To determine if a patient receiving hemodialysis newly diagnosed with a malignancy might benefit from aggressive cancer treatment, an oncologist colleague posed the following question to me: “What is the typical survival rate for end-stage kidney disease (ESKD) patients on dialysis?”
In general, survival rates for patients on dialysis are poor. Based on the United States Renal Data System (USRDS) report, the adjusted survival rate for patients on hemodialysis (HD) is 57% at 3 years after onset of ESKD as compared to 68% for patients receiving peritoneal dialysis (PD). The 5-year survival for patients receiving HD and PD is 42% and 52%, respectively. With deceased donor kidney transplantation, 3-year survival improves to 85%. For comparison, the general population survival rate (matched for age and sex) is 92-94%. 5-year survival for patients on long-term dialysis has been shown to be either longer or shorter than patients with cancer, depending on the type of malignancy in an Italian registry of patients on dialysis. (Figure 1).
The range of the expected life span in the United States Renal Data System (USRDS) report was approximately 8 years for patients on dialysis 40 – 44 years of age and approximately 4.5 years for those 60 – 64 years of age. Let’s take a look at a few factors that have been associated with survival of the dialysis population:
1. Patient Demographics
As expected, survival for patients on dialysis declines with increasing age. Males younger than 45 years do better than females within the same age group. However, males have a lower adjusted mortality rate once above the age of 65.
Mortality rates among different races are not constant at all age groups, but overall, Asian-Americans and African-Americans have a better survival rate as compared to Caucasian patients.
2. Dialysis Vintage
The mortality rate of patients with ESKD also depends on the time since initiation of dialysis. For hemodialysis patients, there is a drop in the mortality rate initially which reaches its lowest point during Year 2, after which it continually rises. In patients receiving PD, we do not see this dip, rather the rate increases after initiation.
Despite the decrease in mortality in patients on HD by year 2, the first 120 days remain a period of high risk for patients who are starting HD. This was reported by Robinson and colleagues who examined all-cause mortality rates from patients receiving HD using data from the ongoing Dialysis Outcomes and Practice Patterns Study (DOPPS). This “high-risk period” after dialysis initiation is not seen in patients receiving PD and may be a result of patient selection (for PD).
3. Burden of Cardiovascular Disease
Patients with ESKD have a significant burden of cardiovascular disease which is much higher than that of the general population. Coronary artery disease is the most common cardiac condition found in patients with ESKD patients, with CVD as the leading cause of death for patients receiving dialysis (Figure 2).
4. Dialysis Modality: HD vs PD
There is a lack of good data that supports one modality over the other.
Previous observational data had favored PD in terms of mortality in the first years of treatment – but after 2 years, the survival advantage switches to HD. This is explained by the better preservation of residual kidney function initially in patients receiving PD followed by the loss of ultrafiltration capacity in the later years. On the other hand, the inclusion of sicker patients and urgent starts may bias against HD early in the treatment course because they have a much higher initial mortality rate and these sicker patients are treated almost exclusively with HD. More recently, a cohort study showed no difference in survival between this patients.
In summary, overall mortality is 10-20 times higher than the general population for patients receiving dialysis. The risk is greatest during the first 3 months after starting dialysis. Annual mortality is around 9% per year with 40-50% 5-year survival. The main cause of death in patients receiving dialysis is cardiovascular disease, followed by infectious complications. Thus far, studies have shown comparable outcomes for HD and PD.
Post written by:
Dr. Aldo Rodrigo Jimenez Vega (@aldorodrigo)