Hypertension, cardiovascular disease and cause of death in Danish living kidney donors: matched cohort study

OBJECTIVES: We aimed to investigate the long-term absolute risk of hypertension and cardiovascular disease after kidney donation in living kidney donors. DESIGN: Living kidney donors were matched to 10 controls from the general population. SETTING: Multiple Danish national registries were used to identify living kidney donors from 1 January 1996 to 31 December 2017 nationwide. PARTICIPANTS: 1262 living kidney donors and 12 620 controls. MAIN OUTCOME MEASURES: Hypertension, cardiovascular disease and diabetes. RESULTS: The median age of living kidney donors was 52 (men 43%). Hypertension developed in 50 (4%) and 231 (1.8%) with a median follow-up of 7 years (IQR 3.3–12.1 years with a maximum follow-up of 22 years) and 6.9 years (IQR 3.2–11.7 years and maximum follow-up of 22 years) for donors and controls, respectively. The absolute risk of hypertension was 2.3% (95% CI 1.4% to 3.2%) and 1.2% (95% CI 1.0% to 1.4%), 4.2% (95% CI 2.8% to 5.7%) and 2.4% (95% CI 2.1% to 2.8%), 8.6% (95% CI 6.0% to 11.3%) and 3.3% (95% CI 2.8% to 3.8%) within 5, 10, 15 years for donors and controls, respectively. The ratio of the 10-year absolute risks for hypertension was 1.64 (95% CI 1.44 to 1.88) for donors compared with the controls. Two donors and four controls developed renal replacement therapy requiring end-stage renal disease during follow-up. The absolute risk of cardiovascular disease and diabetes was 7.3% (95% CI 5.7% to 9.5%) and 8.3% (95% CI 7.7% to 9.0%), 1.7% (95% CI 0.7% to 2.8%) and 3.2% (95% CI 2.7% to 3.6%) at 10 years for donors and controls, respectively. CONCLUSIONS: Living kidney donors have an increased long-term absolute risk of hypertension compared with controls from the general population.