Accuracy of predictive equations versus indirect calorimetry for the evaluation of energy expenditure in cancer patients with solid tumors – an integrative systematic review study

Cancer is one the principal causes of death, and is considered a health issue worldwide. Cancer patients are at high risk of malnutrition due to the disease and the treatment itself. Nutritional therapy is part of a multi-modal treatment and it is important to be aware of the patient's energy expenditure to aid in decision-making for dietotherapeutic prescription. Indirect Calorimetry (IC) is the gold standard method for measuring energy expenditure (EE); but due to its often high cost in clinical practise, equations that measure energy expenditure are usually used. Objectives: To perform an integrative systematic review, searching in the literature for how predictive equations of EE behave in relation to IC in cancer patients with solid tumors, considering the overall accuracy for cancer patients, the different tumor types, and the type of anti-cancer therapy applied. Methods: A review was carried out of systematic integrative type literature. The articles were searched for in three databases (Pubmed, Embase, and Web of Science) using descriptors accompanied by Boolean operators. Inclusion and exclusion criteria were determined, and the articles found went through selection, analysis and extraction of their results. Results: A total of 688 articles were identified that underwent a thorough selection, resulting in 15 studies that included in this review. In five studies, the results showed that predictive equations underestimated the EE of cancer patients; in three studies the EE was overestimated by predictive equations, and in seven studies predictive equations underestimated or overestimated the EE. The low accuracy of predictive EE equations was present regardless of tumor type and type of anti-cancer therapy received by patients. Conclusion: The predictive energy expenditure equations available to date are generally not in accordance with IC results for cancer patients with solid tumors, since these individuals present clinical situations or are exposed to factors that alter EE and are not considered in these equations. © 2019 European Society for Clinical Nutrition and Metabolism35121