The relationship between subjective appetite sensations, markers of inflammation and appetite in dialysis patients

Background: Poor appetite is a marker of morbidity and mortality in haemodialysis patients, making it an important area for research. Visual analogue scales (VAS) can capture a range of subjective sensations related to appetite (such as hunger, desire to eat or fullness), but have not been commonly used to measure appetite in dialysis patients. The present study aimed to explore the association between retrospective ratings of appetite using VAS and a range of clinical variables, as well as biomarkers of appetite in haemodialysis patients. Methods: Twenty-eight haemodialysis patients [mean age 61 ± 17 years, 50% male, median dialysis vintage 19.5 (4-101) months] rated their appetite using VAS for hunger, fullness and desire to eat and a five-point categorical scale measuring general appetite. Blood levels of the appetite peptides leptin, ghrelin and peptide YY were also measured. Results: Hunger ratings measured by VAS were significantly (P < 0.05) correlated with a range of clinical, nutritional and inflammatory markers: age (r = -0.376), co-morbidities, (r = -0.380) Patient-Generated Subjective Global Assessment score (r = -0.451), weight (r = -0.375), fat-free mass (r = -0.435), C-reactive protein (r = -0.383) and intercellular adhesion molecule (r = -0.387). There was a consistent relationship between VAS and appetite on a five-point categorical scale for questions of hunger, and a similar trend for desire to eat, but not for fullness. Neither method for measuring subjective appetite correlated with appetite peptides. Conclusions: Retrospective ratings of hunger on a VAS are associated with a range of clinical variables and further studies are warranted to support their use as a method for measuring appetite in dialysis patients.