Long-term outcome of adult patients with minimal urinary abnormalities and normal renal function.

ABSTRACT

AIM: To define the long-term outcome of patients with minimal urinary abnormalities (defined by the presence of microscopic hematuria with no or less than 1 gm/day proteinuria), and normal renal function (defined by a serum creatinine < 1.3 mg/dl), we retrospectively studied patients who fulfilled the above criteria and had a kidney biopsy done before the year of 1992 (i.e. at least followed up for 5 years), with a definite pathological diagnosis. METHODS: A total of 41 cases among 719 cases of primary glomerulonephritis (5.7%) were enrolled into the study. There were 19 males and 22 females with a mean age of 35.4+/-14.7 years at biopsy. The duration of renal disease was 116.0+/-60.5 months and the duration of follow-up post biopsy was 100.2+/-38.1 months. The pathological diagnosis was IgA nephropathy (21 cases), focal glomerulosclerosis (9 cases), mesangial proliferative glomerulonephritis (8 cases), membranous glomerulonephritis (2 cases) and acute glomerulonephritis (1 case). RESULTS: At the end of follow-up, 8 cases (19.5%) had a certain degree of renal insufficiency including 2 (4.9%) in end-stage renal disease. The other cases were either in complete remission (6 cases) or stable condition (27 cases) with persistent microscopic hematuria and normal renal function. The long-term outcome was not correlated with any of the following parameters age, sex, disease duration, serum creatinine at presentation, daily protein loss at presentation, degree of glomerular change and degree of interstitial inflammatory cell infiltration. However, a poor long-term outcome was correlated with tubular atrophy (p < 0.05) and interstitial fibrosis (p < 0.05). CONCLUSION: We conclude that a minimal urinary abnormality with normal renal function at presentation does not necessarily imply a favorable long-term outcome in certain patients. Tubular atrophy and interstitial fibrosis but not glomerular change correlates with a worse prognosis. This further emphasizes the importance of renal biopsy in such cases.