Dialysis outcomes in Colombia (DOC) study: A comparison of patient survival on peritoneal dialysis vs hemodialysis in Colombia

• DOI: 10.1038/sj.ki.5002619
• Publication Date: 2008-03-31T13:54:36Z
• Authors: M. Sanabria; J. Muñoz; C. Trillos; G. Hernández; C. Latorre; C.S. Díaz; S. Murad; K. Rodríguez; Á Rivera; A. Amador; F. Ardila; A. Caicedo; D. Camargo; A. Díaz; J. González; H. Leguizamón; P. Lopera; L. Marín; I. Nieto; E. Vargas
• Keywords: Male; Survival; Chronic kidney failure; Comorbidity; Phosphate blood level; Kaplan-Meier Estimate; Diabetes mellitus; Continuous ambulatory peritoneal dialysis; 0302 clinical medicine; Diabetes complications; Peritoneal Dialysis, Continuous Ambulatory; Treatment outcome; Middle aged; Priority journal; Outcome; Aged, 80 and over; 2. Zero hunger; Phosphorus; Patient education; Middle Aged; Cardiovascular disease; Kaplan-meiers estimate; Multicenter study; 3. Good health; Clinical trial; chronic; Blood; Treatment Outcome; Hemodialysis; Female; Peritoneal Dialysis; Age distribution; Human; Adult; Proportional hazards models; Adolescent; Peritoneal dialysis; Kidney failure; Major clinical study; Follow-up studies; Proportional hazards model; Socioeconomic factors; Colombia; Article; Hemodialysis patient; Diabetes Complications; 03 medical and health sciences; Kidney function; Humans; Mortality; Disease severity; Aged; Proportional Hazards Models; Small for date infant; Intermethod comparison; Methodology; continuous ambulatory; Follow up; Socioeconomic Factors; Socioeconomics; Kaplan meier method; Kidney Failure, Chronic; Comparative study; Controlled study; Dialysis; Follow-Up Studies

The goal of the Dialysis Outcomes in Colombia (DOC) study was to compare the survival of patients on hemodialysis (HD) vs peritoneal dialysis (PD) in a network of renal units in Colombia. The DOC study examined a historical cohort of incident patients starting dialysis therapy between 1 January 2001 and 1 December 2003 and followed until 1 December 2005, measuring demographic, socioeconomic, and clinical variables. Only patients older than 18 years were included. As-treated and intention-to-treat statistical analyses were performed using the Kaplan-Meier method and Cox proportional hazard model. There were 1094 eligible patients in total and 923 were actually enrolled: 47.3% started HD therapy and 52.7% started PD therapy. Of the patients studied, 751 (81.3%) remained in their initial therapy until the end of the follow-up period, death, or censorship. Age, sex, weight, height, body mass index, creatinine, calcium, and Subjective Global Assessment (SGA) variables did not show statistically significant differences between the two treatment groups. Diabetes, socioeconomic level, educational level, phosphorus, Charlson Co-morbidity Index, and cardiovascular history did show a difference, and were less favorable for patients on PD. Residual renal function was greater for PD patients. Also, there were differences in the median survival time between groups: 27.2 months for PD vs 23.1 months for HD (P=0.001) by the intention-to-treat approach; and 24.5 months for PD vs 16.7 months for HD (P<0.001) by the as-treated approach. When performing univariate Cox analyses using the intention-to-treat approach, associations were with age > or =65 years (hazard ratio (HR)=2.21; confidence interval (CI) 95% (1.77-2.755); P<0.001); history of cardiovascular disease (HR=1.96; CI 95% (1.58-2.90); P<0.001); diabetes (HR=2.34; CI 95% (1.88-2.90); P<0.001); and SGA (mild or moderate-severe malnutrition) (HR=1.47; CI 95% (1.17-1.79); P=0.001); but no association was found with gender (HR=1.03, CI 95% 0.83-1.27; P=0.786). Similar results were found with the as-treated approach, with additional associations found with Charlson Index (0-2) (HR=0.29; Cl 95% (0.22-0.38); P<0.001); Charlson Index (3-4) (HR=0.61; Cl 95% (0.48-0.79); P<0.001); and SGA (mild-severe malnutrition) (HR=1.43; Cl 95% (1.15-1.77); P<0.001). Similarly, the multivariate Cox model was run with the variables that had shown association in previous analyses, and it was found that the variables explaining the survival of patients with end-stage renal disease in our study were age, SGA, Charlson Comorbidity Index 5 and above, diabetes, healthcare regimes I and II, and socioeconomic level 2. The results of Cox proportional risk model in both the as-treated and intention-to-treat analyses showed that there were no statistically significant differences in survival of PD and HD patients: intention-to-treat HD/PD (HR 1.127; CI 95%: 0.855-1.484) and as-treated HD/PD (HR 1.231; CI 95%: 0.976-1.553). In this historical cohort of incident patients, there was a trend, although not statistically significant, for a higher (12.7%) adjusted mortality risk associated with HD when compared to PD, even though the PD patients were poorer, were more likely to be diabetic, and had higher co-morbidity scores than the HD patients. The variables that most influenced survival were age, diabetes, comorbidity, healthcare regime, socioeconomic level, nutrition, and education.