An Epidemiological Investigation Into the Association Between Recent Stroke, Acute Coronary Syndrome or Pneumonia and Adverse Perioperative Outcomes Following Elective Non-cardiac and Cardiac Surgery

Previous studies have identified prior stroke, heart attack or current diabetes mellitus and anaemia as important risk factors for adverse outcomes following surgery. Recent heart attacks are associated with greater risks than older ones. While recent data suggests that newer strokes impart significantly greater risk than older strokes, there is a lack of concordance on the literature on this, despite the plausibility of the finding. Despite knowledge that prior pneumonia has long-term health risks, there is a lack of data on whether prior pneumonia influences perioperative risk or whether the time interval from pneumonia to surgery affects this relationship. Furthermore while diabetes mellitus and anaemia are known to be important perioperative risk factors, the relationship between haemoglobin concentration or HbA1c levels and perioperative outcomes is unclear. The aim of this epidemiological study is to explore these associations with perioperative risk in the United Kingdom Clinical Practice Research Datalink (with linkage to Hospital Episode Statistics data and Office of National Statistics mortality data).

The research aims are:

1. To investigate the association between three recent acute medical events (stroke, pneumonia and MI) and adverse perioperative outcomes following non-cardiac and cardiac surgery.
2. To investigate the association between time-elapsed between acute medical events (stroke, pneumonia and MI) and adverse perioperative outcomes following non-cardiac and cardiac surgery.
3. To investigate numerical risk thresholds for haemoglobin and HbA1c that could predict adverse perioperative outcomes following non-cardiac and cardiac surgery.