Are preoperative obesity and cachexia risk factors for post heart transplant morbidity and mortality: A multi-institutional study of preoperative weight-height indices

Background: The relationship between pre-transplant body weight and post-tr ansplant outcome has only recently been identified using a single, indirect measure of weight (percent ideal body weight [PIBW]). The literature is eq uivocal regarding which index is the better indicator of body weight. The p urpose of this study was to determine (1) if pre-heart transplant body weig ht, measured by body mass index (BMI) and PIBW, is associated with post-hea rt transplant morbidity and mortality and (2) if patient gender, age, and e tiology of heart disease affect this association. Methods: The sample included 4,515 patients who received a heart transplant from January 1, 1990-December 31, 1995 at 38 institutions participating in the Cardiac Transplant Research Database (CTRD). Patients were divided int o groups according to their BMI and PIBW. Data were described using frequen cies, measures of central tendency, Pearson correlation coefficients, strat ified actuarial analyses and log rank tests for comparisons, and a multivar iable risk factor analysis in the hazard domain. Results: For all patients (n = 4,515), being <80% or >140% of IBW before he art transplant was a risk factor for increased mortality after heart transp lant. The association between pre-heart transplant PIBW and post-heart tran splant survival was affected by gender, age, and etiology of heart disease. In males, a higher PIBW was a significant risk factor for death early afte r transplant (p = .0003). Although not significant, there was a trend for a higher PIBW being a risk factor for death in females throughout the post t ransplant period (p = .07). No differences in cause of death were found for PIBW and BMI. In male and female recipients <55 years, being overweight pr e-heart transplant was a risk factor for infection. In patients with pre-tr ansplant ischemic heart disease, the greatest risk for infection was found in patients who were >140% of IBW. Pre-heart transplant BMI and PIBW were n ot associated with acute rejection or cardiac allograft arteriopathy after transplant. Conclusions: In conclusion, being cachectic or obese preoperatively is asso ciated with decreased survival in all patients after heart transplantation. Being obese preoperatively is associated with increased infection after he art transplant in males and females <55 years and in patients with ischemic heart disease. Of the 2 indices of body weight used in this study, percent ideal body weight appears to be the better predictor of future morbidity a nd mortality following heart transplantation.