Background: Harmful alcohol intake is the commonest cause of liver disease worldwide and is associated with cancers (including stomach and bowel cancer) and other conditions such as hernia and gallstones. Usually, surgery for these conditions carries a low risk of death but in patients with alcoholic liver disease, the risk may be greater. However, there is very little scientific evidence on outcomes after surgery in patients with alcoholic liver disease.
Design: We will use data from two large electronic health records from England, the Clinical Practice Research Datalink (CPRD), and Hospital Episode Statistics (HES) to form a study population of patients having abdominal surgery along with data from the Office of National Statistics. We will then group patients into those with liver disease and those without liver disease. The liver disease group will be further subdivided into those caused by alcohol and those not caused by alcohol. Patients will be followed up from the time they have surgery up until one year or death whichever happens first. We will compare the health outcomes in patients with alcoholic liver disease to the general population without liver disease having the same surgery.
Outcomes and patient benefit: The three important outcomes we will assess are the risk of liver disease worsening after surgery, the risk of venous thrombosis (which are clots that form in veins of patients particularly after surgery) and importantly the risk of death after surgery. Knowing these important outcomes will allow patients and doctors to make informed decisions about the care they are willing to receive.
Background: Alcohol is the commonest cause of chronic liver disease worldwide and is reported to increase the risk of some benign and malignant gastrointestinal diseases for which surgery may be indicated. Operative mortality for gastrointestinal conditions is reportedly low in the general population. However, surgery in patients with alcoholic liver disease can precipitate hepatic decompensation and may be associated with a higher risk of mortality.
The main objective of this study is to determine the postoperative risk of hepatic decompensation, venous thromboembolism and mortality after extrahepatic gastrointestinal surgery in patients with alcoholic liver disease when compared with patients with no liver disease undergoing the same surgical procedures.
Design: HES data will be used to form a study population of all patients undergoing gastrointestinal surgery and linked to their primary care data (CPRD). Patients will be grouped into those with liver disease as the study cohort by the presence of relevant codes for liver disease. Those without liver disease will form the control group. Of the liver disease patients, those with an alcohol aetiology will be identified by a separate algorithm that includes codes for harmful use of alcohol, or via codes that specifically mention an alcohol related cause. Those with liver disease will be subsequently classified based on severity as cirrhotic or not cirrhotic and compensated or decompensated cirrhosis.
For each included surgical procedure, we will report crude rates of decompensation, rates of postoperative venous thromboembolism and rates of mortality. A Cox proportional hazards model will be fitted to the alcoholic liver disease cohort predicting risk of decompensation, venous thromboembolism and mortality following operation. From this, we will derive cumulative incidence functions. In the case of decompensation and venous thromboembolism we will account for the competing risk of death. These absolute risks will be reported overall and stratified where there is adequate power by the strata liver disease severity.
Post-operative hepatic decompensation
Post-operative rates of venous thromboembolism
Post-operative Mortality at 30-days and Mortality at 1-year
David Humes - Chief Investigator - University of Nottingham
Alfred (Alfie) Adiamah - Corresponding Applicant - University of Nottingham
Colin Crooks - Collaborator - University of Nottingham
Joe West - Collaborator - University of Nottingham
Lu Ban - Collaborator - University of Nottingham
HES Admitted Patient Care;ONS Death Registration Data;Patient Level Index of Multiple Deprivation