What should we expect from optimal dialsyis?

By Bill Peckham

On Friday RenalWEB linked to an advance online abstract from Kidney International: Nocturnal Hemodialysis Does Not Improve Overall Measures of Quality of Life Compared to Conventional Hemodialysis. The headline raised a number of questions which the abstract doesn't answer. I wrote the contact for the paper, Dr. Manns who helped provide context by pointing to a paper published in JAMA, September 19, 2007—Vol 298, No. 11: Effect of Frequent Nocturnal Hemodialysis vs Conventional Hemodialysis on Left Ventricular Mass and Quality of Life, which is available online. Both articles are based on the same randomized control trial.

This new article goes into the quality of life measures more completely but I think the author's comments from the September 2007 paper still stand:

While our study could be criticized for measuring surrogate end points that have not been validated in ESRD, it is important to note that we also measured HRQOL, an important outcome in a chronic disease such as ESRD. We found no difference in the primary quality of life measure comparing change from baseline to 6 months, but noted statistically and clinically significant improvements in 2 of 4 kidney-specific measures of quality of life comparing change from baseline to 6 months. For our primary quality of life end point, we found that scores appeared to deteriorate consistently over time in patients randomized to conventional hemodialysis and be maintained or increase slightly in patients randomized to nocturnal hemodialysis. These changes, which were observed at baseline and before exposure to the intervention, may have resulted from the subjective nature of "overall" quality of life measures such as the EQ-5D index score, and might represent an artificial anticipatory effect, rather than a true effect from nocturnal hemodialysis per se. It is interesting to note that these results (a slight increase in the quality of life in nocturnal hemodialysis patients and a reduction in quality of life in control patients) was also noted in a previous nonrandomized report³¹ and warrants further study, given that our study was not powered for quality of life outcomes. These limitations acknowledged, the magnitude of the change noted in utility scores comparing 6 months and randomization is similar to the mean change observed in dialysis patients who receive a kidney transplant, suggesting this difference in quality of life could be very clinically significant.³²

The Kidney International paper should be out in a few weeks (hopefully it will be freely available) but I'm not sure what will change. I think the authors will still concede their study's shortcomings. Measuring Quality of Life is a tricky business.

The Kidney Disease Quality of Life Short Form is available online (PDF link). Reading through the self administered survey I asked myself how many answers would I expect to change after six months of daily home hemo? I don't go to the effort of getting a high dose of hemodialysis for the impact on my life today, I choose high dose hemodialysis for the benefit it provides over time. I agree with Peter that followup studies over years would show variation. The longer I do high dose dialysis the better it looks.

Thinking about this abstract and how it has been received brought to mind my Thanksgiving post. We should be careful to not over sell any renal replacement therapy. I absolutely believe that frequent nocturnal dialysis is the safest, healthiest form of dialysis. Of the available options, daily nocturnal most completely treats CKD5. I think it can make having CKD5 less of a burden but it will still be a burden, it is still a hard row to hoe. Optimal dialysis is good but it's not that good.