Inequities in heart-kidney care: Why are people with kidney disease at increased risk of death and disability after a heart attack?

Background Coronary artery disease results in significant morbidity and mortality in people with chronic kidney disease (CKD).[1,2] The incidence of heart attack ('acute myocardial infarction' (AMI)) is four times greater in people with advanced CKD than in the general population[3] and mortality is increased by up to 15-fold.[4, 5] People with CKD have frequently been excluded from randomised controlled trials in cardiovascular medicine[6] so evidence for the optimal treatment of AMI in this population is lacking.

Evidence from observational studies and subgroup analyses of randomised controlled trials supports the use of standard secondary preventative medications for AMI in people with CKD.[9-9] This is reflected in current guidelines.[10,11] Prescribing practice has not been studied in England, however research from the US and Europe demonstrates widespread underuse of such medications.[4, 12] The risk benefit balance for procedures to improve blood flow to the heart ('revascularisation') following AMI for people with CKD is less clearly understood and guidelines recommend individualised decision-making.[10, 11] In England and elsewhere, people with CKD are much less likely to undergo invasive imaging of their heart ('angiography') as well as to receive revascularisation.[13, 14] Reasons for these differences have not been investigated.

Variation in care may be appropriate if it reflects the specific needs of a population, however increasingly evidence suggests that differences in AMI care for people with CKD may be an inappropriate restriction of access to effective treatment ('healthcare inequity').[14, 15] Aim To investigate whether people with CKD experience equitable AMI management in England, and the barriers and facilitators to the provision of optimal care.

Objectives 1. To identify the evidence base for equity of AMI care for people with CKD. 2a. To describe AMI care for people with CKD in England . 2b. To compare sensitivity and specificity of CKD algorithms in UK datasets. 2c. To investigate equity of AMI care for people with CKD in England. 3. To identify barriers and facilitators to the provision of optimal AMI care for people with CKD.

Methods Phase 1 A systematic review will be conducted to identify the evidence base for equity of AMI care for people with CKD (objective 1).

Phase 2 Linked data from the Clinical Practice Research Datalink and Hospital Episode Statistics will be used to describe AMI care for people with and without CKD in England (objective 2a) and determine specificity and sensitivity of CKD algorithms in these datasets (objective 2b).

Equity will be assessed by comparing cardiovascular medication prescription against evidence-based guidelines and analysing outcomes of those who do and do not undergo angiography (objective 2c).

Phase 3 Semi-structured interviews with patients and clinical staff will enable identification of facilitators and barriers to providing optimal AMI care for patients with CKD in England (objective 3). Timelines for delivery Three years.

Anticipated impact and dissemination This research will provide the evidence base for equity of AMI care for people with CKD in the UK, forming the foundations for post-doctorate work in which I intend to develop intervention(s) to optimise AMI care for this population.