Survival Percentile and Predictors of Difference in Survival among HemodialysisPatients and Their Additive Interaction Using Laplace Regression

Background: identifying survival modifiable factors and additive interaction between them couldhelp in prioritizing the clinical care of hemodialysis (hd) patients. we aimed to examine the survivalrate and its predictors in hd patients; and explore the additive interaction between survivalmodifiable factors.study design: a retrospective cohort study.methods: the present study was performed on 1142 hd patients in hamadan province, westerniran from 2007 to 2017. data were collected through a researcher-made checklist on hospitalrecords. laplace regression was used to evaluate differences in 40th survival percentiles in different levels of predictors as well as exploring the pairwise additive interactions between variables.results: we observed significantly higher survival in nonsmoker patients (40th percentile difference= 5.34 months, 95% ci: 2.06, 8.61). survival was shorter by more than 3 years in crp positivepatients (40th percentile difference=36.9 months, 95% ci: 32.37, 41.42). patients with normalalbumin (40th percentile difference =24.92, 95% ci: 18.04, 31.80) and hemoglobin (40th percentiledifference = 18.65, 95% ci: 12.43, 24.86) had significantly higher survival (p<0.001). there wassuperadditive interaction between being crp negative and nonsmoker (β3 = 9.42 months, 95% ci:3.35, 15.49 (p=0.002)).conclusion: high crp and low serum albumin and hemoglobin were associated with theincreased risk of death in hd patients. the results of this study support the presence of superadditiveinteraction between crp status with serum hemoglobin and also crp status with smoking,resulting in excess survival in hd patients.