Normoalbuminaemia is associated with IgA nephropathy in primary glomerulopathy with nephrotic-range proteinuria in Chinese patients

BACKGROUND: Massive proteinuria is often associated with hypoalbuminaemia in glomerulopathy. However, patients may have normal levels of serum albumin despite heavy proteinuria in many circumstances. This study analysed factors affecting serum levels of albumin in primary glomerulopathy patients with nephrotic-range proteinuria. METHODS: The renal histopathological data of 780 consecutive adult patients (age ≥ 18 years old) with primary glomerulopathy and nephrotic-range proteinuria, who received native renal biopsies in Peking University First Hospital from 1998 to 2007, were retrospectively analysed. RESULTS: Compared with patients with hypoalbuminaemia (serum albumin < 30 g/L), patients without hypoalbuminaemia were significantly younger (P < 0.001) and had significantly lower levels of proteinuria (P < 0.001). Patients without hypoalbuminaemia had a significantly higher proportion of IgA nephropathy (66.0% vs. 17.2%, P < 0.001). The independent predictors of hypoalbuminaemia in nephrotic-range proteinuria patients included age, gender, interval between onset of the disease and renal biopsy, proteinuria level, and pathological type of glomerulopathy. A serum level of albumin ≥ 35 g/L could predict IgA nephropathy with a specificity of 95.8%, and specificity increased with age. CONCLUSIONS: Among patients with primary glomerulopathy and nephrotic-range proteinuria, normoalbuminaemia is associated with IgA nephropathy.