Frimat L, Briançon S, Hestin D, Aymard B, Renoult E, Huu T C, Kessler M
University Hospital, Nancy, France.
Nephrol Dial Transplant. 1997 Dec;12(12):2569-75. doi: 10.1093/ndt/12.12.2569.
As yet, no clinical or morphological prognostic classification of IgA nephropathy (IgAN) has been generally accepted. The objective of our study was to quantify the risk of developing end-stage renal failure (ESRF) in IgAN.
We report a prospective longitudinal study of 210 patients with IgAN confirmed by biopsy between 1987 and 1991. Thirty-two (15.2%) patients were lost to follow-up. Mean follow-up after renal biopsy was 5.6 (SD = 2.6) years. The variables included age, gender, illnesses prior to discovery of IgAN, clinical features at IgAN discovery, 24-h proteinuria, serum creatinine, IgA level, and antihypertensive drugs taken at the time of renal biopsy. Sixty-six renal biopsies were classified by light-microscopy according to Lee's morphological classification. The end-point was ESRF. Survival was analysed by a backward and forward stepwise procedure using the Cox model. The most accurate determination of relative risk was obtained by assessing collinearity of the variables.
Thirty-three patients (15.7%) (31 men) developed ESRF. The five univariately significant variables: gender, gross haematuria, 24-h proteinuria (24-P), serum creatinine (SC), and antihypertensive treatment, were candidates for multivariate analysis. The final model used SC (< or = 100, 100-150, > 150 mumol/l), 24-P (< 1, > or = 1 g/day) and gender (female vs male) as independent variables (relative risk and 95% confidence interval were 3.5 (2.1, 5.9) for SC; 5.1 (1.9, 13.6) for 24-P; and 3.5 (0.9, 15) for gender). These estimates were used to construct a prognostic classification of ERSF for men with IgAN: stage 1 (SC < or = 150 mumol/l and 24-P < 1 g/day), stage 2 ((SC > 150 mumol/l and 24-P < 1 g/day) or (SC < or = 150 mumol/l and 24-P > or = 1 g/day)); stage 3 (SC > 150 mumol/l and 24-P > or = 1 g/day). The ESRF-free survival was estimated with Kaplan-Meier analysis. It was 98.5% for stage 1, 86.6% for stage 2, 21.3% for stage 3 (P < 0.001), 7 years after histological diagnosis. The validity of Lee's prognostic classification was confirmed using an independent sample.
These classifications identify groups at high risk of ESRF. Therapeutic studies should focus on these groups.
迄今为止，IgA肾病（IgAN）尚无普遍接受的临床或形态学预后分类。我们研究的目的是量化IgAN患者发生终末期肾衰竭（ESRF）的风险。
我们报告了一项对1987年至1991年间经活检确诊的210例IgAN患者进行的前瞻性纵向研究。32例（15.2%）患者失访。肾活检后的平均随访时间为5.6（标准差=2.6）年。变量包括年龄、性别、发现IgAN之前的疾病、发现IgAN时的临床特征、24小时蛋白尿、血清肌酐、IgA水平以及肾活检时服用的降压药物。66例肾活检标本根据Lee形态学分类法进行光镜分类。终点为ESRF。使用Cox模型通过向后和向前逐步程序分析生存情况。通过评估变量的共线性获得相对风险的最准确测定。
33例患者（15.7%）（31例男性）发生ESRF。五个单变量显著的变量：性别、肉眼血尿、24小时蛋白尿（24-P）、血清肌酐（SC）和降压治疗，作为多变量分析的候选变量。最终模型使用SC（≤100、100 - 150、>150 μmol/L）、24-P（<1、≥1 g/天）和性别（女性与男性）作为自变量（相对风险和95%置信区间分别为：SC为3.5（2.1，5.9）；24-P为5.1（1.9，13.6）；性别为3.5（0.9，15））。这些估计值用于构建IgAN男性患者ESRF的预后分类：1期（SC≤150 μmol/L且24-P<1 g/天），2期（（SC>150 μmol/L且24-P<1 g/天）或（SC≤150 μmol/L且24-P≥1 g/天））；3期（SC>150 μmol/L且24-P≥1 g/天）。采用Kaplan-Meier分析估计无ESRF生存情况。组织学诊断7年后，1期为98.5%，2期为86.6%，3期为21.3%（P<0.001）。使用独立样本证实了Lee预后分类的有效性。
这些分类识别出了ESRF高风险组。治疗研究应关注这些组。
