Identifying reliable predictors of protein-energy malnutrition in hospitalized frail older adults: A prospective longitudinal study

Abstract

Background: Decreased food intake is a risk factor for relevant complications (e.g. infections, pressure ulcers), longer hospital stays, higher readmission rates, greater health care costs and increased patient mortality, particularly in frail hospitalized older adults who are malnourished or at risk of malnutrition. Nurses are called to improve this criticality, starting from accurately identifying malnourished patients at hospital admission and effectively monitoring their food intake.

Objectives: The primary aim was to identify reliable predictive indicators of reduced food intake at hospital admission. The secondary aims were to assess the adequacy of daily energy and protein intake and the impact of nutrient intake on patient outcomes.

Design: Prospective observational longitudinal study.

Setting: Internal Medicine Ward of an Academic Teaching University Hospital.

Participants: Acute older adults who were malnourished or at risk of malnutrition (Nutritional Risk Score-2002 ≥ 3, middle-upper arm circumference <23.5 cm or impaired self-feeding ability) at admission.

Methods: The effective energy and protein intake was monitored during the first 5 days of hospital stay by a photographic method and compared to the daily energy and protein requirement calculated by specific equations. Data on anthropometry, inflammation/malnutrition laboratory data and body composition (phase angle calculated using bioelectrical impedance analysis) were collected.

Results: Eighty-one subjects (age 81.5 ± 11.5 years) were enrolled. Mean energy intake was 669.0 ± 573.9 kcal/day, and mean protein intake was 30.7 ± 25.8 g/day. Over 60% of patients ingested ≤50% of their calculated energy and protein requirements: these patients were older (p = 0.026), had a lower middle-upper arm circumference (p = 0.022) and total arm area (p = 0.038), a higher C-reactive protein/albumin ratio and Instant Nutritional Assessment score (p < 0.01), and experienced longer hospital stays (p ≤ 0.04) and higher in-hospital and 30-day post-discharge mortality (p < 0.001). In the multivariate analysis, lower middle-upper arm circumference, higher C-reactive protein/albumin ratio, and impaired self-feeding at admission were independently associated with critically reduced energy and protein intake.

Conclusions: Middle-upper arm circumference, C-reactive protein/albumin ratio, and impaired self-feeding are easily obtainable indicators of impaired energy and protein intake and poor clinical outcomes. Such parameters should be adopted as screening criteria to assess the risk for critically reduced energy/protein intake in hospitalized older adults. These findings are relevant to improve clinical practice through the implementation of multidisciplinary strategies, given the adverse clinical outcomes related to hospital malnutrition.

Keywords: CRP-albumin ratio; Elderly; Feeding self-care; Hospital malnutrition; MUAC; Older adults; Reduced food intake.