PROGNOSIS OF UNTREATED PATIENTS WITH IDIOPATHIC MEMBRANOUS NEPHROPATHY

Background. Defining the most appropriate treatment for patients with idiopathic membranous nephropathy is a matter of controversy. The cour se of the disorder is often benign, and the immunosuppressive regimens used in some patients have uncertain benefits and substantial risks. We studied the natural history of idiopathic membranous nephropathy in patients who received only symptomatic therapy. Methods. We prospecti vely studied 100 consecutive patients (68 men and 32 women; mean [+/-S D] age, 51+/-17 years) with biopsy-proved idiopathic membranous nephro pathy. The patients received diuretic or antihypertensive drugs as nee ded, but no glucocorticoid or immunosuppressive drugs. We examined the patients and measured their urinary protein excretion and serum creat inine concentrations every 6 months for a mean of 52 months. Results. Twenty-four (65 percent) of the 37 patients followed for at least five years had complete or partial remission of proteinuria; in 6 others ( 16 percent), end-stage renal disease developed, and they required dial ysis. As calculated by the Kaplan-Meier method, the estimated probabil ity (+/- the standard error of the estimate) of retaining adequate kid ney function was 88+/-5 percent after five years and 73+/-7 percent af ter eight years. The prognosis was poorer in men and in patients over 50 years of age, but not in patients with the nephrotic syndrome, hype rtension, or hypercholesterolemia. Conclusions. Most untreated patient s with idiopathic membranous nephropathy maintain renal function for p rolonged periods and are likely to have spontaneous remission. These r esults do not support the use of glucocorticoids and immunosuppressive drugs in patients with idiopathic membranous nephropathy.