Clinical And Prognostic Analysis Of Patients With Type 2 Diabetes Mellitus Complicated With Chronic Kidney Disease

ObjectiveTo evaluate the baseline clinical features and prognostic differences among patients with type 2 diabetes(T2DM)and biopsy-proven diabetic kidney disease(DKD),non-diabetic kidney disease(NDKD)and DKD mixed with NDKD,and to explore the predictive factors for NDKD as well as the independent predictors for adverse renal outcomes.Design and MethodsPatients with T2DM and chronic kidney disease(CKD)who underwent renal biopsy between January 2015 and December 2018 in the First Affiliated Hospital of Zhengzhou University were recruited in this prospective observational study.They were divided into three groups as diabetic kidney disease(DKD group),non-diabetic kidney disease(NDKD group)and DKD mixed with NDKD(MIX group)according to the pathological diagnosis.Baseline was defined as the time of renal biopsy.The general,clinical and pathological information at baseline were collected.Renal outcomes were defined as end-stage kidney disease(ESKD),a 40%decline of estimated glomerular filtration rate(eGFR),or all-cause mortality.Follow-up was performed until an endpoint event occurred or the end of the study(December 31,2020).A 1:1:1 matched case-control study was conducted,and the age difference at the time of renal biopsy was less than 5 years.Finally,105 cases(35 in each group)were selected for statistical analysis.Binary logistic regression analysis was used to analyze the independent predictors for NDKD in patients with T2DM and CKD.Cumulative renal survival for each group was estimated by the Kaplan-Meier method and compared by log-rank test.Cox regression analysis was used to analyze the hazard ratio(HR)and 95%confidence interval(95%CI)for renal outcomes.Two-sided P<0.05 was considered statistical significance.ResultsMean age of the 105 patients at baseline was(50.8±10.0)years,47(44.8%)were female and 58(55.2%)were male,the median duration of diabetes was 96(36,156)months,the median eGFR was 72.1(41.0,99.9)mL/min/1.73m2,and the urine protein excretion rate was 2.8(0.8,7.1)g/d.Diabetic retinopathy was present in 36(34.3%)patients.65(61.9%)patients had microscopic hematuria.The majority of patients(77,73.3%)had hypertension,47(44.8%)had anemia,and 46(43.8%)had severe proteinuria.When compared with NDKD group,the patients in DKD group had a significant longer duration of diabetes,higher incidence of diabetic retinopathy,higher levels of HbAlc,systolic blood pressure,blood urea nitrogen and 24-hour urinary protein excretion,as well as lower levels of hemoglobin and eGFR(all P<0.05).When it comes to the pathological types of NDKD,membranous nephropathy was the most common one,with a total of 24(34.29%)cases,followed by 18(25.71%)cases of IgA nephropathy.Membrane nephropathy was also the most common type in either NDKD group or MIX group,accounting for 13(37.14%)and 11(31.43%)cases,respectively.Binary logistic regression analysis showed that duration of diabetes<10 years(OR:4.281,95%CI:1.306-14.035,P=0.016),absence of diabetic retinopathy(OR:7.259,95%CI:2.174-24.239,P=0.001),and absence of anemia(OR:3.827,95%CI:1.205-12.161,P=0.023)were independent predictors for NDKD in patients with T2DM and CKD.During the median follow-up of 34 months,the endpoint events occurred in 43(41.0%)patients.The prognosis of NDKD group was significantly better than that of DKD group(log-rank χ2=9.932,P=0.002)and MIX group(log-rank χ2=6.232,P=0.013),while there was no significant difference in prognosis between MIX group and DKD group(log-rank χ2=0.105,P=0.746).Cox regression analysis showed that the presence of DKD(HR:3.555,95%CI:1.483-8.521,P=0.015)and anemia(HR:2.029,95%CI:1.099-3.746,P=0.043)were independent predictors of adverse renal outcomes in patients with T2DM and CKD.Higher glomerular classification(HR:1.564,95%CI:1.067-2.292,P=0.022),a family history of diabetes(HR:2.368,95%CI:1.106-5.071,P=0.027),and eGFR<60mL/min/1.73m2(HR:2.032,95%CI:1.006-4.107,P=0.048)at baseline were independent risk factors for renal events in patients with DKD.Conclusions1.The prognosis of DKD might be similar to DKD combined with NDKD,and both of them were worse than that of pure NDKD.2.Anemia is a poor prognosis predictor in patients with T2DM and CKD.Higher glomerular injury classification,a family history of diabetes,and lower eGFR correlate with higher risk of adverse renal outcomes in patients with diabetic kidney disease.