UNOS tracks graft and patient survival rates for each type of organ transplant at all the transplant centers in the country. For each hospital UNOS calculates the actual survival rates for 6 months and yearly. UNOS also calculates what the expected survival rate is for each type of transplant, based on patient characteristics such as age and donor characteristics such as whether the organ came from a living donor or a cadaver donor.
Many factors influence a transplant center's actual survival rate.
It can be misleading if used as a sole indicator of quality because it is due to both the effectiveness or quality of the services at a hospital and the characteristics of the patients that the hospital is treating. For example, some transplant centers perform transplants on much sicker patients than others. This hospital may have an excellent transplant program, but its actual survival rates would probably be lower than those of other hospitals. Although UNOS can account for some of these differences among patients in its calculations, all of the factors that affect survival are not understood, and many characteristics known to affect survival are not measurable. Therefore, the expected survival rates at best adjust only partially for the differences between hospitals regarding the kinds of patients they treat.