A prospective controlled study of living kidney donors: three-year follow-up.

BACKGROUND: There have been few prospective controlled studies of kidney donors. Understanding the pathophysiologic effects of kidney donation is important for judging donor safety and improving our understanding of the consequences of reduced kidney function in chronic kidney disease. STUDY DESIGN: Prospective, controlled, observational cohort study. SETTING & PARTICIPANTS: 3-year follow-up of kidney donors and paired controls suitable for donation at their donor's center. PREDICTOR: Kidney donation. OUTCOMES: Medical history, vital signs, glomerular filtration rate, and other measurements at 6, 12, 24, and 36 months after donation. RESULTS: At 36 months, 182 of 203 (89.7%) original donors and 173 of 201 (86.1%) original controls continue to participate in follow-up visits. The linear slope of the glomerular filtration rate measured by plasma iohexol clearance declined 0.36±7.55mL/min per year in 194 controls, but increased 1.47±5.02mL/min per year in 198 donors (P=0.005) between 6 and 36 months. Blood pressure was not different between donors and controls at any visit, and at 36 months, all 24-hour ambulatory blood pressure parameters were similar in 126 controls and 135 donors (mean systolic blood pressure, 120.0±11.2 [SD] vs 120.7±9.7mmHg [P=0.6]; mean diastolic blood pressure, 73.4±7.0 vs 74.5±6.5mmHg [P=0.2]). Mean arterial pressure nocturnal dipping was manifest in 11.2% ± 6.6% of controls and 11.3% ± 6.1% of donors (P=0.9). Urinary protein-creatinine and albumin-creatinine ratios were not increased in donors compared with controls. From 6 to 36 months postdonation, serum parathyroid hormone, uric acid, homocysteine, and potassium levels were higher, whereas hemoglobin levels were lower, in donors compared with controls. LIMITATIONS: Possible bias resulting from an inability to select controls screened to be as healthy as donors, short follow-up duration, and dropouts. CONCLUSIONS: Kidney donors manifest several of the findings of mild chronic kidney disease. However, at 36 months after donation, kidney function continues to improve in donors, whereas controls have expected age-related declines in function.

Association of preventive health care with atherosclerotic heart disease and mortality in CKD.

Chronic kidney disease (CKD, stages 1 to 4) affects approximately 13.1% of United States adults and leads to ESRD, cardiovascular disease, and premature death. Here, we assessed adherence to a subset of Kidney Disease Outcomes Quality Initiative preventive health care guidelines and identified associations between adherence and incident atherosclerotic heart disease (ASHD). Using the Medicare 5% data set, 1999 to 2005 (about 1.2 million patients per year), we created 3-yr rolling cohorts. We classified CKD and diabetes during year 1, assessed preventive care during year 2, and evaluated ASHD outcomes during year 3. We defined preventive care by the receipt of laboratory measurements (serum creatinine, lipids, calcium and phosphorus, parathyroid hormone, and, for patients with diabetes, hemoglobin A1c), influenza vaccination, and by at least one outpatient visit to a nephrologist. Among patients with CKD, 80% received >or=2 serum creatinine tests during the year, and only 11% received parathyroid hormone testing. Cumulative incidence of the combined ASHD outcome was 25% and 11% for patients with and without prevalent cardiovascular disease, respectively. Except for serum creatinine testing, preventive care associated with lower ASHD rates in the subsequent year, ranging from 10% lower for those who received influenza vaccinations and >or=2 A1c tests, to 43% lower for calcium-phosphorus assessment. Receiving >or=2 serum creatinine tests associated with a 13% higher rate of ASHD. A higher number of preventive measures associated with lower rates of ASHD. In summary, these data support an association between preventive measures and reduced cardiovascular morbidity and mortality.