Urinary Protein-to-creatinine Ratios Predict Recurrence in Pediatric and Young Adult Cases of Minimal Change Nephrotic Syndrome.

High-dose steroids are required for the treatment of minimal change nephrotic syndrome (MCNS), especially for episodes of recurrence. Predicting and avoiding recurrence can help reduce the steroid dose, but prediction is currently difficult. We herein examined whether changes in laboratory data, especially the urinary protein- to-creatinine ratio (UTP/UCr), can predict clinical recurrence. We also assessed differences in clinical features between children and young adults. We included 36 patients with MCNS; for each case, we retrospectively studied laboratory data during stable remission and pre-recurrence, with the "stable" period defined as all but the 6 weeks before recurrence, and pre-recurrence defined as the 4±2 weeks before recurrence. UTP/UCr, serum albumin, etc. were measured every 5 years during stable periods. We divided patients into cohorts by age at recurrence, < 15 years and ≥ 15 years, and compared stable and pre-recurrence values for the two groups. UTP/UCr values during stable periods tended to be higher in younger patients. UTP/UCr and serum albumin showed statistically significant changes during pre-recurrence periods, but only in those aged ≥ 15 years. Thus, clinical features of recurrence differed depending on age. Signs of recurrence can be confirmed via UTP/UCr or serum albumin several weeks before recurrence in patients ≥ 15 years.