Prevalence and Causes of Proteinuria in Kidney Transplant Recipients: Data from a Single Center

Abstract

Introduction. Proteinuria after renal transplantation increases the risk of graft failure and mortality. The aim of the study was to determine the prevalence and causes of proteinuria in kidney transplant recipients. Methods. All kidney transplant recipients followed up in our clinic were included in the study. As a center protocol 24-hour urine collections were used to quantify protein excretion with 3-month intervals posttransplantation during the first year, and yearly thereafter. The etiology of chronic kidney disease and demographic characteristics of the study group were obtained from outpatient records. Data regarding the immunosuppressive regimens used, 24-hour proteinuria levels and creatinine clearences, new-onset hypertension, new-onset diabetes mellitus, rejection episodes, infections like cytomegalovirus (CMV) and polyoma (BK), and biopsy findings were noted. Results. A total of 260 kidney transplant recipients (97 females, mean age 42.3±12.3 years) were evaluated. Median follow-up period was 36 months; 137 of all transplantations were from living donors. Mean age of donors was 42.7±15 years and 133 were female. Proteinuria with protein excretion ≥300 mg/d was present in 35.4% of patients. The most common cause of biopsy-proven proteinuria was transplant-specific conditions (acute rejection, and borderline changes). Conclusion. The prevalence of proteinuria was 35.4%. The transplant-specific diagnoses were the most likely causes. Even in nonnephrotic ranges it was associated with decreased graft survival.

Time-Varying Proteinuria and the Risk of Cardiovascular Disease and Graft Failure in Kidney Transplant Recipients

“…5,8,9 Proteinuria is frequently observed after kidney transplantation and is prevalent among 11 to 45% of recipients with a functioning graft. 1,10,11 Proteinuria is a known indicator of glomerular damage and is reported to be an independent risk factor of further disease progression. It is believed that excess proteins filtered by the glomerulus causes an interstitial inflammatory response that leads to lesions and scarring of the tubular interstitium.…”

“…13–16 It also results in a greater risk of poor graft outcomes and mortality in kidney transplant recipients. 1,15–20 Specifically, recipients with a urine protein/creatinine ratio greater than 1.0 during the third month posttransplant were approximately twice as likely to have a cardiovascular event, sixteen times more likely to have graft failure, and three times more likely to die with a functioning graft compared to those without significant proteinuria. 3,21…”

“…Cardiovascular disease (CVD) is a major cause of morbidity and death among kidney transplant recipients and contributes significantly to poor graft outcomes. 1–4 The rates of cardiovascular events and cardiovascular mortality in kidney transplant recipients are 50 times and 10 times higher than in the general population, respectively. 5 Moreover, approximately half of recipients die with a functioning graft 6 and about 30% of these deaths are attributable to CVD.…”