Idiopathic minimal change nephrotic syndrome in older adults: steroid responsiveness and pattern of relapses

Minimal change nephrotic syndrome (MCNS) is a common form of nephrotic syndrome in children and young adults. We investigated its clinical presentations, steroid responsiveness, subsequent clinical course and patterns of relapse in older adults in whom it was diagnosed after the age of 50 years.

The clinical records of renal patients followed-up in a single out patient clinic were retrieved and those patients with biopsy-proven MCNS were included. Patients in the 18-50-year age range (Group A) at the time of biopsy were compared with those older than 50 years (Group B) with regard to baseline demographic data, clinical features and outcome of treatment.

In all, 50 patients were studied, 35 in Group A (age at diagnosis: 38.8+/-11.91 years) and 15 in Group B (age at diagnosis: 70+/-6.85 years), with an overall follow-up duration of 72.08+/-63.42 months. Group B had a higher prevalence of hypertension and lower creatinine clearance at presentation, but the values of creatinine clearance for both groups were comparable with age-matched controls. One patient from Group B and two from Group A had spontaneous remission. Complete remission was achieved in 9.09, 45.45, 90.91 and 100% of Group B patients and 15.63, 62.5, 87.5 and 93.75% of Group A patients after 2, 4, 8 and 16 weeks of steroid therapy, respectively. The median time to complete remission and the duration of steroid treatment were similar for both groups. From Group B five patients and 22 patients from Group A relapsed during follow-up (P=0.055), with similar proportions of each group being early relapsers or frequent relapsers. The average number of relapses was 2.06 episodes for Group A, compared with 0.87 episodes for group B (P=0.062). Second agents were used in 20 Group A and four Group B patients (P=0.048). Complications of treatment were more common in Group A. None of the patients developed doubling of serum creatinine during follow-up.

Clinical presentations of older patients with MCNS were similar to younger patients apart from the age-related decline of renal function and higher prevalence of hypertension. Both groups have similar steroid responsiveness, but older patients tend to have fewer relapses and require fewer second agents for treatment of relapses.