Relative Survival – What Can Cardiovascular Disease Learn from Cancer?

Aims: To illustrate the application of relative survival to observational studies in coronary heart disease and potential advantages compared to all-cause survival methods. Survival after myocardial infarction is generally assessed using all-cause or cause-specific methods. Neither method is able to assess the impact of the disease or condition of interest in comparison to expected survival in a similar population. Relative survival, the ratio of the observed and the expected survival rates, is applied routinely in cancer studies and may improve on current methods for assessment of survival in coronary heart disease. Methods and results: Using a cohort of subjects after a first recorded acute myocardial infarction, we discuss the application of relative survival in coronary heart disease and illustrate a number of the key issues. We compare the findings from relative survival with those obtained using Cox proportional and non-proportional hazards models in standard all-cause survival. Estimated survival rates are higher using relative survival models compared to all-cause methods. Conclusion: Estimates obtained from all-cause mortality fail to disentangle mortality associated with the condition of interest from that due to all other causes. Relative survival gives an estimate of survival due to the disease of interest without the need for cause of death information.