High cost and low survival rate in high comorbidity incident elderly hemodialysis patients

Abstract

Background: The comorbidity index is a predictor of mortality in dialysis patients but there are few reports for predicting elderly dialysis mortality and national population-based cost studies on elderly dialysis. The aim of this study was to evaluate the long-term mortality of incident elderly dialysis patients using the Deyo-Charlson comorbidity index (CCI) and to assess the inpatient and outpatient visits along with non-dialysis costs.

Methods: Data were obtained from catastrophic illness registration of the Taiwan National Health Insurance Research Database. Incident elderly dialysis patients (age ≥75 years) receiving hemodialysis for more than 90 days between Jan 1, 1998, and Dec 31, 2007, were included. Baseline comorbidities were determined one year prior to the first dialysis day according to ICD-9 CM codes. Survival time, mortality rate, hospitalization time, outpatient visit frequency, and costs were calculated for different age and CCI groups.

Results: In 10,759 incident elderly hemodialysis patients, hazard ratios for all-cause mortality were significantly increased in the different age groups (p < 0.001) and CCI patients (p < 0.001). Death rates increased with both increasing age and CCI score. High comorbidity incident hemodialysis and elderly patients were found to have increased length of hospital stay and total hospitalization costs.

Conclusions: This population-based cohort study indicated that both age and higher CCI values were predictors of survival in incident elderly hemodialysis. Increased costs and mortality rates were evident in the oldest patients and in those with high CCI scores. Conservative treatment might be considered in high comorbidity and low-survival rate end stage renal disease (ESRD) patients.

Figure 1. Survival curve stratified by age and Charlson comorbidity index (CCI) (A) Kaplan-Meier curves for 10 year survival by age.

(B) Kaplan-Meier curves for 10 year survival by CCI. Survival calculations start 90 days after beginning dialysis. The survival rate of incident elderly hemodialysis patients declined as age and CCI increased.

Figure 2. Increase mortality with increased age and CCI in incident elderly hemodialysis cohort.

The bars represent hazard ratios by age group and CCI.

Figure 3. Hospitalization days per year and total hospitalization cost stratified by age and Charlson comorbidity index in elderly hemodialysis patients.

(A) Increased duration of hospital stay for patients in the same age group with increased CCI levels (B) Increased mean admission costs (US dollars) for patients in the same age group with increased CCI levels (one United States dollars = 32.59 New Taiwan dollars).