Background: Inadequate protein intake is associated with poor physical functioning and suboptimal recovery in hospitalised older adults. Despite standard dietetic care, dietary protein intakes falls well below the recommended levels. To address this problem, we developed an intensified trans-sectorial dietetic intervention that targets hospitalised older adults. This study aims to evaluate its impact on physical functioning and dietary protein intake during and post hospitalisation.

Methods: This multicentre individually randomised controlled trial was conducted in five hospitals from January 2021 until December 2022. Hospitalised older adults, aged ≥55 years and at risk of malnutrition were randomised to receive regular care (CON) or intensive dietetic intervention (INT). The intervention consisted of personalized, intensive care, including trans-sectorial guidance by trained dietitians, increased consultations, and supportive materials focused on protein intake. Additionally, the intervention emphasized engagement in dietary behaviour and physical activity during hospitalisation and continued for three months post-discharge. The primary outcome was change in physical functioning measured by the Short Physical Performance Battery (SPPB) from admission to three months post-discharge, analysed with linear mixed models for repeated measures. Secondary outcomes included protein intake, body composition, muscle strength, physical activity, activities of daily living, fear of falling, pain, fatigue, appetite and quality of life.

Results: A total of 76 hospitalised older adults were included in the study of which 38 were in CON and 38 received INT. The overall drop-out was 30 % (CON 26 %; INT 34 %). The participants had a median age 73 y (Inter Quartile Range: 62-78 y) with 50 % females. Overall, Physical functioning improved from 6 points (IQR: 1-9 points) at baseline to 9 points (IQR: 7-11) at three months post-discharge (p < 0.0001). Likewise, protein intake increased from 0.8 g/kg bodyweight (IQR: 0.6-1.0) to 1.0 g/kg bodyweight (IQR: 0.8-1.2) (p < 0.0001). There were no significant differences between intervention and control group. All secondary outcomes improved over time, except for fear of falling, leg extension strength, and body composition, with no significant differences between intervention and control group.

Conclusions: Hospitalised older patients improved their physical functioning and protein intake after three months post-discharge, although the majority not to recommended levels. No effects of the intensive dietetic treatment could be detected due to low intervention adherence and a small sample size. Future research should be conducted with an intervention consisting of a strong combination of nutritional support and exercise with a successful implementation and a flexible study design catered to the needs of the older patient.

Trial registration: Landelijk Trial Register (NL8041; NL72069.029.19) www.onderzoekmetmensen.nl; registered 2019-09-23; covering all WHO Trial Registration Data Set items.