Predictors of mortality among hemodialysis patients in Hamadan Province using random survival forests


Hemodialysis; Kidney Failure; Survival; Random Survival Forest


Background: Hemodialysis patients are at the high risk for morbidity and mortality. The aim of this study was to find out the predictors of mortality and survival in hemodialysis patients in Hamadan province.

Methods: The numbers of 785 patients during the entire 11 years were enrolled into this historical cohort study. Data were gathered by a checklist of hospital records. The survival time was the time between start of Hemodialysis treatment to patients death as the end point. Random survival forests (RSF) method was used to identify main predictors of survival among the patients.

Results: The median survival time was 613 days. The number of 376 death was occurred. The three most important predictors of survival were hemoglobin, CRP and albumin. RSF method predicted survival better than the conventional Cox-proportional hazards model (out-of-bag C-index of 0.808 for RSF vs. 0.727 for Cox model).

Conclusions: We found that higher levels of CRP, low serum albumin and low serum hemoglobin were the top three most important predictors of survival for HD patients.


1. Grassmann A, Gioberge S, Moeller S, Brown G. ESRD patients in 2004: global overview of patient numbers, treatment modalities and associated trends. Nephrology Dialysis Transplantation. 2005;20(12):2587-93.
2. Collins AJ, Foley RN, Herzog C, Chavers B, Gilbertson D, Ishani A, et al. US renal data system 2010 annual data report. American Journal of Kidney Diseases. 2011;1(57):A8, e1–526.
3. Mafra D, Farage NE, Azevedo DL, Viana GG, Mattos JP, Velarde LGC, et al. Impact of serum albumin and body-mass index on survival in hemodialysis patients. International urology and nephrology. 2007;39(2):619-24.
4. Mousavi SSB, Hayati F, Ansari MJA, Valavi E, Cheraghian B, Shahbazian H, et al. Survival at 1, 3, and 5 years in diabetic and nondiabetic patients on hemodialysis. Iranian journal of kidney diseases. 2010;4(1):74.
5. Montaseri M, Yazdani Cherat J, Espahbodi F, Mousavi SJ. Five-year survival rate in hemodialysis patients Attending Sari Imam Khomeini Hospital. Journal of Mazandaran University of Medical Sciences. 2013;23(101):78-85.
6. Bleyer AJ, Tell GS, Evans GW, Ettinger WH, Burkart JM. Survival of patients undergoing renal replacement therapy in one center with special emphasis on racial differences. American journal of kidney diseases. 1996;28(1):72-81.
7. Brodowska-Kania D, Rymarz A, Gibin K. First year survival of patients on maintenance dialysis treatment in Poland. Nagoya journal of medical science. 2015;77(4):629.
8. Akizawa T, Saito A, Gejyo F, Suzuki M, Nishizawa Y, Tomino Y, et al. Low Hemoglobin Levels and Hypo-Responsiveness to Erythropoiesis-Stimulating Agent Associated With Poor Survival in Incident Japanese Hemodialysis Patients. Therapeutic Apheresis and Dialysis. 2014;18(5):404-13.
9. Iseki K, Tozawa M, Takishita S. Effect of the duration of dialysis on survival in a cohort of chronic haemodialysis patients. Nephrology Dialysis Transplantation. 2003;18(4):782-7.
10. Slinin Y, Greer N, Ishani A, MacDonald R, Olson C, Rutks I, et al. Timing of dialysis initiation, duration and frequency of hemodialysis sessions, and membrane flux: a systematic review for a KDOQI clinical practice guideline. American Journal of Kidney Diseases. 2015;66(5):823-36.
11. VanderWeele TJ, Knol MJ. A tutorial on interaction. Epidemiologic Methods. 2014;3(1):33-72.
12. de González AB, Cox DR. Interpretation of interaction: A review. The Annals of Applied Statistics. 2007;1(2):371-85.
13. de Mutsert R, Grootendorst DC, Axelsson J, Boeschoten EW, Krediet RT, Dekker FW, et al. Excess mortality due to interaction between protein-energy wasting, inflammation and cardiovascular disease in chronic dialysis patients. Nephrology Dialysis Transplantation. 2008;23(9):2957-64.
14. Zitt E, Lamina C, Sturm G, Knoll F, Lins F, Freistätter O, et al. Interaction of time-varying albumin and phosphorus on mortality in incident dialysis patients. Clinical Journal of the American Society of Nephrology. 2011;6(11):2650-6.
15. Hallan S, de Mutsert R, Carlsen S, Dekker FW, Aasarød K, Holmen J. Obesity, smoking, and physical inactivity as risk factors for CKD: are men more vulnerable? American journal of kidney diseases. 2006;47(3):396-405.
16. Harrell FE, Jr., Califf RM, Pryor DB, Lee KL, Rosati RA. Evaluating the yield of medical tests. Jama. 1982;247(18):2543-6.
17. Regidor DL, Kopple JD, Kovesdy CP, Kilpatrick RD, McAllister CJ, Aronovitz J, et al. Associations between changes in hemoglobin and administered erythropoiesis-stimulating agent and survival in hemodialysis patients. Journal of the American Society of Nephrology. 2006;17(4):1181-91.
18. Gilbertson DT, Ebben JP, Foley RN, Weinhandl ED, Bradbury BD, Collins AJ. Hemoglobin level variability: associations with mortality. Clinical Journal of the American Society of Nephrology. 2008;3(1):133-8.
19. Berweck S, Hennig L, Sternberg C, Dingerkus H, Ludat K, Hampl H. Cardiac mortality prevention in uremic patients. Therapeutic strategies with particular attention to complete correction of renal anemia. Clinical nephrology. 2000;53(1 Suppl):S80-5.
20. Kausz AT, Khan SS, ABICHANDANI R, Kazmi WH, Obrador GT, Ruthazer R, et al. Management of patients with chronic renal insufficiency in the Northeastern United States. Journal of the American Society of Nephrology. 2001;12(7):1501-7.
21. Ofsthun N, Labrecque J, Lacson E, Keen M, Lazarus JM. The effects of higher hemoglobin levels on mortality and hospitalization in hemodialysis patients. Kidney international. 2003;63(5):1908-14.
22. Kalantar-Zadeh K, Supasyndh O, Lehn RS, McAllister CJ, Kopple JD. Normalized protein nitrogen appearance is correlated with hospitalization and mortality in hemodialysis patients with Kt/V greater than 1.20. Journal of renal nutrition. 2003;13(1):15-25.
23. Kalantar-Zadeh K, Kilpatrick RD, Kuwae N, McAllister CJ, Alcorn Jr H, Kopple JD, et al. Revisiting mortality predictability of serum albumin in the dialysis population: time dependency, longitudinal changes and population-attributable fraction. Nephrology Dialysis Transplantation. 2005;20(9):1880-8.
24. Mafra D, Farage NE, Azevedo DL, Viana GG, Mattos JP, Velarde LG, Fouque D. Impact of serum albumin and body-mass index on survival in hemodialysis patients. International urology and nephrology. 2007;39(2):619-24.
25. Combe C, Chauveau P, Laville M, Fouque D, Azar R, Cano N, et al. Influence of nutritional factors and hemodialysis adequacy on the survival of 1,610 French patients. American journal of kidney diseases. 2001;37(1):S81-S8.
26. Yeun JY, Levine RA, Mantadilok V, Kaysen GA. C-reactive protein predicts all-cause and cardiovascular mortality in hemodialysis patients. American Journal of Kidney Diseases. 2000;35(3):469-76.
27. Wasserman S, Rosanio S, Tiblier E, Sperger H, Tocchi M, Christenson R, et al. Cardiac troponin T and C-reactive protein for predicting prognosis, coronary atherosclerosis, and cardiomyopathy in patients undergoing long-term hemodialysis. Jama. 2003;290(3):353-9.
28. Iseki K, Tozawa M, Yoshi S, Fukiyama K. Serum C-reactive protein (CRP) and risk of death in chronic dialysis patients. Nephrology Dialysis Transplantation. 1999;14(8):1956-60.
29. Furuland H, Linde T, Ahlmén J, Christensson A, Strömbom U, Danielson BG. A randomized controlled trial of haemoglobin normalization with epoetin alfa in pre‐dialysis and dialysis patients. Nephrology Dialysis Transplantation. 2003;18(2):353-61.