Clinical features and natural history in adults with IgA nephropathy

Two different clinical syndromes might be observed at presentation in most patients with IgA nephropathy (IgAN): (1) an acute reversible episode of macroscopic hematuria or (2) asymptomatic urinary abnormalities. Patients in these groups differ by genetic markers, the severity of their histologic lesions, and the rate of progression to renal insufficiency. Macroscopic hematuria is more common in children, and its frequency decreases with increasing age. In our experience, most patients presenting in adulthood with macroscopic hematuria did not have proteinuria or microscopic hematuria prior to the episode of macroscopic hematuria, suggesting the onset of disease was indeed in adulthood. IgAN is not a benign disease. About 20% of patients reach end-stage renal failure after 20 years of clinical disease. Features generally associated with a poor prognosis include older age at onset, no history of recurrent macroscopic hematuria, hypertension, and consistent proteinuria. In some studies, men progressed more rapidly than women. Using the regression of Cox in the present study, the magnitude of proteinuria was the only clinical parameter that independently predicted progressive renal impairment.