Background: Rapidly progressive glomerulonephritis (RPGN) has been known to have a poor prognosis. Although evidence across adult RPGN cases has accumulated over many years, the number of case series in adolescents and young adults has been limited, requiring further studies.
Methods: A total of 1,766 cases from 1989 to 2007 were included in this nationwide questionnaire survey, led by Intractable (former name, Progressive) Renal Diseases Research, Research on intractable disease, from the Ministry of Health, Labour and Welfare of Japan. To elucidate age-related differences in 2-year patient and renal survival rates, the cases were divided into the following four groups: children (0-18 years), young adults (19-39 years), the middle-aged (40-64 years), and the elderly (over 65 years).
Results: Of the 1,766 total RPGN cases, antineutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis comprised 1,128 cases (63.9% of all RPGN cases), showing a tendency to increase with age. Two-year patient survival for RPGN was 93.9% among children, 92.6% in young adults, 83.2% in the middle-aged, and 68.8% in the elderly. The younger group (children plus young adults) showed a clearly higher survival rate compared to the older group (middle-aged plus elderly) (p<0.05). ANCA-associated glomerulonephritis also showed similar age-related results with all RPGN cases. The comparison of renal prognosis showed no statistically significant differences both in RPGN and in ANCA-associated GN.
Conclusion: The present study described the age-dependent characteristics of the classification of RPGN, especially focusing on a better prognosis of the younger group in patient survival both in RPGN and in ANCA-associated GN.