Steroid responsiveness and frequency of relapse in adult-onset minimal change nephrotic syndrome.

To clarify factors influencing the response to corticosteroids and subsequent relapses, 62 Japanese adult patients with minimal change nephrotic syndrome were analyzed retrospectively. Five patients experienced remission spontaneously. Fifty-three patients entered complete remission, 3 patients entered partial remission, and 1 patient showed no response to corticosteroids. Fifty-three patients with complete remission were divided into two groups: 38 early responders who experienced remission completely within 8 weeks after starting treatment and 15 late responders who experienced remission after 8 weeks. Blood urea nitrogen and serum creatinine levels and proteinuria selectivity index at presentation were significantly worse in late than early responders. Relative interstitial volume determined by the point-counting method was significantly greater in late than early responders. Relative interstitial volume showed significant correlations with blood urea nitrogen, serum creatinine, and proteinuria selectivity index values. Thirty-three patients experienced a relapse; 13 patients experienced multiple relapses. Fifty-three patients with remission were divided into three groups: 16 patients who experienced relapse within 6 months after the initial response (early relapsers), 17 patients who experienced relapse after 6 months (late relapsers), and 20 patients who did not experience relapse (nonrelapsers). Mean age at onset was younger in early relapsers than late or nonrelapsers. Age at onset correlated inversely with relapse rate in 53 patients with remission and correlated positively with timing of the first relapse in 33 relapsers. It thus was suggested that impaired renal function and poor selectivity of proteinuria, which might be related to interstitial edema, were factors influencing a slower response to corticosteroids. Younger patients had a greater incidence of relapse and were prone to experience relapse earlier.