Epidemiology in anaesthesia. III: Mortality risk in patients with coexisting physical disease.

The Cardiff Anaesthetic Record System has been used to examine the hospital mortality rates and relative risks for patients having anaesthesia who have certain preoperative conditions coexisting with their disease requiring surgery. Each preoperative condition was associated with a higher mortality rate than occurred in patients with no preoperative condition (for example ischaemic heart disease 7%, diabetes 5.7%, no preoperative condition 0.5%). Mortality was greater for emergency than for elective operations. In contrast to an increasing mortality by age, the relative mortality risk decreased, suggesting that in older age groups coexisting disease may be less important than other risk factors in determining mortality.