Spectrum In Elderly Patients With Renal Biopsy And Clinical Characters Of Elderly Patients With Idiopathic Membranous Nephropathy

Background and Objective:Trend of population aging in China is serious, prevalence of kidney disease in elderly population is high and it is important to clarify the spectrum in elderly renal kidney diseases. Pathological diagnosis by the renal biopsy is most useful, but the spectrum of elderly patients with kidney diseases in China is lack because they rarely take the renal biopsy, foreign data can’t substitute Chinese situation and domestic large-scale study is not much. On the other hand, although feature of spectrum in elderly patients with renal biopsy need to be studied, the consensus is that the Idiopathic Membranous Nephropathy (IMN) is most common, it need to be noticed mostly; clarify the differences between elderly and non-elderly patients with IMN is of positive significance. Based on the previous reasons, in this study we retrospective analysis clinical and pathological data of elderly patients with renal biopsy and patients with IMN, aims to clarify the spectrum of elderly patients with renal biopsy and the clinical and pathological differences between elderly and non-elderly patients with IMN.Methods:Subjects in the first part are elderly patients with renal biopsy in nephrology department from 2004 to 2013, clinical diagnosis include nephrotic syndrome (NS), chronic nephritic syndrome, rapidly progressive nephritic syndrome, tubulointerstitial nephropathy; renal function is divided into three types, chronic renal failure (CRF), acute kidney injury (AKI), normal renal function. We mainly analyzes the spectrum of clinical and pathological diagnosis, correspondence between clinical diagnosis and pathological diagnosis, renal function; especially analyze the corresponding pathological diagnosis in patients with AKI. Subjects in the second part are patients with IMN in nephrology department from 2004 to 2013, divided them into non-elderly, elderly according to age. We collected clinical characteristics which included age, sex, body mass index (BMI), blood pressure levels and the main laboratory examination, collected pathological indicators which included injury of glomeruli, tubular/interstitial, renal arterioles. We mainly analyzes the differences of clinical characteristics,pathological indicators between the two groups, furthermore, we analyzed the correlation between the clinical feature and pathological indicators. Statistical methods adopt t test, ANOVA, Kruskal-Wallis H method, χ2 test, Logistic regression analysis, SPSS 20.0 statistical software is used to handing all data.Result:796 elderly patients with renal biopsy were included, male to female ratio was 1.4:1, average age was 66.9 ± 5.4 years. The number of elderly patients with renal biopsy was increasing in the past decade, but the percentage in the hospitalized elderly patients with kidney disease did not show the same trend. Most common clinical diagnosis is NS (458 cases,57.53%) and chronic nephritic syndrome (287 cases, 36.05%), furthermore, the NS proportion gradually increased accompany with chronic nephritic syndrome proportion decreased. Primary glomerular disease is the main pathology diagnosis in elderly patients with renal biopsy(587 cases,73.7%),173 cases are secondary glomerular diseases, accounting for 21.73%. IMN is the first cause of primary glomerular disease and accounting for 44.63%, diabetic nephropathy is the first cause of secondary glomerular diseases and accounting for 24.28%, top three causes in all patients with renal biopsy are IMN (262 cases,32.91%), IgA nephropathy (130 cases, 16.33%), minimal change disease (MCD) is total of 68 cases, account for 8.54%. Furthermore, proportion of IMN gradually increased and the speed is increasing, too. IMN is the first cause of NS patients, IgA nephropathy is the first cause of chronic nephritic syndrome patients, ANCA-associated nephropathy is the first cause of rapidly progressive nephritic syndrome. MCD is also the first cause of AKI, and followed by ANCA-associated nephropathy.1058 IMN patients were included, male to female ratio are 1.3:1, age 47.38 ± 14.43 years old,, elderly group accounted for 21.17%, non-elderly accounted for 78.8%. Detection rate of IMN in elderly group is significantly more than non-eldery group; detection rate of IMN in both group gradually increased, but the constituent ratio of both group was relatively stable. Incidence of CRF were higher in elderly group than in non-elderly group. BMI, Hb, eGFR, Scr, serum phosphorus, IgG, IgA, Fib, urine osmotic pressure, blood pressure levels, the incidence of hypertension, type 2 diabetes, hematuria had significant difference among two groups, and is consistent with the natural tendency of aging. Alb and 24h urine protein have no significant differences, TCH, TG, LDL is significant less in the elderly group than in the non-elderly group.Global glomerular sclerosis score, incidence of global glomerular sclerosis, tubular atrophy/interstitial fibrosis score, incidence of hyaline degeneration in arterioles, incidence of intimal thickening in arterioles were significantly different between two groups, and is consistent with the natural tendency of aging, too. Independent associated factor of global glomerular sclerosis is hypertension in the elderly group, and are age, type 2 diabetes, MAP, Ua.163 elderly patients with IMN whose clinical manifestations is NS were included, age of 67.4 ±5.2 years,58 elderly patients with MCD were included, age of 66.9+5.9 years. The incidence of hematuria,24h urinary protein excretion, eGFR of IMN were significantly more than MCD, AKI incidence, Scr, C3, C4, Fib were significantly less than MCD. In this study, we try to established two identification equation to distingwish IMN and MCD. Equation I processed C3, C4, Fib as a continuous variable, haematuria (OR=0.24,95% C.I:0.11-0.56)、AKI (OR=21.44,95% C.I:6.65-69.12). Fib (OR=1.52,95% C.I:1.16-1.99) were discriminating clinical indicators, area of prediction probability under the ROC curve was 0.831. Equation Ⅱ detect best cutoff judgment value of C3, C4, Fib based on ROC mapping, and then make them into two categorical variables, haematuria (OR=0.28,95% C.I:0.12-0.66), AKI (OR=27.39,95% C.I:8.01-93.6)、C3≥115md/dl(OR=3.53,95% C.I:1.43-8.76),Fib>5.5g/L(OR=2.66, 95% C.I:1.14-6.19) were discriminating clinical indicators, area of prediction probability under the ROC curve was 0.843.Conclusion:Primary glomerular disease is the main pathology diagnosis in elderly patients with renal biopsy; IMN is the first cause of elderly patients with renal biopsy and NS, its proportion gradually increased; IgA nephropathy is the first cause of chronic nephritic syndrome patients, MCD is the first cause of AKI. More attentiones should be paided to diagnosis and treatment of elderly IMN patients, prevention and treatment of AKI in elderly MCD patients.Detective rate of IMN increased significantly in all patients, but not the charactors of elderly patients. Overall, differences of clinical and pathological indicator between elderly and non-elderly group are influenced by aging, and is consistent with the natural tendency of aging. Lipid levels of elderly patients with IMN whose clinical manifestation is NS does not exhibit a consistent change with aging, we should pay attention to protect the hepatic function in these patients. In order to prevent global glomeeular sclerosis became severe, non-elderly patients should be paid attention to control blood glucose, decrease blood pressure, blood uric acid level, elderly patients should be paid special attention to decrease blood pressure level.The incidence of hematuria, AKI are more and completment level is lower in elerly IMN patients with NS than in the MCD. This study proposes identification equation to distinguish the elderly IMN and MCD, can provide a help for diagnosis in elderly patients with NS.