Changes in appetite related gut hormones in intensive care unit patients: a pilot cohort study

Sixteen ICU patients (60 ± 4.7 years, body mass index (BMI) 28.1 ± 1.7 kg/m2 (mean ± standard error of the mean)) underwent fasting blood sample collections on days 1, 3, 5, 14, 21 and 28 of their stay at Hammersmith and Charing Cross Hospitals. Changes in appetite and biochemical and anthropometric markers of nutritional status were recorded. A comparison was made to a group of 36 healthy volunteers matched for age and BMI (54.3 ± 2.9 years, p = 0.3; BMI 25.8 ± 0.8 kg/m2 p = 0.2).Compared to healthy subjects, ICU patients exhibited a significantly lower level of ghrelin (day one 297.8 ± 76.3 versus 827.2 ± 78.7 pmol/l, p < 0.001) during their stay in the ICU. This tended to rise to the normal level during the last three weeks of hospital stay. Conversely, ICU patients showed a significantly higher level of PYY (day one 31.5 ± 9.6 versus 11.3 ± 1.0 pmol/l, p < 0.05) throughout their stay in the ICU and on the ward, with a downward trend to the normal level during the last three weeks of stay.Results from our study show high levels of PYY and low levels of ghrelin in ICU patients compared to healthy controls. There appears to be a relationship between the level of these gut hormones and nutritional intake.Impaired appetite is a common feature of illness. A recent review suggested that 10% to 40% of adult patients admitted to hospital exhibit some level of nutritional depletion [1], with much weight loss, occurring over the period of hospitalisation [2]. This is a matter of particular concern for certain categories of patients. Patients in intensive care units (ICUs) are a vulnerable group. One report suggested 55 out of 129 patients admitted to ICUs were already suffering from malnutrition [3]. Their nutritional status further declines during the intensive care and also after their ICU stay [3]. This study noted that despite 20 years of intense awareness, malnutrition was still highly prevalent in hospitalised patients and this continues to affect patients' outcomes.