Impact of calorie intake and refeeding syndrome on the length of hospital stay of patients with malnutrition: a systematic review and meta-analysis

The decrease of nutritional status has affected one-third hospitalized patients, while there is no widely used definition of malnutrition. Refeeding syndrome is a severe complication of refeeding in people with malnutrition, it includes a series of electrolyte disorders and clinical symptoms. Further research is warranted to determine whether refeeding syndrome prolongs the length of stay, and to verify the effect of different energy intakes during refeeding on the length of stay in people with malnutrition. Our review aimed to explore the effects of refeeding syndrome and initial calorie intake on the length of stay in patients with malnutrition. This study aids the understanding of clinical nutrition strategies to prevent and treat refeeding syndrome.PubMed, Embase, Cochrane Library, Web of Knowledge, and two Chinese databases were systematically searched until October 2021. Controlled studies of patients' refeeding process with the outcome of length of stay were included. Effect sizes were expressed as 95% confidence intervals (CIs) and calculated using random-effects models.Eighteen studies involving 3868 participants were included in our review. The pooled length of stay of 2965 patients with refeeding syndrome in 11 studies was 25.55 (95% CI, 20.20-30.90) days. The pooled impact of refeeding syndrome on length of stay of 2634 patients in 10 studies was weighted mean difference (WMD) = 2.91 (95% CI, -0.18 - 6.00; P = 0.065) days. The pooled effect of higher calorie intake of 1234 patients in 8 studies was WMD = -3.04 (95% CI, -5.10 to -0.99, P = 0.003) days.The average length of stay in patients with refeeding syndrome was 25.55 days with a very high heterogeneity between studies. Refeeding syndrome affects the length of stay in part of, but not all, patients. In the present review, we concluded that higher initial calorie intake may help shorten the length of stay in patients with malnutrition. More well-designed randomized controlled trials are needed to explore the effect of calorie intake during refeeding.