Background-Patients with end-stage kidney disease (ESKD) have a reduced life expectancy mainly as the result of cardiovascular diseases. Relaxin has been implicated in the pathogenesis of cardiovascular diseases. We analyzed the impact of relaxin on death in patients with ESKD. Methods and Results-Patients (n ϭ245; 122 women, 123 men) on long-term hemodialysis were followed for 1140 days for death. Blood samples for analysis of relaxin, C-reactive protein, Troponin T, cholesterol, HDL, brain natriuretic peptide, and albumin were taken at study entry. Survival was compared by the Kaplan-Meier method and Cox regression analysis. One hundred seven patients died during the observation period; 66 died of cardiovascular diseases and 28 died of infectious diseases. Elevated serum relaxin concentrations (greater than median) predicted death in male but not in female patients with ESKD: All-cause death (men: relative risk, 2.63; 95% CI, njections of serum from pregnant rabbits induced relaxation of the interpubic ligament of guinea pigs. 1 The hormone responsible for this action was named relaxin. Corpus luteum, decidua, and placenta secrete this hormone during pregnancy. Relaxin has many important roles in pregnancy, including softening effects on connective tissue, reducing uterine contractility, and control of mammary gland growth and differentiation. 1 Recently, however, it was recognized that relaxin also plays a role in the cardiovascular system. Patients with chronic heart failure have increased myocardial relaxin gene expression and elevated plasma relaxin concentrations. 2 Relaxin stimulates cardiac ANP secretion 3 and increases coronary blood flow through a nitric oxide-mediated mechanism. 3 It was furthermore shown that relaxin is a vasodilator of small systemic resistance arteries. 4 Relaxin is also involved in the regulation of cardiac 5 and renal 6 collagen synthesis.We analyzed whether relaxin is a mortality risk factor in patients with end-stage kidney disease (ESKD). Patients with ESKD have a substantially reduced life expectancy. The mortality risk is about 50% higher in elderly patients with ESKD and even much more in younger patients with ESDK as compared with age-matched persons without renal disease. 7,8
MethodsThe 245 patients (122 women, 123 men) were recruited from two dialysis centers (KfH Dialysezentrum-Neukölln, Berlin, and KfH Dialysezentrum-Moabit, Berlin). The patients are dialyzed at least 3 times weekly in 4-to 6-hour sessions, sufficient to provide an urea kinetic on dialysis (KT/V) of at least 1.3. The included patients represent all patients being on stable hemodialysis in these centers without actual health problems. All patients were included in the study in March 2000 and followed for 1140 days. The following patients characteristics were documented: age, gender, body mass index, cause of ESKD, time on dialysis, diabetes, hypertension, and coronary heart disease (patients with a history of myocardial infarction, coronary heart disease confirmed by heart catheterization, or typical ...