Abstract:
Inpatient glycaemia describes changes in blood glucose concentration during hospitalisation and has been associated with short-term outcomes across a range of acute disease settings. Variations in blood glucose may explain the physiological response to injury and assist with reducing adverse outcomes during hospitalisation, however, the most useful measures of glucose variability in the acute disease setting remain unclear. In addition, whether inpatient glycaemia is associated with adverse outcomes after hospital discharge is poorly investigated. The first aim of this thesis was to investigate the usefulness of several variability measures of inpatient glycaemia in predicting the risk of developing oral feeding intolerance (OFI) during acute pancreatitis (AP), an exemplar of acute and critical illness. Secondly, this thesis aimed to systematically review and meta-analyse clinical studies in acute and critical illness that investigated the relationship between the degree of inpatient glycaemia and prevalence of new onset diabetes, as an example of a long-term outcome. The results of this thesis showed that certain variations in blood glucose concentration were associated with subsequent risk of developing OFI in patients with AP. In particular, mean blood glucose concentration and admission blood glucose concentration were significantly associated with OFI in multivariate analyses and could be useful predictors in the clinical setting. In addition, the meta-analysis found a stepwise increase in the prevalence of new onset diabetes with increasing degree of inpatient glycaemia. Patients with severe inpatient hyperglycaemia and no previous diabetes had the greatest risk, with 28% developing diabetes after hospital discharge. Future research should be directed towards exploring the usefulness of parameters of inpatient glycaemia in broader settings of acute and critical illness to determine the best predictor of adverse outcomes. Additionally, mechanistic and longitudinal prospective studies are warranted to investigate the pathogenesis of the observed changes and to explore whether controlling the variability of blood glucose can reduce the risk of both short- and long-term adverse outcomes in acute and critical illness.