Over 10,000 Americans receive kidney and pancreas-kidney transplants each year for the primary purpose of improving their quality of life. For most, this goal is quickly realized in the early postoperative period, and accompanies the sudden and dramatic correction of biological derangements associated with end-stage renal disease and diabetes. Some of the most severe biological derangements associated with both disease states are related to the autonomic nervous system which controls several critical body functions. Fortunately, autonomic function significantly improves following transplantation. Though the profound improvement in posttransplant quality of life would seem to be attributed to the correction of biological derangements such as those associated with autonomic function, this relationship has yet to be established. The purpose of this study is to explicate the biobehavioral linkages among changes in autonomic function and quality of life that occur following kidney and pancreas-kidney transplantation. Approximately 190 kidney and pancreas-kidney transplant recipients will be studied prior to and at six, twelve and twenty-four months after transplantation. Three questionnaires will quantify functional (Sickness Impact Profile), health related (Quality of Life Index), and psycho emotional (Adult Self-Image Scales) dimensions of quality of life. Autonomic function will be evaluated by state-of-the-art technologies measuring 1) vasomotor function by infrared photoplethysmography which quantifies total pulse amplitude, postural adjustment ratio, and reflex vasoconstriction, 2) cardiac function by electrocardiogram and blood pressure recordings which quantifies R-R interval variation, valsalva ratio, and postural change in systolic blood pressure, 3) gastric function by electrogastrography which quantifies rhythmicity of gastric contractions, and 4) autonomic balance by power spectral analysis of heart rate variability which quantifies adrenergic and cholinergic activity as well as circadian autonomic rhythmicity. Results of these tests will undergo statistical modeling and factor analysis to identify the contribution of autonomic-, demographic, and health-related characteristics to quality of life at various time intervals following transplantation. Extant quality of life research in transplantation has typically employed cross-sectional designs and has remained at a descriptive level. Our study moves to the explanatory level of inquiry in order to explicate the biobehavioral linkages responsible for improved posttransplant quality of life. Study at this level is particularly important in transplantation as it will contribute to our understanding of how transplantation alters quality of life. Knowledge of this nature will influence decisions regarding when transplantation should be undertaken during the course of end-stage organ disease in order to provide the greatest benefit, and will facilitate development of interventions designed to maximize posttransplant quality of life.
