Due to the increasing energy expenditure, hospitalized patients with chronic obstructive pulmonary disease (COPD) with respiratory failure are susceptible to nutritional risks [1]. It was reported that nutritional risks are associated with more treatment failures, higher incidence of complications and poorer prognosis [1,2]. Nutritional risk screening 2002 (NRS 2002) is so far the only evidence-based tool to assess the nutritional status, which was issued by European Society for Clinical Nutrition and Metabolism (ESPEN) [3].
