Comparing Dialysis Modality and Cardiovascular Mortality in Patients on Hemodialysis and Peritoneal Dialysis

Abstract

Patients undergoing dialysis are at high risk for cardiovascular disease (CVD). Mortality differences between peritoneal dialysis (PD) and hemodialysis (HD) are widely debated. The question of whether dialysis modality affects the risk for CVD remains to be addressed.In the present study, we evaluated the influence of hemodialysis (HD) and peritoneal dialysis (PD) on survival and the risk of developing de novo CVD. Our observational prospective study enrolled 157 end-stage renal disease patients on HD or PD for 12 months. Patients with a history of malignancy, chronic rheumatic heart disease, congenital heart disease, previous cardiac surgery, or previous transplantation, and patients started on dialysis less than 3 months earlier were excluded from the study. Detailed medical history, demographic data, and routine laboratory investigations were obtained, and patients were follow every 3 months for 12 months. Cardiac echography was performed at baseline and at 6 months. Nutrition status was scored using the standardized 7-point subjective global assessment (SGA). Baseline comorbidities included the presence or absence of coronary artery disease (angina, myocardial infarction, and coronary artery bypass surgery), peripheral vascular disease, hypertension, diabetes mellitus, and cerebrovascular disease.Of the 157 patients, 121 were on HD (60 men, 61 women; mean age: 59.3 years), and 36 were on PD (14 men, 22 women; mean age: 50.8 years, p = 0.13). The dialysis duration was significantly different in the two groups (HD: 52.96 ± 38.3; PD: 30.89 ± 26.3; p = 0.02). Of the HD patients, 95.04% were hypertensive, and 61.98% were diabetic; of the PD patients, 91.66% were hypertensive, and 50% were diabetic. Body mass index and SGA score were not significantly different between the two groups. Patients on PD had a higher residual urine volume (383.66 ± 548.393 mL vs. 12.40 ± 96.238 mL in the HD patients, p < 0.001).In comparing traditional cardiovascular risk factors at the start of the study, PD patients had higher levels of total cholesterol (4.5 ± 1.33 mmol/L vs. 3.85 ± 1.34 mmol/L in HD patients, p < 0.05), low-density lipoprotein cholesterol (2.84 ± 1.31 mmol/L vs. 2.06 ± 0.89 mmol/L, p < 0.001), high-density lipoprotein cholesterol (1.10 ± 0.26 mmol/L vs. 0.91 ± 0.32 mmol/L, p < 0.005). Cardiovascular morbidity affected 17 HD patients and 2 PD patients. A Cox proportional hazards model for cardiovascular events showed a trend suggesting that PD was safer, but the data did not reach statistical significance. Kaplan-Meir survival analysis revealed 12 death events in HD patients compared with 4 events in PD patients-a difference that was not statistically significant.Cardiovascular morbidity during chronic dialysis was prevalent among the older patients (>57 years) and those who used more than 1 antihypertensive medication; an ejection fraction exceeding 53% was found to be cardioprotective. For all-cause mortality, dialysis modality was a nonsignificant risk factor; age and Kt/V were significant.