Setting targets for CABG surgery in the north western region

Area of Science:

• Cardiovascular Surgery
• Health Services Research
• Public Health Policy

Background:

• A national target of 300 coronary artery bypass graft (CABG) operations per million population was set by the Department of Health in 1987.
• Regional Health Authorities were mandated to achieve this target by 1993-1994, but the 1990-1991 rate was 239 per million.
• The North Western Region's planned devolution of cardiac surgery purchasing to districts highlighted the absence of a method to estimate operation rates based on need.

Purpose of the Study:

• To devise a method for calculating guideline targets for coronary artery bypass graft (CABG) operations at the district level.
• To ensure operation rates reflect the actual need for cardiac surgery within district populations.
• To address the wide variations in CABG rates observed across the North Western Region.

Main Methods:

• Utilized a linear regression model assuming the ischaemic heart disease standardized mortality ratio (IHD SMR) as a proxy for CABG need.
• Employed existing district IHD SMRs and IHD hospitalization rates to derive guideline targets.
• Explored alternative Poisson regression models and weighting formulae for target derivation.

Main Results:

• Derived operation targets using the linear regression model were lower than current rates in three provider districts and their neighbors.
• Targets exceeded existing operation numbers in most other districts.
• Alternative analyses yielded broadly similar results, confirming the derived targets.

Conclusions:

• Significant variations in CABG operation rates were identified within the North Western Region.
• Access to CABG surgery appeared influenced by geographical proximity to provider districts.
• The presented method provides a means to derive district-specific CABG targets that are need-based.