Using Renal Transplantation to Evaluate a Simple Approach for Predicting the Impact of End-Stage Renal Disease Therapies on Patient Survival: Observed/Expected Life Span Bryan N. Becker, MD, Yolanda T. Becker, MD, Thomas J. Pintar, MD, Bradley H. Collins, MD, John D. Pirsch, MD,Aaron Friedman, MD, Hans W. Sollinger, MD, PhD, and Peter C. Brazy, MD ● The effectiveness of therapy for a chronic disease can be assessed by evaluating the length of time that a patient survives after receiving treatment. We used a novel means for measuring the effectiveness of renal replacement therapy for patients with end-stage renal disease (ESRD): the ratio of observed life span divided by expected life span. This ratio incorporated observed life span for patients from the time of ESRD and expected life span based on state-specific life-table analyses. A total of 3,782 individuals with ESRD were analyzed (average follow-up, 14.2  4.9 years); 3,192 patients in that group received a kidney transplant at some point during their course of ESRD. For each patient, we determined a curve of observed/expected life span. Separate patient groups were analyzed to determine the median population observed/expected life span or the percentage of patients who reached 0.5 observed/ expected life span. Younger transplant recipients (F21 years) had a median observed/expected life span of 67%, significantly greater than the median observed/expected life span for those aged 21 to 40 years (49%; P  0.01) and 41 to 60 years (47%; P  0.01). Surprisingly, 57% of the patients aged older than 60 years reached their median observed/expected life span (P  0.02 versus F21 years; P  not significant against all others). A Cox proportional hazards model identified era of immunosuppression (hazards ratio, 0.32) and atherosclerotic vascular disease– related ESRD (hazards ratio, 2.07) as significant variables influencing patient survival and observed/expected life span. This simple ratio is easy to use and may be a helpful tool for assessing the survival benefits of risk-factor modifications and therapeutic advances in transplantation and ESRD care.  2000 by the National Kidney Foundation, Inc. INDEX WORDS: Kidney transplantation; survival; life span; mortality. P ATIENTS WITH end-stage renal disease (ESRD) have poor overall survival com- pared with age-matched individuals in the gen- eral population and even compared with individu- als with other chronic illnesses. 1,2 For example, a man who starts hemodialysis at the age of 52 years has an average life expectancy of 5.35 years, 3 similar to the life span of a similarly aged patient diagnosed with colorectal carcinoma. 4 This represents approximately 20% of the life expectancy of a man this age in the general population. One goal of renal replacement therapy is to provide patients with life expectancy as near to normal as possible. However, one must consider that a person’s normal life expectancy depends on his or her age and other demographic charac- teristics, such as race, sex, and place of resi- dence. Thus, a measure of the effectiveness of renal replacement therapy is the length of actual patient survival in comparison to the average life span of an age-matched healthy individual from the same population. Renal transplantation is the form of renal replacement therapy that restores the greatest degree of normal renal function. Historically, a variety of factors, including graft failure and immunosuppression-related complications, lim- ited the extent to which renal transplantation could restore patients with ESRD to normal survival. Studies from the pre–cyclosporine (CsA) era (before 1984) were unable to show a substan- tial survival advantage for kidney transplantation compared with dialysis patients who were on transplant waiting lists. 5,6 However, advances in immunosuppression, HLA matching, and organ preservation have fueled an increase in graft survival. The cadaveric graft survival rates now approximate 90% at 1 year 7 and 70% at 5 years. 8 Moreover, additional studies 7-10 suggest that kid- ney transplantation reduces the mortality of pa- tients with ESRD. These reports are encouraging. However, it must be kept in mind that patient outcomes are From the Departments of Medicine, Pediatrics, and Sur- gery, University of Wisconsin, Madison, WI. Received February 24, 1999; accepted in revised form October 15, 1999. Supported in part by grant no. DK-02420 from the Na- tional Institutes of Health (B.N.B.). Address reprint requests to Bryan N. Becker, MD, Divi- sion of Nephrology, University of Wisconsin Hospital and Clinics, H4/510 Clinical Science Center, 600 Highland Ave, Madison, WI 53792. E-mail: bnb@medicine.wisc.edu  2000 by the National Kidney Foundation, Inc. 0272-6386/00/3504-0011$3.00/0 American Journal of Kidney Diseases, Vol 35, No 4 (April), 2000: pp 653-659 653