The adequacy of hemodialysis in end stage renal disease at Kenyatta National Hospital

Abstract

Background: Inadequate dialysis dose is closely related to mortality and morbidity of maintenance haemodialysis patients. Knowledge of patient related risk factors for inadequate delivery of haemodialysis would be helpful in selecting patient subgroups for intensive control of dialysis adequacy. The usual way to determine the adequacy of haemodialysis is based on measures of intradialytic urea reduction; the fractional clearance of urea (KW) and Urea reduction ratio (URR). The minimum optimal dose, targeted for adequacy of haemodialysis is KW of ~1.8 for patient on twice-weekly haemodialysis session and KW of ~1.2 for thrice weekly dialysis patient. While the minimum optimal dose, targeted for URR is 65% for thrice weekly dialysis patients and 80% for twice weekly dialysis. Haemodialysis product (HDP) is also used to assess adequacy of dialysis. A product of less than 45 is considered inadequate dialysis. Functional status of life as measured by Karnosky performance scale (KPS) and Modified Subjective global assessment (SGA) has been theorized to reflect adequacy of dialysis. Since these methods are easy to assess, hence the need to demonstrate any possible correlation with calculated adequacy of haemodialysis. Compliance of haemodialysis prescription is the major barrier to the adequacy of haemodialysis in patients with End stage renal disease (ESRD) in some of haemodialysis centers. Objectives: The main objective of this study was to determine the level of adequacy of haemodialysis in patients with ESRD at Kenyatta National hospital (KNH) renal unit. Other objectives included possible correlation between functional status of life, (as measured by KPS), modified SGA with adequacy of haemodialysis. Methods: All patients who met the inclusion criteria were recruited into the study. The study site was the renal unit of the KNH. Data, including demographic characteristics, dialysis data, compliance data, modified SGA and KPS were obtained from each patient. Blood for predialysis and post dialysis BUN sample were collected according to recommended procedures for dialysis quantification, in a single haemodialysis session. Urea reduction, using Kt I V and URR, and HOP was calculated for each patient. Results: Sixty-six patients were recruited. The male to female ratio was 2:1. The mean age group was 47 ± 14 years old. 82% of the patients underwent twice weekly dialysis schedule, and 13.6% underwent once weekly dialysis.83% had been dialysed for less than one year. The mean KtN and URR were 1.75 ± 0.72 and 72.36 ± 11.8% respectively. When using KtN, 34.8% (n=23) of the patients were adequately dialysed, and when assessed by URR, 22.7% (n=15) were adequately dialysed.There was a strong statistically significant correlation between KtN and URR (p=<0.001,r=0.742).Females, younger (less than 45 years) and underweight patients were more likely to have inadequate dialysis using URR and/or KtN (P value < o. 05). Conversely, patients dialysed once weekly (89%) and those with fistula (89%, n=17) were inadequately dialysed. All patients were inadequately dialysed when assessed by HDP method (HDP less than 45). There was no statistical correlation between adequacy of dialysis and KPS and SGA. Thirty-four percent of the patients were non-compliant to haemodialysis therapy, and the main reason was financial constraint in 91.3% of them. Conclusion: The level of adequacy of haemodialysis in our patients at KNH renal unit, is still very low compared to other haemodialysis centres. Functional status of life had no correlation with adequacy of dialysis and the utility of modified SGA, cannot be used as surrogate marker of adequacy of haemodialysis.