Impact of clinical urgency, physician supply and procedural capacity on regional variations in wait times for coronary angiography

Harindra C Wijeysundera,David A Alter,Madhu K Natarajan,Alice Chong,Therese A Stukel

doi:10.1186/1472-6963-10-5

Abstract

BackgroundDespite universal health care, there continues to be regional access disparities to coronary angiography in Canada. Our objective was to evaluate the extent to which demand-side factors such as clinical urgency/need, and supply-side factors, as reflected by differences in physician and procedural supply account for these inequalities.MethodsOur cohort consisted of 74,254 consecutive patients referred for coronary angiography in Ontario, Canada between April 1st 2005 and March 31st 2006, divided into three urgency strata based on a clinical urgency scale. Cox-proportional hazard models were developed, adjusting for age, gender, socioeconomic status (SES), region, and urgency score, with greater hazard ratios (HR) indicating shorter wait times. To evaluate mediators of any residual wait-time differences, we examined the influence of the regional supply of cath lab facilities, invasive cardiologists and general practitioners (GP).ResultsWe found that the urgency score was a significant predictor of wait time in all three strata (urgent patients: HR 1.61 for each unit increase in patient urgency (95% Confidence interval (CI) 1.55-1.67); semi-urgent patients: HR 1.55 (95% CI 1.44-1.68); elective patients: HR 1.13 (95% CI 1.08-1.18)). After accounting for clinical need/urgency, regional wait time differences persisted; these were most consistently associated with variation in cath lab supply. The impact of invasive cardiologist supply was restricted to urgent patients while that of GP supply was confined to semi-urgent and elective patients.ConclusionWe found that there remained significant regional disparities in access to coronary angiography after accounting for clinical need. These disparities are partially explained by variations in supply of both procedural capacity and physician services, most notably in elective and semi-urgent patients.

Highlights

Despite universal health care, there continues to be regional access disparities to coronary angiography in Canada
The urgency score was a statistically significant predictor of time to angiography (HR for urgent patients 1.61, 95% CI 1.551.67; hazard ratios (HR) for semi-urgent patients 1.55, 95% CI 1.44-1.68; HR for elective patients 1.13, 95% CI 1.08-1.18)
The impact of invasive cardiologist supply was restricted to urgent patients, with a wait time reduction of 17% with an increased allocation of one invasive cardiologist per 100,000 persons (HR 1.20; 95% CI 1.141.26) (Table 4)

Summary

Introduction

There continues to be regional access disparities to coronary angiography in Canada. The Cardiac Care Network (CCN) is a centralized, province-wide registry of patients waiting for coronary angiography, angioplasty and bypass surgery in the province of Ontario[11]. In support of this registry, a 1993 Canadian physician expert panel developed an explicit urgency rating scale, based on five clinical parameters, to be used for coronary angiography triage. Recommended maximum waiting times (RMWT) were allocated based on urgency scores[12] This urgency score has been validated as an accurate measure of clinical need given its correlation with implicit physician judgment and the risk of adverse events in patients on the waiting list[13].

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Discussion

Conclusion