Identification of effective factors on survival of hemodialysis patients via LASSO-Cox approach

Hemodialysis is a method for removing excess fluid and uremic waste from the body of chronic renal-failure patients. In patients with (CRF), hemodialysis stops death. Various factors can affect the survival of patients undergoing hemodialysis treatment. The current study aimed to determine such factors.

The aim of study was to determine some factors affecting the hemodialysis patients' survival using the LASSO-Cox approach.

This cross-sectional study examined 252 patients undergoing hemodialysis from 2010 to 2016 in all of hospitals in Bandar Abbas- Iran, whose data had been recorded in the hemodialysis unit or it was possible to get their files. The Cox model under the LASSO variable selection technique (LASSO-Cox) was applied for data analysis. The collected data was analyzed using SPSS 23.0 (IBM) software and through glmnet and survival packages in software R version 3.5.1.

In this study, 35 (13.9%) death events was observed. The mean follow up time of 252 patients was equal to 10.93 ± 7.82 years. Based on the results of the Cox-Lasso, The risk of mortality for patients with diploma degree was by 49% lower than that of the illiterate group (HR = 0.51; 95%CI:(0.02,0.57); P=0.021). The risk of death for unemployed patients and farmers was equal to 0.66 (HR = 1.66; 95%CI:(1.51,25.79); P=0.004) and 0.29 (HR = 1.29; 95%CI:(1.14,27.40); P=0.005), respectively, higher than that of employees. Also, an increase in the frequency of dialysis per week, the risk of death reduced by 0.34(HR = 0.66; 95%CI:(0.04,0.82); P=0.022), and one unit increase in the duration of dialysis per hour increased the risk of death by 2.23 times (HR = 2.23; 95%CI:(1.41,27.1); P=0.010).

Education level, job, frequency of hemodialysis per week, and duration of hemodialysis per hour were the most important variables in survival of hemodialysis patients. As a result, it seems that more education to nurses working in hemodialysis wards and patients involved can be useful to heed to recommendations of physicians in terms of the required duration for hemodialysis per hour and the number of sessions per week.