P-637: The role of hypertension before admission on dialysis and survival during hemodialysis

Hypertension is common in patients with chronic renal failure (CRF), however the role of hypertension as a predictor of mortality in dialysis patients is controversial. The influence of hypertension before admission on dialysis and the mortality during hemodialysis was studied. Other potential risk factors such age, sex, renal disease, comorbidity, past history of atherosclerosis (heart, cerebral or peripheral arteries ischemic disease), electrocardiographyc left ventricular hypertrophy (LVH), X-ray vascular calcifications (VC) and serum albumin concentration were also taken into account. Patients and Methods. Two hundred and one patients, 124 (62%) males and 77 (38%) females(mean age: 51 years) were followed up for 78 months after starting dialysis. The patients were classified according to the blood pressure measurements obtained during the follow-up period of the renal disease, considering three groups: normotensive (NH), controlled hypertensive (c-HT) (blood pressure < 140/90), and uncontrolled hypertensive (uc-HT) (blood pressure >140/90). Kaplan-Meier analysis and Cox's Proportional Hazards Model were used for statistical analysis. Results. From the 201 patients, 184 were enrolled. The mean age was similar in all groups. The prevalence of NH, c-HT and un-HT was 27% (n= 49), 36% (n=66), and 37% (n=66) respectively. The prevalence of atherosclerosis was higher in the hypertensive group (NH 14% (n=6) vs c-HT 49% (n= 21) vs un-HT 37% (n= 16), p=0.046). Left ventricular hypertrophy was also higher in hypertensive patients (NH 13% (n=10) vs c-HT 48% (n= 37) vs un-HT 39% (n= 30), p=0.0005), as well as vascular calcifications (NH 18%(n=13) vs c-HT 39%(n= 28) vs un-HT 43% (n= 31), p=0.103). Survival rates at 1, 3, 5, and 10 years of the un-HT group were significantly worse (Log-Rank test, p=0.0066). Comorbidity (RR: 2.25 (1.43-3.54), p=0.0005) and uncontrolled hypertension (RR: 2.12 (1.22-3.70), p=0.0074) were independent predictors of mortality. In addition, the percentage of uncontrolled hypertensive patients during hemodialysis was significantly higher in the uncontrolled hypertensive group in predialysis regarding the controlled hypertensive and normotensive group in predialysis (30% (n= 21) vs 9% (n= 6) vs 4% (n= 2)). Conclusion. Predialysis uncontrolled hypertension and comorbidity are independent predictors of mortality in hemodialysis patients. Uncontrolled hypertensive patients during predialysis are worse controlled during hemodialysis. In addition, these results suggest association between history of atherosclerosis and left ventricular hypertrophy with hypertension.