Prognostic indicators of IgA nephropathy in the Chinese - Clinical and pathological perspectives
Li PKT., Ho KKL., Szeto CC., Yu L., Lai FMM.
Background. IgA nephropathy is the most common primary glomerulonephritis in the world. Up to 30% of patients can progress to end-stage renal disease (ESRD) in 10 years. Methods. We studied 168 Chinese patients with IgA nephropathy followed for an average of 7.4 years in our hospital and tried to identify the clinical and pathological data that were associated with the prognosis of the disease. Clinical features at the time of renal biopsy were reviewed. Severity of histological involvement was scored semi-quantitatively as grade 1-3. Results. There was a female preponderance in our cohort of patients (male:female ratio 1:1.5). The average age at biopsy was 32.9 ± 10.0 years. Forty-seven of the 168 patients (28.0%) were hypertensive and 47 of 136 patients (34.6%) had a family history of hypertension. A high histological grade of IgA nephropathy was associated with hypertension at presentation, family history of hypertension, a higher serum creatinine, total cholesterol and 24-h urine protein excretion, and a lower serum albumin level. During the follow-up period, four patients died and another 24 progressed to ESRD. The renal survival was 92.0% at 1 year, 87.5% at 5 years and 81.8% at 10 years. With univariate analysis, hypertension at presentation, family history of hypertension, renal impairment at presentation (plasma creatinine > 120 μmol/1), high cholesterol, proteinuria > 1 g day and high histological grading were associated with poor prognosis. With multivariate analysis, hypertension at presentation, family history of hypertension, renal impairment at presentation, proteinuria > 1 g/day and histological grading were independent predictors of renal survival. The relative risks of renal failure for patients were 9.60 (95% confidence interval 4.02-22.92) with hypertension, 1.56 (1.16-2.02) with a family history of hypertension, 15.38 (6.40-36.93) with renal impairment and 5.93 (3.07-11.46) with every increase of one histological grade. Male patients did not show a more adverse outcome compared with females. Conclusions. Our results suggest that renal biopsy remains useful, even in clinically trivial disease, because of its distinct value in prognosis and risk stratification. The long-term prognosis of IgA nephropathy in Chinese patients is guarded. The prognostic importance of family history of hypertension has not been widely recognized and requires further study.