[Clinical and pathological manifestations of Chinese childhood patients with primary IgA nephropathy: a national collaborative study of 33 hospitals].

OBJECTIVE

Primary IgA nephropathy (IgAN) is characterized by a highly variable course ranging from a totally benign condition to rapidly progressive renal failure. About 30% of children with IgAN will eventually have end-stage renal failure after 20 years from onset. A nation-wide survey was conducted and data of hospitalized children (younger than 14 years old) with IgAN during the period of 1995 to 2004 were analyzed. The aim was to investigate the clinical and pathological characteristics, treatment and outcome of the hospitalized children with IgAN.

METHODS

Questionnaires concerning children with IgAN were designed by the Subspecialty Group of Nephrology, Chinese Society of Pediatrics and distributed to the doctors of 33 hospitals in China. The criterion of IgAN was prominent and diffuse IgA deposition and to a lesser extent, other immunoglobulins in the glomerular mesangium and/or capillary loops, and purpura nephritis, lupus nephritis and hepatic disease were excluded. The data were collected and analyzed.

RESULTS

From January 1, 1995 to December 31, 2004, 1349 hospitalized children were diagnosed as IgAN. The cases of childhood IgAN accounted for 1.37% of the hospitalized cases with urologic-kidney diseases and 11.18% of those who underwent renal biopsies. Complete records were available for 1203 patients. The male to female ratio was 2.07:1. Both the median ages at the disease onset and diagnosis were 9.0 years. The median duration from onset to diagnosis of IgAN was 4 months; 55.94% of patients had predisposing causes, especially infection. Recurrent macroscopic hematuria was the most common clinical manifestation (41.15%), followed by nephritic syndrome (23.77%) and hematuria and proteinuria (20.78%). Subclass III (41.40%) and II (28.51%) were the most common histologic types. The main type of immunofluorescence examination was IgA deposition (34.50%). The intensity of IgA deposition in patients with hematuria and proteinuria and in acute rapidly progressive nephritis was the strongest (+++). There was no unified treatment scheme. Some patients were treated with corticosteroids and immunosuppressants, and 69.24% of the patients with IgAN showed clinical improvement, 10.39% remained unchanged, and 2 cases presented deterioration. The rate of follow-up was 23.35%, the mean duration of follow-up was 24.4 months.

CONCLUSION

The mean age of onset of the primary childhood IgAN was after 6 years. Hematuria was the most common clinical manifestation. Subclass III and II were the most common histologic type. There was no unified treatment scheme. The rate of follow-up was lower and the rate of lost follow-up was high. It is necessary to establish a normalized management, treatment and follow-up system for childhood IgAN in China.