Boudville N et al. (2006) Meta-analysis: risk for hypertension in living kidney donors. Ann Intern Med 145: 185–196

A recently reported meta-analysis investigated whether normotensive adults who donate a kidney are at greater risk of hypertension than healthy non-donors.

The authors used MEDLINE, EMBASE and the Science Citation Index to identify studies published from 1966 to 2005 that included at least 10 healthy normotensive adults who had donated a kidney and had had their blood pressure measured at least 1 year afterwards. They selected 48 studies that followed a total of 5,145 kidney donors for an average of 7 years after donation (range 1–25 years). Pooled results from 10 studies that included data on non-donor control participants showed that, approximately 10 years after transplant surgery, blood pressure was about 5 mmHg higher (6 mmHg systolic, 4 mmHg diastolic) in donors than in control participants. One of six controlled studies assessing risk of hypertension after kidney donation found the risk to be increased in donors compared with control participants (relative risk 1.9); there was statistical heterogeneity between the six studies, however, so results were not pooled. Among the donor cohorts, predonation features associated with larger increases in blood pressure, higher blood pressure, or hypertension after donation included older age, male sex, higher blood pressure, greater than ideal body weight, and lower glomerular filtration rate.

The authors conclude that within 5–10 years of donation, living kidney donors might have a 5 mmHg higher increase in blood pressure than would occur as a result of normal aging. Prospective, controlled studies to better estimate long-term risks are needed, to improve donor selection, informed consent, and best practices that maintain the wellbeing of previous and future donors.