Patients undergoing emergency surgery in lower income countries have a three times greater chance of dying than in higher income countries, according to a study released Wednesday by the University of Edinburgh.

Researchers from the Universities of Edinburgh, Birmingham and Sheffield monitored post-surgery death rates and mapped them against the Human Development Index (HDI) of various countries. Some 10,745 patients were monitored up to 30 days after undergoing emergency abdominal surgery, at hospitals in 58 participating countries.

The study showed that death rates were three times higher in low income countries than in high income countries, even after adjustment for factors such as fitness for surgery, diabetes history and smoking status.

It is believed that less than a third of the world's population have access to safe, timely and affordable surgery, said the researchers.

Only six percent of the 300 million surgical procedures performed each year take place in low or middle income countries, despite a third of the world's population living there, according to the study.

"Improving surgical access and safety can only be achieved if we really understand what influences surgical outcomes on a global scale," said Ewen Harrison, a clinical senior lecturer at the University of Edinburgh.

The findings have been published in the British Journal of Surgery.