Functional status and heart rate variability in end-stage liver disease patients: association with nutritional status

Muscle dysfunction and reduced heart rate variability (HRV) are common in patients with advanced liver disease, and both are related to poor outcomes. Malnutrition is also highly prevalent in these patients, however, the association between the malnutrition and HRV has not yet been assessed. The aim of this study was to evaluate the short-term HRV, functional and nutritional statuses in patients with advanced liver disease.

The nutritional and functional statuses were determined by subjective global assessment, handgrip strength (dynamometer, JAMAR) and gait speed during a 6-minute walk text (6MWT), respectively. The cardiac workload index (CWI) was used to evaluate the cardiac response to the 6MWT. The time domain (SD of all normal-to-normal intervals [SDNN]) and very-low, low-, and high-frequency domains of short-term HRV were evaluated with RS800 CX (Polar, Finland) and Cardioseries software (Brazil).

The study evaluated 42 patients with liver disease (62% men) and malnutrition was found in 62% of this population. The malnourished participants presented with reduced functional status, 41% decreased SDNN, and 14% greater CWI compared with well-nourished individuals (P < 0.05). Additionally, the CWI was negatively associated to SDNN (r = 0.414; P < 0.05) and gait speed (r = 0.598; P < 0.05), especially in malnourished individuals (r = 0.650; P < 0.05). These data indicate that malnourished patients with liver disease have higher cardiovascular risk related to reduced functional status, which may be associated to poor outcomes during the course of the disease before and after transplant. Another relevant aspect is that the 6MWT associated to HRV could be a useful tool to screen liver disease patients who have a higher risk for cardiovascular complications.