Identification of clinically relevant cohorts of people with heart failure from electronic health data in Aotearoa: potential, pitfalls and a plan.

Heart failure (HF) is associated with high morbidity and mortality and contributes to substantial burden of disease, significant inequities and high healthcare cost globally as well as in Aotearoa. Management of chronic HF is driven by HF phenotype, defined by left ventricular ejection fraction (EF), as only those with reduced ejection fraction (HFrEF) have been shown to experience reduced mortality and morbidity with long-term pharmacotherapy. To ensure appropriate and equitable implementation of HF management we need to be able to identify clinically relevant cohorts of patients with HF, in particular, those with HFrEF. The ideal HF registry would incorporate and link HF diagnoses and phenotype from primary and secondary care with echocardiography and pharmacotherapy data. In this article we consider several options for identifying such cohorts from electronic health data in Aotearoa, as well as the potential and pitfalls of these options. Given the urgent need to identify people with HF according to EF phenotype, the options for identifying them from electronic health data, and the opportunities presented by health system reform, including a focus on digital solutions, we recommend the following four actions, with oversight from a national HF working group: 1) Establish a HF registry based on random and representative sampling of HF admissions; 2) investigate obtaining HF diagnosis and EF-phenotype from primary care-coded data; 3) amalgamate national echocardiography data; and 4) investigate options to enable the systematic collection of HF diagnosis and EF-phenotype from outpatient attendances. Future work will need to consider reliability and concordance of data across sources. The case for urgent action in Aotearoa is compounded by the stark inequities in the burden of HF, the likely contribution of health service factors to these inequities and the legislative requirement under the Pae Ora (Healthy Futures) Act 2022 that "the health sector should be equitable, which includes ensuring Māori and other population groups - (i) have access to services in proportion to their health needs; and (ii) receive equitable levels of service; and (iii) achieve equitable health outcomes".