In my opinion, much of the cause may well be related to the inflammatory process in addition to the more obvious causes of poor lipid control, poor BP, and hypervolemia. I would argue that we probably are. Consider the following. For a given amount of dialysis, a small person will have a higher URR than a large one. It's the same.
Data show that physically small patients had the highest URRs and also have the highest death rate.
Therefore, low lean body mass and a low V in a small patient may contribute to both a higher URR and a greater chance of dying. It's not the URR causing the higher mortality. It's the low body mass. When this was discovered, it was perhaps our first hint that body mass has survival implications. Joel Kopple, MD, showed that people who were taller and heavier do better on dialysis.