Malnutrition is associated with health adverse outcomes such as higher risk of mobility disability, falls and, fractures and higher mortality. Malnutrition had been defined as "a state resulting from lack of intake or uptake of nutrition that leads to altered body composition (decreased fat free mass) and body cell mass leading to diminished physical and mental function and impaired clinical outcome from disease". In 2018, the European Society for Clinical Nutrition and Metabolism (ESPEN) revisited nutrition and nutrition-related conditions definitions in the ESPEN guidelines on definitions and terminology of clinical nutrition based on the findings of the last decades. Nutrition disorders and nutrition related conditions were divided in 5 categories: Malnutrition/undernutrition, sarcopenia and frailty, overweight and obesity, micronutrients abnormalities, and refeeding syndrome. The definition of malnutrition based on the Global Leadership Initiative on Malnutrition (GLIM) criteria is globally accepted by de scientific community since this was launched in 2019. The presence of at least one phenotypic (i.e., nonintentional weight loss, low body mass index or low muscle mass) and one etiologic criterion (i.e., reduced food intake or inflammation) were required to define malnutrition.

Malnutrition is a common pathological condition in older adults that can further influence and aggravate health-related muscle decline. Sarcopenia is known as a natural progressive decline in skeletal muscles occurring with age, with an age-related decline in muscle strength. According to the criteria published in 2019 by the European Working Group on Sarcopenia in Older People (EWGSOP2), this process is defined by the presence of low muscle strength and low muscle mass.

Patients in acute care are likely to present higher stay and risk of mortality. However, the mortality have rarely been applied in acute care, due to difficulties to administer Dual X-ray Absorptiometry (DXA), the gold standard method for muscle mass in acute care. Pragmatic approaches to assess nutrition and nutrition-related condition are urgently needed to provide better quality of care in clinical practice in geriatric medicine.

The primary objective of this study is to determine the impact of nutrition disorders and nutrition-related conditions at baseline (admission in hospitalization) on the all-causes mortality risk in hospitalized older people.

Secondarily, this study evaluates their impact on other health adverse outcomes: falls, fractures, rehospitalization, institutionalization, all-cause admission in intensive care, length of hospital stay, length of ventilation and USI stay.

Finally, the diagnostic performance indicators of the Mini Nutritional Assessment (MNA-SF) and the Geriatric Nutritional Risk Index (GNRI) for malnutrition assessment following the GLIM criteria were calculated.

Inclusion Criteria:

• Patients aged ≥60 and over admitted to the geriatric healthcare unit and/or the COVID-19 unit of the CHU Brugmann Hospital, between 01/01/2016 and 12/10/2021.
• Patients who had the assessment of nutrition disorders and/or nutrition related conditions available during their hospital admission.

Exclusion Criteria:

- No exclusion criteria based on demographical or medical data were applied.

Patients aged ≥60 and over admitted to the geriatric healthcare unit and/or the COVID-19 unit of the CHU Brugmann Hospital, between 01/01/2016 and 12/10/2021.