Weight gain, overweight and obesity in solid organ transplantation—a study protocol for a systematic literature review

BACKGROUND Overweight and obesity, which have a substantial impact on health in the general population, have similar prevalence in solid organ transplant recipients but carry even more serious ramifications. As this group's use of immunosuppressive medication increases the risk for comorbidities, e.g. metabolic syndrome and cardiovascular disease, the prevention of additional risk factors is vital. This systematic review will be the first to summarize the issue of weight gain, overweight and obesity concurrently within and across solid organ transplantation. The three research questions relating to solid organ transplantation are the following: (1) What are the prevalence and evolution of overweight and obesity from pre- to post-transplant?; (2) Which pre- and post-transplant risk factors are associated with post-transplant weight gain, overweight or obesity? and (3) Which post-transplant patient outcomes and comorbidities are associated with pre- and post-transplant weight gain, overweight and obesity? METHODS/DESIGN MEDLINE via PubMed, The Cochrane Library, Cumulative Index to Nursing and Allied Health (CINAHL), PsycINFO and Excerpta Medica DataBase (EMBASE) will be searched for original quantitative studies in adult liver, heart, lung or kidney transplant patients. Topics of interest will be the prevalence and evolution of overweight and obesity over time, risk factors associated with changes in weight or body mass index (BMI), overweight and obesity, and the relationship of weight or BMI with post-transplant outcomes and comorbidities. Screening of titles and abstracts, full-text reading and data extraction will be divided between three researchers. Researchers will cross-check one another's screening decisions for random samples of studies to adhere as closely as possible to the recommendations of The Cochrane Collaboration. For quality assessment, a purpose-adapted 19-item instrument will be used. Effect sizes will be calculated for relationships investigated in a minimum of five studies. Random effects meta-analysis with moderator analyses will be conducted if applicable. DISCUSSION This systematic review will comprehensively synthesize the existing evidence concerning weight gain, overweight and obesity in solid organ transplantation in view of magnitude, influencing factors and associations with patient outcomes and comorbidities. The results can fuel the development of interventions to prevent weight gain in the solid organ transplant population. SYSTEMATIC REVIEW REGISTRATION PROSPERO CRD42014009151.