OBJECTIVETo study the long-term outcome of idiopathic IgA nephropathy and analyze its clinical and histological prognostic factors.

METHODSWe conducted a retrospective analysis of 495 cases of IgA nephropathy patients in our hospital from 1986 to 2002. Renal survival was analyzed by Kaplan-Meier method, univariate analysis and multivariate Cox regression analysis.

RESULTSThe cumulative renal survival rate was 85% at 10 years and 70.9% at 15 years. Univariate analysis found the following parameters at the time of biopsy to be significantly correlated with poor renal survival: serum creatinine > or = 133 micromol/L (P < 0.001), hypertension (P < 0.05), 24-hour urine protein excretion > or = 3 g (P < 0.001), histological subclass V (P < 0.001), and without the history of gross hematuria (P < 0.05). The Cox regression analysis showed that only the presence of hypertension (HR=7.75, 95%CI 1.02 to approximately 2.19) and serum creatinine level (HR=1.49, 95%CI 1.54 to approximately 38.90) were independent prognostic indicators.

CONCLUSIONSThe findings in Chinese IgA nephropathy patients are in agreement with the results of many other studies worldwide.

Adolescent ; Adult ; Child ; Creatinine ; blood ; Female ; Glomerulonephritis, IGA ; complications ; pathology ; physiopathology ; Humans ; Kidney ; pathology ; physiopathology ; Male ; Middle Aged ; Prognosis ; Regression Analysis ; Renal Insufficiency ; etiology ; pathology ; physiopathology ; Retrospective Studies ; Treatment Outcome

BACKGROUND/AIMS: Tubulointerstitial injury plays an important role in the progression of immunoglobulin A nephropathy (IgAN), and neutrophil gelatinase-associated lipocalin (NGAL) is among the most sensitive tubular biomarkers. We investigated whether serum or urine NGAL predicts prognosis in patients with IgAN. METHODS: The present study enrolled patients with biopsy-proven IgAN from January 2005 to December 2010, whose serum and urine samples at the time of kidney biopsy were preserved by freezing. We retrospectively reviewed patient clinical data and followed patients until October 2012. Serum and urine NGAL levels were measured using an enzyme-linked immunosorbent assay kit. Renal progression was defined as an estimated glomerular filtration rate decline by > 50% or progression to end-stage renal disease. RESULTS: There were 121 patients enrolled in this study. During the median follow-up period of 41.49 months, renal progression was found in nine patients (7.4%). Serum or urine NGAL alone could not predict renal progression; however, when serum and urine NGAL levels were combined, belonging to the high NGAL group independently predicted renal progression (hazard ratio [HR], 5.56; 95% confidence interval [CI], 1.42 to 21.73; p = 0.014), along with tubular damage graded according to the Oxford classification as T2 (HR, 8.79; 95% CI, 2.01 to 38.51; p = 0.004). In addition, a Kaplan-Meier curve of renal survival showed significantly higher renal progression in patients in the high NGAL group (log rank, p = 0.004). CONCLUSIONS: In patients with IgAN, high serum and urine NGAL levels at the time of kidney biopsy predict renal progression.
Acute-Phase Proteins/*urine ; Adult ; Biomarkers/blood/urine ; Biopsy ; Chi-Square Distribution ; Disease Progression ; Enzyme-Linked Immunosorbent Assay ; Female ; Glomerular Filtration Rate ; Glomerulonephritis, IGA/*blood/complications/pathology/physiopathology/*urine ; Humans ; Kaplan-Meier Estimate ; Kidney/*metabolism/pathology/physiopathology ; Lipocalins/*blood/*urine ; Male ; Middle Aged ; Multivariate Analysis ; Predictive Value of Tests ; Prognosis ; Proportional Hazards Models ; Proto-Oncogene Proteins/*blood/*urine ; Retrospective Studies ; Risk Factors ; Young Adult

BACKGROUND/AIMS: Neutrophil gelatinase-associated lipocalin (NGAL) is a well-known biomarker of acute kidney injury. We evaluated the value of plasma NGAL (pNGAL) as an independent predictor of prognosis in immunoglobulin A nephropathy (IgAN). METHODS: In total, 91 patients with biopsy-proven IgAN at a single center were evaluated. pNGAL was measured using a commercial enzyme-linked immunosorbent assay kit (R&D Systems). Adverse renal outcome was defined as chronic kidney disease (CKD) stage 3 or above at the last follow-up. Pearson correlation coefficient and Cox regression were used for analyses. RESULTS: The mean age of all patients (male:female, 48:43) was 35 years (range, 18 to 77). pNGAL ranged between 21.68 and 446.40 ng/mL (median, 123.97) and showed a correlation with age (r = 0.332, p = 0.001), creatinine (r = 0.336, p = 0.001), estimated glomerular filtration rate (r = -0.397, p < 0.001), uric acid (r = 0.289, p = 0.006), and the protein-to-creatinine ratio (r = 0.288, p = 0.006). During a mean follow-up period of 37.6 months, 11 patients (12.1%) had CKD stage 3 or above. In a multivariate Cox regression model, hypertension (hazard ratio [HR], 8.779; 95% confidence interval [CI], 1.526 to 50.496; p = 0.015), proteinuria > 1 g/day (HR, 5.184; 95% CI, 1.124 to 23.921; p = 0.035), and pNGAL (HR, 1.012; 95% CI, 1.003 to 1.022; p = 0.013) were independent predictors associated with adverse renal outcome. CONCLUSIONS: pNGAL showed strong correlations with other clinical prognostic factors and was also an independent predictor of adverse renal outcome. We suggest pNGAL as a potential predictor for prognosis in IgAN, while further studies are needed to confirm the clinical value.
Acute-Phase Proteins ; Adolescent ; Adult ; Aged ; Biomarkers/blood ; Biopsy ; Chi-Square Distribution ; Creatinine/blood ; Disease Progression ; Enzyme-Linked Immunosorbent Assay ; Female ; Glomerular Filtration Rate ; Glomerulonephritis, IGA/*blood/complications/pathology/physiopathology ; Humans ; Kidney/*metabolism/pathology/physiopathology ; Linear Models ; Lipocalins/*blood ; Male ; Middle Aged ; Multivariate Analysis ; Predictive Value of Tests ; Prognosis ; Proportional Hazards Models ; Proto-Oncogene Proteins/*blood ; Renal Insufficiency, Chronic/blood/etiology ; Republic of Korea ; Retrospective Studies ; Risk Factors ; Time Factors ; Young Adult