Relationship between body mass index and mortality in adults on maintenance hemodialysis: a systemic review*

Abstract

Objective: The primary objective of this systematic review was to determine the relationship between body mass index (BMI) and all-cause and cardiovascular mortality. Design: Systematic review of primarily observational studies. Patients: Adult patients from all gender, race, or ethnic groups on maintenance hemodialysis. Methods: Medline, Science Citation Index, Academic Search Premier, Cochrane Library, and Embase electronic databases covering the period 1966 to December 2008 were searched with the help of a qualified librarian. Reference lists of included papers and collections also were searched. Each study was reviewed by 2 independent reviewers who also performed the data extraction from full papers. Differences between reviewers were resolved by consensus or by a third reviewer in the case of disagreements. The quality of studies selected for inclusion in the systematic review was also assessed by 2 independent reviewers. Main Outcomes: BMI and mortality. Results: Eighteen studies (60%) reported a significant inverse relationship between all-cause mortality and BMI. This inverse relationship was more prevalent in older patients, larger retrospective studies, and studies that did not adjust for inflammation. On the other hand, 57% of the 7 studies reporting on cardiovascular mortality found no significant relationship with BMI. Conclusions: This systematic review shows evidence of an inverse relationship between BMI and all-cause mortality in adult patients on maintenance HD, especially in older patients, but the relationship with cardiovascular mortality is less clear.