Clinical features of renal amyloidosis: An analysis of 40 patients in a 28-year follow-up

Abstract

Objective Although rare, renal amyloidosis is an important diagnosis that bares a significant morbidity and mortality. The purpose of this study was to present current single center experience in the past 28 years. Methods A total of 6151 kidney biopsies were performed in our hospital from Jan. 1983 to Dec. 2010; 5844 were native kidney biopsies. Cases with a diagnosis of renal amyloidosis were identified through a search of our data bank and the clinical data were retrieved from medical charts. The patients were further classified as AL type and non-AL type. The trend of incidence was analyzed and the clinical features were compared. Risk factors that predict patient mortality were discovered by logistic regression analysis. Results Forty out of 5844 native kidney biopsies (0.68%) were identified as renal amyloidosis. Eighteen (45%) were of AL type. The mean age at diagnosis was 62.6 ± 13.4 years. Male was the predominant gender that was involved. Clinically, most (80%) have nephrotic range proteinuria (mean 24 hours urine protein: 6.9 ± 4.7 g). With a mean follow-up duration of 1155 day, the 1-year and 5-year patient survival were 42.9% and 17.9%, respectively. eGFR at biopsy was the sole predictive factor for patient survival. Conclusion Senile patients with nephrotic syndrome should elicit the suspicion of renal amyloidosis. The incidence appeared to be increasing and the prognosis poor. © 2011 The Japanese Society of Internal Medicine.