Systematic review of prognostic value of cardiorespiratory fitness in patients with cirrhosis.

BACKGROUND

Cirrhosis is associated with significant risk of comorbidity and early mortality. Low physical function is common in patients with cirrhosis and could predict prognosis. Cardiorespiratory fitness (CRF), determined by maximal exercise with gas exchange measurement, has proven to predict the risk of mortality and disability in other chronic diseases. In patients with cirrhosis, it could help to inform prognostic stratification to improve care and management in clinical practice. This systematic review aims to determine the association between CRF (VO2Peak, percentage of predicted VO2Peak, Anaerobic Threshold (AT)) and mortality prediction, as well as morbidity prediction in cirrhosis.

METHODS

We reviewed the main electronic databases (PubMed, Scopus, Embase, Google Scholar) for all relevant literature running up to April 2024. Two independent researchers applied predefined inclusion criteria to assess articles for eligibility, and ultimately included 15 studies (seven studied mortality alone, six morbidity alone and two both).

RESULTS

Eight out of nine studies reported CRF variables as a predictor of mortality, and eight studies found that CRF predicted occurrence of events associated with morbidity (sepsis, length of hospital stay and length of stay in critical care). VO2Peak below 17 mL.min-1.kg-1 (5 METS) is an independent predictor of mortality and morbidity. AT can be reached by the large majority of patients with cirrhosis after a moderate-intensity physical exercise, lasts 15 minutes, can be repeated and could be the best choice. AT inferior to 9 ml.min-1.kg-1 or 2.5 METS (metabolic-equivalent tasks defined as the amount of oxygen consumed while sitting at rest) can predict mortality risk and 10 ml.min-1.kg-1 (3 METS) the sepsis risk.

CONCLUSIONS

VO2Peak below 17 mL.min-1.kg-1 (5 METS) or an AT under 9 mL.min-1.kg-1 (2.5METS), consistently indicate worse outcomes. Assessing CRF could help to improve mortality and morbidity prediction and AT seems to be the best tool to predict the prognosis in patients with cirrhosis.