Racial variation in medical outcomes among living kidney donors

BACKGROUND: Data regarding health outcomes among living kidney donors are lacking, especially among nonwhite persons. METHODS: We linked identifiers from the Organ Procurement and Transplantation Network (OPTN) with administrative data of a private U.S. health insurer and performed a retrospective study of 4650 persons who had been living kidney donors from October 1987 through July 2007 and who had post-donation nephrectomy benefits with this insurer at some point from 2000 through 2007. We ascertained post-nephrectomy medical diagnoses and conditions requiring medical treatment from billing claims. Cox regression analyses with left and right censoring to account for observed periods of insurance benefits were used to estimate absolute prevalence and prevalence ratios for diagnoses after nephrectomy. We then compared prevalence patterns with those in the 2005–2006 National Health and Nutrition Examination Survey (NHANES) for the general population. RESULTS: Among the donors, 76.3% were white, 13.1% black, 8.2% Hispanic, and 2.4% another race or ethnic group. The median time from donation to the end of insurance benefits was 7.7 years. After kidney donation, black donors, as compared with white donors, had an increased risk of hypertension (adjusted hazard ratio, 1.52; 95% confidence interval [CI], 1.23 to 1.88), diabetes mellitus requiring drug therapy (adjusted hazard ratio, 2.31; 95% CI, 1.33 to 3.98), and chronic kidney disease (adjusted hazard ratio, 2.32; 95% CI, 1.48 to 3.62); findings were similar for Hispanic donors. The absolute prevalence of diabetes among all donors did not exceed that in the general population, but the prevalence of hypertension exceeded NHANES estimates in some subgroups. End-stage renal disease was identified in less than 1% of donors but was more common among black donors than among white donors. CONCLUSIONS: As in the general U.S. population, racial disparities in medical conditions occur among living kidney donors. Increased attention to health outcomes among demographically diverse kidney donors is needed. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases and others.

Predicting long-term graft survival in adult kidney transplant recipients

The ability to accurately predict a population′s long-term survival has important implications for quantifying the benefits of transplantation. To identify a model that can accurately predict a kidney transplant population′s long-term graft survival, we retrospectively studied the United Network of Organ Sharing data from 13,111 kidney-only transplants completed in 1988- 1989. Nineteen-year death-censored graft survival (DCGS) projections were calculated and com-pared with the population′s actual graft survival. The projection curves were created using a two-part estimation model that (1) fits a Kaplan-Meier survival curve immediately after transplant (Part A) and (2) uses truncated observational data to model a survival function for long-term projection (Part B). Projection curves were examined using varying amounts of time to fit both parts of the model. The accuracy of the projection curve was determined by examining whether predicted sur-vival fell within the 95% confidence interval for the 19-year Kaplan-Meier survival, and the sample size needed to detect the difference in projected versus observed survival in a clinical trial. The 19-year DCGS was 40.7% (39.8-41.6%). Excellent predictability (41.3%) can be achieved when Part A is fit for three years and Part B is projected using two additional years of data. Using less than five total years of data tended to overestimate the population′s long-term survival, accurate prediction of long-term DCGS is possible, but requires attention to the quantity data used in the projection method

Three-year post-transplant medicare payments in kidney transplant recipients: Associations with pre-transplant comorbidities

Little is known about the influence of pre-transplant comorbidities on post-transplant expenditures. We estimated the associations between pre-transplant comorbidities and post-transplant Medicare costs, using several comorbidity classification systems. We included recipients of first-kidney deceased donor transplants from 1995 through 2002 for whom Medicare was the primary payer for at least one year pre-transplant (N = 25,175). We examined pre-transplant comorbidities as classified by International Classification of Diseases (ICD-9-CM) codes from Medicare claims with the Clinical Cla-ssifications Software (CCS) and Charlson and Elixhauser algorithms. Post-transplant costs were calcu-lated from payments on Medicare claims. We developed models considering Organ Procurement and Transplantation Network (OPTN) variables plus: 1) CCS categories, 2) Charlson, 3) Elixhauser, 4) num-ber of Charlson and 5) number of Elixhauser comorbidities, independently. We applied a novel regression methodology to account for censoring. Costs were estimated at individual and population levels. The comorbidities with the largest impact on mean Medicare payments included cardiovascular disease, ma-lignancies, cerebrovascular disease, mental conditions and functional limitations. Skin ulcers and infec-tions, rheumatic and other connective tissue disease and liver disease also contributed to payments and have not been considered or described previously. A positive graded relationship was found between costs and the number of pre-transplant comorbidities. In conclusion, we showed that expansion beyond the usually considered pre-transplant comorbidities with inclusion of CCS and Charlson or Elixhauser comorbidities increased the knowledge about comorbidities related to augmented Medicare payments. Our expanded methodology can be used by others to assess more accurately the financial implications of renal transplantation to Medicare and individual transplant centers

Cardiac Evaluation before Kidney Transplantation: A Practice Patterns Analysis in Medicare-insured Dialysis Patients

Background and objectives: Evaluation for ischemic heart disease (IHD) is a nonstandardized practice before kidney transplantation. We retrospectively studied pretransplant cardiac evaluation (CE) practices in a national sample of renal allograft recipients

The Interplay of Socioeconomic Status, Distance to Center, and Interdonor Service Area Travel on Kidney Transplant Access and Outcomes

Background and objectives: Variation in kidney transplant access across the United States may motivate relocation of patients with ability to travel to better-supplied areas

Novel Methods for Tracking Long-Term Maintenance Immunosuppression Regimens

Background and objectives: Accurate assessment of the use of immunosuppressive medications is vital for observational analyses that are widely used in transplantation research. This study assessed the accuracy of three potential sources of maintenance immunosuppression data