ABSTRACT
RATIONALE: Even though it is the most common primary glomerular disease, the natural history and prognosis of IgM associated nephrotic syndrome have not been well established. OBJECTIVES: To determine the (1) responsiveness to prednisolone therapy, (2) long-term clinical and laboratory outcomes, and (3) prognostic indicators to prednisolone therapy in patients with IgM associated nephrotic syndrome. STUDY DESIGN: Clinical descriptive, longitudinal study. SUBJECTS: Seventy two biopsy-proved IgM associated nephrotic syndrome patients, diagnosed between 1978-1996 at Vajira Hospital, Bangkok, were included in the study. METHOD: Clinical parameters with age, sex, duration of edema, blood pressure and laboratory findings such as hematuria, BUN, creatinine, albumin, and cholesterol, 24-hour urine protein, and stool examination, were collected pre-renal biopsy. Each patient was treated with 45-60 mg of prednisolone according to body weight, for up to 8 weeks. Each patient was followed-up every 4-weeks for clinical and laboratory evaluations, and for adjusting the steroid dosage. Clinical responses were stratified into 3 groups as steroid responsive (SRP), steroid dependent (SD), and steroid resistant (SRS). MAIN OUTCOME MEASURES: (1) Frequency and types of steroid responsiveness. (2) Incidence of hypertension, hematuria, renal insufficiency, end-stage renal disease, and survival during the follow-up. (3) Prognostic indicators for initial clinical response to prednisolone, and for long-term morbidity and mortality. RESULTS: Forty eight of the 72 patients (66.67%) were responsive to prednisolone at 8-weeks, the 24 remaining patients (33.33%) were nonresponsive. High proteinuria of 7.66 +/- 4.14 g/D was the only good prognostic indicator to initial prednisolone therapy (p < 0.03). During the follow-up, 42(58.33%), 26(36.11%), and 4(5.56%) patients were SRP, SD, and SRS, respectively. There were no prognostic indicators associated with long-term steroid responsiveness. Of the 60 patients followed-up for more than one year; 34, 15 and 11 patients were followed-up for 1-5, > 5-10 and > 10 years, respectively. Hematuria and proteinuria were more frequent among the SRS group (p < 0.01 and 0.02, respectively) during the follow-up. Only one patient, initially in the SD group, and later on became SRS, died. CONCLUSION: Patients with IgM associated nephrotic syndrome had very good response to prednisolone therapy. It had a very slow progressive course, with low morbidity and mortality.