model and Net reclassification improvement (NRI).

RESULTS

The optimal cut-off value of the TyG index was 9.17. The cumulative incidence of kidney outcomes was significantly higher in the high-TyG group (v.s low-TyG group, P = 0.019). In addition, the high-TyG index was associated with a greater risk of CKD progression (HR 1.794, 95% CI 1.026-3.137, P = 0.040). And reclassification analyses confirmed the final adjusted model improved NRI (61.90% v.s model 2, 43.80% v.s model 1). The further RCS curves presented an inverted S-shaped relationship between the TyG index and the risk of CKD progression. Internal validation verified that a higher TyG index was associated with 2.10-fold increased odds of 2-year ESKD risk >10% (95% CI 1.82-8.21). Moreover, subgroup analysis suggested that the association was more pronounced in those at relatively early CKD stages (higher than stage 2) and with no medication history of oral hypoglycemic agents.

CONCLUSION

An elevated TyG index was associated with a higher risk of CKD progression in T2DM patients. Our findings suggested that timely targeting insulin sensitivity at the early stages of T2DM might be associated with declined future risk of CKD development.

Development and validation of a novel nomogram to predict diabetic kidney disease in patients with type 2 diabetic mellitus and proteinuric kidney disease

PURPOSE

Differentiating between diabetic kidney disease (DKD) and non-diabetic kidney disease (NDKD) in patients with Type 2 diabetes mellitus (T2DM) is important due to implications on treatment and prognosis. Clinical methods to accurately distinguish DKD from NDKD are lacking. We aimed to develop and validate a novel nomogram to predict DKD in patients with T2DM and proteinuric kidney disease to guide decision for kidney biopsy.

METHODS

A hundred and two patients with Type 2 Diabetes Mellitus (T2DM) who underwent kidney biopsy from 1st January 2007 to 31st December 2016 were analysed. Univariate and multivariate analyses were performed to identify predictive variables and construct a nomogram. The discriminative ability of the nomogram was assessed by calculating the area under the receiver operating characteristic curve (AUROC), while calibration was assessed using the Hosmer-Lemeshow goodness-of-fit test and calibration plot. Internal validation of the nomogram was assessed using bootstrap resampling.

RESULTS

Duration of T2DM, HbA1c, absence of hematuria, presence of diabetic retinopathy and absence of positive systemic biomarkers were found to be independent predictors of DKD in multivariate analysis and were represented as a nomogram. The nomogram showed excellent discrimination, with a bootstrap-corrected C statistic of 0.886 (95% CI 0.815-0.956). Both the calibration curve and the Hosmer-Lemeshow goodness-of-fit test (p = 0.242) showed high degree of agreement between the prediction and actual outcome, with the bootstrap bias-corrected curve similarly indicating excellent calibration.

CONCLUSIONS

A novel nomogram incorporating 5 clinical parameters is useful in predicting DKD in type 2 diabetes mellitus patients with proteinuric kidney disease.

Association between kidney biopsy findings in CKD patients with diabetes and renal replacement therapy initiation, a perspective from a low-middle income country

Kidney disease in diabetes mellitus is usually explained by diabetic kidney disease, but other superimposed etiologies occur frequently. The distinction between diabetic kidney disease and non-diabetic kidney disease can only be made by performing kidney biopsy. Our objective was to evaluate the association of diabetic kidney disease, non-diabetic kidney disease, or both with renal replacement therapy initiation. This is a retrospective cohort that included patients with type 2 diabetes mellitus for whom a kidney biopsy was indicated. Subjects were followed-up for 5 years, until renal replacement therapy initiation or were lost to follow up. One hundred and forty-one patients were included, 53 (39%) had diabetic kidney disease, 13 (9%) had non-diabetic kidney disease and 75 (54%) had both. Ninety-four percent of the cohort initiated renal replacement therapy during the 5-year follow-up. Higher degree of fibrosis was associated with a trend towards higher risk of requiring renal replacement therapy. In addition, the combined diabetic kidney disease + non-diabetic kidney disease group was associated with higher need of renal replacement therapy initiation when compared to the diabetic kidney disease group.

Association of urinary calcium and phosphorus excretion with renal disease progression in type 2 diabetes

OBJECTIVES

Diabetes is associated with a high incidence of microvascular disease, including nephropathy. The current study aimed to investigate the association of urinary calcium and phosphorus excretion with chronic kidney disease (CKD) progression in type 2 diabetes mellitus.

METHODS

A total of 159 T2DM patients with chronic kidney disease (CKD stage G1-G4) were retrospectively included. Patients were categorized into three groups according to the tertiles of 24-h urinary calcium and phosphorus excretion, respectively. Clinical parameters and laboratory findings were compared among the three groups. Cox proportional hazards models were used to estimate the associations of urinary calcium and phosphorus excretion with CKD progression and adjusted for baseline eGFR, urinary protein excretion, mean arterial pressure, and use of RAAS inhibitor. A cubic spline curve was used to explore the association between urinary calcium excretion and CKD progression, as well as urinary phosphorus excretion and CKD progression. Moreover, the subgroup effects of urinary calcium and phosphorus excretion on CKD progression were estimated using Cox regression. CKD progression was defined as double of baseline serum creatinine or occurrence of ESRD.

RESULTS

During a median of 18.23 months of follow-up, the composite renal outcomes were noted in 27%. Cumulative renal outcomes were significantly lower in the highest tertile of urinary calcium excretion and phosphorus excretion in Kaplan-Meier analyses. The multivariate Cox proportional hazards regression analyses indicated that both the highest tertile of urinary calcium and phosphorus excretion was associated with a lower risk for CKD progression compared with the lowest tertile. Restricted cubic spline analyses of the association between urinary calcium excretion and CKD progression indicated a linear association. Additionally, there was also a linear association between urinary phosphorus excretion and CKD progression. Subgroup analyses showed that higher urinary phosphorus excretion was particularly associated with a lower risk of CKD progression in non-diabetic kidney disease (NDKD) patients.

CONCLUSION

Higher urinary calcium and phosphorus excretion were associated with decreased risk of CKD progression in T2DM patients.

Non-diabetic glomerular lesions in diabetic kidney disease: clinical predictors and outcome in an Eastern European cohort

PURPOSE

Since patients' prognosis depends on the lesions identified by kidney biopsy (KB), we aimed to evaluate predictors of non-diabetic kidney disease (NDKD) in diabetic subjects and to assess their kidney outcome as compared to diabetic nephropathy (DN).

METHODS

180 adults diagnosed by KB with DN (n = 120) or NDKD (n = 60), over a 10 year time-span, were retrospectively included and followed for a mean of 48.1 (95% CI 43.1-53.1) months. Patients with superimposed specific lesions over DN and with steroid-induced diabetes were excluded. The primary endpoint was renal replacement therapy (RRT) initiation. Only subjects who were alive at the end of follow-up (73 with DN and 38 with NDKD) entered the kidney survival analysis.

RESULTS

Membranous nephropathy (9%) was the most common NDKD. Predictors for NDKD were shorter duration of diabetes (OR 0.88; 95% CI 0.81-0.96, p = 0.004), absence of diabetic retinopathy (OR 0.08; 95% CI 0.01-0.44, p = 0.003), and nephrotic syndrome at presentation (OR 3.55; 95% CI 1.39-9.04, p = 0.008). Subjects with NDKD needed RRT later as those with DN [82 (95% CI 67-97.1) vs. 45 (95% CI 34-56.5) months, p = 0.001]. In an adjusted Cox model, biopsy diagnosed DN independently predicted RRT (OR 4.43; 95% CI 1.54-12.7, p = 0.006). Other predictors were lower eGFR, higher proteinuria, and absence of renin-angiotensin inhibitor therapy.

CONCLUSION

As one-third of the investigated subjects had NDKD, and NDKD was associated with a better kidney survival, independently predicted by the type of glomerular lesion, KB appears the most reliable tool to guide therapy and to assess outcome in patients with diabetic kidney disease.

Association of diabetes with failure to achieve complete remission of idiopathic membranous nephropathy

PURPOSE

The association of type 2 diabetes with proteinuria remission and renal function decline in patients with idiopathic membranous nephropathy (IMN) remains elusive. This study was designed to assess such association.

METHODS

In this retrospective cohort study, we included 656 IMN patients treated with immunosuppressants or plus corticosteroids, of whom 72 were diagnosed as type 2 diabetes prior to or at diagnosis of IMN. Data on age, sex, body mass index, presence of hypertension and diabetes, laboratory tests, and therapeutic regimens were retrospectively retrieved from medical record. Cox regression was used to analyze risks of failure to achieve remission, relapse, and developing a ≥ 30% decline in estimated glomerular filtration rate (eGFR) or end-stage renal disease (ESRD) associated with baseline diabetes.

RESULTS

The patients were followed for 36.6 (IQR 17.5-59.0) months, of whom 451 reached complete remission, 92 achieved partial remission, and 61 developed a ≥ 30% eGFR decline or ESRD. IMN relapse occurred in 30.6% of the 543 remitted patients. Baseline diabetes was associated with failure to achieve complete remission (HR 0.61, 95% CI 0.43-0.86, P = 0.005) in patients with IMN, independently of age, sex, hypertension, baseline serum albumin, urine protein levels, and eGFR, and therapeutic regimens. However, we failed to identify independent association between baseline diabetes and failure to achieve total remission (HR  0.85, 95% CI 0.63-1.1, P = 0.29), IMN relapse (OR 0.92, 95% CI 0.49-1.7, P = 0.80), or ≥ 30% decline in eGFR or ESRD (HR  1.4, 95% CI 0.78-2.7, P = 0.24) in patients with IMN.

CONCLUSIONS

Baseline diabetes may be independently associated with failure to achieve complete remission, but not with IMN relapse and renal function decline in IMN patients.

Proposal of classification of "chronic kidney disease (CKD) with diabetes" in clinical setting

The natural history of typical and classical "diabetic nephropathy" has been described as high levels of albuminuria and subsequent renal function decline. However, recent decades, the cases, who show the reduced glomerular filtration rate (GFR) without the progression of albuminuria, has been increased. "Diabetic kidney disease (DKD)" is a concept that widely recognizes the pathophysiological change induced by diabetes as the onset and progressive factor of renal injury and renal function decline, regardless of the level of albuminuria. However, we may confuse that "chronic kidney disease (CKD) with diabetes" is "DKD". Therefore, to choose the appropriate treatment that should be prioritized in the clinical setting, we propose that "CKD with diabetes" is classified as "DKD", "non-DKD (NDKD) with diabetes" or "combined disease of DKD and NDKD".

Non-Diabetic Kidney Disease in Type 2 Diabetic Patients: Prevalence, Clinical Predictors and Outcomes

BACKGROUND/AIMS

Diabetic kidney disease (DKD) is one of the most frequent microvascular complications of diabetes and is the leading cause of end-stage kidney disease worldwide. In patients with diabetes, non-diabetic kidney disease (NDKD) can also occur. NDKD can be either alone or superimposed with the DKD. In this study, we aimed to investigate the utility of kidney biopsy in patients with type 2 diabetes mellitus (T2DM) and the predictability of diagnosing DKD versus NDKD from clinical and laboratory data. We also evaluated the prevalence and etiology of NDKD in patients with T2DM.

METHODS

We retrospectively reviewed type 2 diabetic patients who had kidney biopsy in the last 10 years for diagnosing possible NDKD in our center. In all patients kidney biopsies were performed because of atypical clinical features and biopsy samples were examined by light and immunofluorescence microscopy. Clinical parameters, laboratory workup and office blood pressures were recorded for each patient at the time of biopsy.

RESULTS

Eight patients were excluded due to missing data. A total of 48 patients (female/male: 26/22 and mean age: 59±8 years) were included in the study. According to the biopsy findings, 24 (50%) patients had NDKD alone, 20 (41.7%) had DKD alone and 4 (8.3%) had coexisting DKD and NDKD. The most common NDKD diagnoses were membranous nephropathy (29.2%), tubulointerstitial nephritis (20.8%) and IgA nephropathy (12.5%). There were no significant differences in three groups with respect to the duration of diabetes, proteinuria, hematuria and glycated hemoglobin A1c levels. Diabetic retinopathy (DR) was the most significant finding, which was associated with DKD. Positive and negative predictive values of DR for DKD were 88 and 81%, respectively.

CONCLUSION

This study demonstrated a high prevalence of NDKD in patients with T2DM. The absence of DR strongly predicted NDKD. Clinical decision alone can lead to wrong diagnosis and delay in appropriate therapy. Clinicians should consider the kidney biopsy more liberally when there is uncertainty on the exact etiology of the kidney disease. However, prospective multicenter studies are needed to clarify the prognosis and outcomes of patients with diabetics.