Socioeconomic inequality in waiting times for heart bypass and angioplasty: does patient choice explain the gradient?

Equity of access is a key policy objective in publicly-funded healthcare systems. One important marker of equity is socioeconomic inequality in hospital waiting times, which have been shown to exist even within universal publicly funded health systems like the UK NHS. However, it is not known how far such inequalities are due to patient choice – for example, affluent patients might opt for lower-wait procedures, or choose to travel further to hospitals with shorter waits. 

We examine this question by focusing on waiting times for heart bypass and angioplasty. These two procedures can substantially improve the quality of life of people with clogged arteries, are performed more than 30,000 times a year in England, and have different waiting times (bypass patients wait longer). In a bypass operation, doctors move healthy blood vessels from other parts of the body to detour around clogged arteries supplying blood to the heart. Whereas angioplasty treats the problem via a tube pushed through a blood vessel. 

Using data on patients undergoing non-emergency heart bypass and angioplasty procedures in the English National Health Service during the 2000s, we find evidence of significant differences in waiting times within public hospitals between patients with different socioeconomic status. We employ selection models to test whether such differences are explained by patients exercising choice over hospital or type of treatment (i.e. bypass or angioplasty). Selection bias due to either kind of choice has a significant but limited effect on the gradient. After allowing for choice, bypass patients from the most deprived population quintile group of neighbourhoods in England waited 35% longer than those in the least deprived group in 2002, falling to 10% by 2010. And the gap for angioplasty was even wider: a 50% differential in 2002, falling to 15% by 2010. 

We have found that substantial socioeconomic inequalities in the English NHS can occur within the same hospital, for patients waiting for effective treatment for a condition that can seriously impact on quality of life while the patient is waiting. Our contribution in this paper has been to show that these inequalities are not primarily caused by differences in patient choice of hospital or procedure. We are still not sure why these inequalities do occur, however. One mechanism may be “elbowing behaviour” by advantaged patients who are better endowed with information and lobbying skills, along with defensive medicine by hospital staff worried about the risk of complaints and ultimately legal action. A second mechanism may be “unconscious bias”, which can occur if doctors are better able to understand and interpret the health symptoms of patients who are closer to them in terms of socioeconomic status. Further research is needed to explore these and other potential causal mechanisms and thereby identify potential policy remedies.

Full Report: CHE Research Paper 112 (PDF , 2,904kb)

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