Clinical course and prognostic factors of clinical early IgA nephropathy

Abstract

Background: Immunoglobulin A nephropathy (IgAN) is prevalent in many countries including China. At the time of diagnosis many IgAN patients present with normal renal function, proteinuria of 0.4 g/d or less, and normal blood pressure and they are classified as clinically early IgAN patients. However, the natural history of clinically early IgAN and prognostic factors has not yet been clarified.

Methods: We investigated 177 early IgAN patients (108 males and 69 females) followed up for a mean period of 111 +/- 43 months.

Results: During the follow-up period among 177 clinically early IgAN patients, urinary abnormalities disappeared in 9% of the patients; increased proteinuria was present in 79 patients (46%). The prevalence of hypertension was 38% (68 patients), and 24% (43 patients) developed renal insufficiency. Poor renal outcome was associated with haematuria, urinary protein excretion index (UPEI, the product of urinary protein excretion at the time of renal biopsy and prebiopsy duration), and tubulointerstitial lesions.

Conclusion: Renal outcome is dismal in patients with clinically early IgAN. Haematuria, UPEI, and tubulointerstitial lesions could be useful markers of a progressive course.