[Shortening of life expectancy in patients with membranous nephropathy--based on 20 years follow up study]

It is not certain whether the life expectancy of patients with membranous nephropathy is shorter than that of an age-matched healthy population. Forty-one patients (21 males, 20 females) aged between 16 and 70 years (average age: 33.3 years) were followed for 20 years. The patients were divided into two groups: group I (n = 18), consisting of patients in whom nephrotic syndrome persisted for more than two years or until death, and group II (n = 23), consisting of patients except for group I. The non-survival criteria are death or renal death. Twelve patients (29.3%) died during the study period. Eight patients belonged to group I and 4 to group II. The causes of death in group I patients were end-stage renal failure in 3 cases, ischemic heart disease in 1 case, subarachnoid hemorrhage in 1 case, malignancy in 2 cases, suicide in 1 case, and those in the group II patients were pneumonia, malignancy, cerebral softening, and diabetes mellitus, respectively. Eight patients who died in group I had a significantly longer difference between their actual life span (ALS) and life expectancy (LE) and a significantly smaller ratio of ALS to LE than the patients who died in group II (ALS-LE: -29.9 +/- 4.5 years in group I vs. -9.0 +/- 6.8 years in group II, p < 0.05, ALS x 100/LE: 22.5 +/- 8.0% in group I vs. 80.9 +/- 25.2% in group II, p < 0.05). In group I, the ratio of observed to expected death was 4.76 (95% confidence interval, 2.05 to 9.37) and significantly higher than that of the control population. In group II, however, the ratio was 1.09 (95% confidence interval, 0.30 to 2.80), and the difference from the control population was not statistically significant. These results suggest that longstanding nephrotic syndrome is associated with a shortened life expectancy in patients with membranous nephropathy.