RESUMO
BACKGROUND: Diabetic nephropathy is one of the most common complications associated with diabetes. However, non-diabetic kidney disease has been reported in patients with type 2 diabetes at varying incidence rates. The objective of our study is to investigate the occurrence, clinicopathological characteristics, and inflammatory markers linked to diabetic and non-diabetic nephropathy (NDN) in patients with type 2 diabetes mellitus (DM). Additionally, we aimed to explore the possibility of identifying non-diabetic pathology using different biopsy indications. MATERIALS AND METHODS: A total of 159 patients with type 2 DM who underwent renal biopsy at a tertiary care nephrology clinic between January 2000 and January 2022 were enrolled in the study. We collected comprehensive data, including patient demographics, co-morbidities, diabetes duration, renal biopsy indications and results, serological markers, renal function, diabetic retinopathy (DRP), full blood count, blood biochemistry, urinalysis, and inflammatory markers. Patients were categorized based on their biopsy indications, and their biopsy results were classified into three groups: isolated NDN, isolated diabetic nephropathy (DN), and mixed nephropathy with concurrent NDN. We evaluated the relationship between biopsy indications and accompanying pathologies and statistically assessed the likelihood of each biopsy indication detecting non-diabetic renal pathology. Additionally, differences in other data, including demographic and laboratory results and medical histories, among the three groups were investigated. RESULTS: The most frequent indication of renal biopsy was atypical presentations of nephrotic syndrome or nephrotic range proteinuria (ANS/ANP) in 25.1% of patients. Other indications included unexplained renal failure (URF) in 22.6%, atypical presentations of non-nephrotic range proteinuria (ANNP) in 18.2%, acute kidney injury or rapidly progressive kidney dysfunction (AKI/RPKD) in 16.9%, microscopic hematuria in 15.7%, URF with ANNP in 11.3%, and severe nephrotic range proteinuria (SNP) in 9.4%. Renal biopsy revealed isolated NDN in 64.8%, DN in 25.1%, and mixed nephropathy in 10.1% of patients. Primary glomerular diseases were the main non-diabetic renal pathology, predominantly focal segmental glomerulosclerosis (FSGS) (36.4%) followed by MN (10.6%) and IgA nephropathy (7.5%). In comparison with the isolated DN and mixed nephropathy groups, patients in the isolated NDN group had significantly shorter diabetes duration, fewer DRP, as well as lower serum creatinine and neutrophil-to-lymphocyte ratio (NLR). Multivariate logistic regression analysis revealed that presence of hematuria (OR 4.40; 95% CI 1.34 - 14.46, p = 0.014), acute nephrotic range proteinuria (OR 11.93; 95% CI 1.56 - 90.77, p = 0.017), and AKI/APKD (OR 41.08; 95% CI 3.40 - 495.39, p = 0.003) were strong predictors of NDN. Lower NLR (OR 0.77; 95% CI 0.60 - 0.98, p = 0.035), shorter duration of diabetes (OR 0.90; 95% CI 0.84 - 0.97, p = 0.010), and absence of DRP (OR 0.35; 95% CI 0.12 - 0.98, p = 0.046) were also found to be independent indicators of NDN. Receiver operating characteristic curve (ROC) analysis revealed a cut-off value of ≤ 3.01 for NLR (sensitivity of 63.1%, specificity of 63.5%) with regards to predicting non-diabetic renal pathology (p = 0.006). CONCLUSION: Renal biopsy findings in patients with type 2 DM highlight that the prevalence of NDN may be higher than assumed, as presented mainly in the form of primary glomerular disease. The presence of AKI/RPKD, hematuria, and ANS/ANP serves as a reliable indicator of non-diabetic renal pathology. In more ambiguous situations, factors such as a shorter duration of diabetes, absence of DRP, and a lower NLR value may assist clinicians in biopsy decision.
Assuntos
Injúria Renal Aguda , Diabetes Mellitus Tipo 2 , Nefropatias Diabéticas , Retinopatia Diabética , Nefropatias , Humanos , Nefropatias Diabéticas/diagnóstico , Nefropatias Diabéticas/epidemiologia , Nefropatias Diabéticas/etiologia , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/epidemiologia , Hematúria , Fatores de Risco , Rim/patologia , Nefropatias/patologia , Proteinúria/epidemiologia , Proteinúria/etiologia , Retinopatia Diabética/epidemiologia , Retinopatia Diabética/patologia , Biópsia/efeitos adversos , Estudos RetrospectivosRESUMO
OBJECTIVES: Progressive renal disease is characterized by histological changes in the kidney and fibrosis is a common outcome. Renal biopsy is the only diagnostic tool to evaluate these histopathological changes. Pentraxin-2 (PTX-2) is an anti-inflammatory constitutive plasma protein associated with the innate immune system. Recently, as a biomarker, the circulating level of PTX-2 is shown to be decreased in chronic fibrotic diseases. In this study, we aimed to investigate the relationship between renal fibrosis severity and serum PTX-2 levels in patients undergoing renal biopsy. METHODS: This cross-sectional study included 45 patients and 16 healthy individuals (HIs). The severity of renal fibrosis was evaluated according to the Banff and Sethi scoring systems by the same pathologist. PTX-2 was measured by an enzyme-linked immunosorbent assay and compared with the demographical, clinical, biochemical, and histopathological data of the patients and HIs. RESULTS: PTX-2 levels were lower in the biopsy group than in the HI group (p=0.12). Patients with moderate renal fibrosis had significantly lower serum PTX-2 levels than those in patients with minimal and mild fibrosis (p=0.017 and p=0.010, respectively). PTX-2 concentrations were correlated with serum albumin (r=0.30, p=0.016), and were negatively correlated with serum creatinine levels (rho=-0.42, p=0.01) and body mass index (r=-0.32, p=0.011). CONCLUSIONS: The results indicated that PTX-2 levels are significantly lower in patients with renal fibrosis than HIs, and declining further in patients with severe fibrosis.