Clinicopathological characteristics and prognostic factors of asymptomatic IgA nephropathy.

AIMS: Many patients with immunoglobulin class A (IgA) nephropathy (IgAN) present with asymptomatic urinary abnormalities. The purpose of this study was to observe the clinicopathological characteristics and prognostic factors in asymptomatic IgAN.

METHODS: Eighty-six asymptomatic IgAN patients (49 males and 37 females) were investigated; 82 of them were followed up during a mean +/- SD period of 66.7 +/- 19.7 months.

RESULTS: At biopsy, 18 patients (21%) presented with pure hematuria (HU), 29 patients (34%) presented with proteinuria alone (PU), and 39 patients (45%) presented concomitant hematuria and proteinuria with severe pathological lesions. Meanwhile, 16% and 26% had renal insufficiency and hypertension, respectively. Finally, urinary abnormalities of 15% of the patients disappeared, 25% of HU developed proteinuria, 47% of concomitant hematuria and proteinuria, and 32% of PU appeared to have increase of proteinuria, and 14% of PU developed hematuria. Fifteen (24%) of the patients with normal blood pressure initially became hypertensive and 18 (22%) of the patients with normal renal function initially developed renal insufficiency. Twenty-four patients (29%) had doubling of serum creatinine level, and 13 patients (16%) progressed to end-stage renal disease. Prednisone therapy and antihypertensive treatment significantly improved proteinuria and renal function deterioration. Hematuria, hypertension during follow-up, and tubulointerstitial lesions were independent risk factors predictive of the ultimate development of renal progression.

CONCLUSIONS: The renal outcome of asymptomatic IgAN is guarded. Hematuria, hypertension during follow-up, and tubulointerstitial lesions may be important markers to monitor renal progression in the course.