Acute kidney injury (AKI) is a common and serious condition characterised by a sudden worsening in kidney function. It usually occurs as a complication of another serious illness. It affects around half a million people in England each year, with older frail people living with multiple long-term conditions being especially vulnerable. People discharged from hospital after AKI have high rates of unplanned readmissions and are at high risk of developing other serious illnesses such as chronic kidney or heart diseases. It is unclear how factors associated with the patients, clinicians and health care systems contribute to these outcomes. There has also been limited progress over the years on improving outcomes and the patient experience of post-discharge AKI care.
We want to understand and improve the quality of post-discharge care following AKI. For patients discharged from hospital with a diagnosis of AKI, we will first investigate the quality of their post-discharge care delivered by general practices. Quality will be measured according to a set of standards. For example, whether the patients have received timely clinical consultations, appropriate medicine prescriptions, and kidney function tests after discharge. Secondly, we will investigate what patient and general practice characteristics contribute to the differences in the delivery of their care.
Because AKI affects so many people each year, improved post-discharge care after AKI would lead to sizable overall benefits across the UK. Our findings will be used to help develop practical recommendations and to inform national policy for the improvement of post-discharge AKI care.
In this cohort study, we will investigate variations in the implementation of recommended person-centred post-discharge acute kidney injury (AKI) care and what factors are associated with these variations.
Using HES admission data, we will delineate a cohort of patients aged 18 or over who have been discharged from hospital with a hospital diagnosis of AKI between 2017 and mid-2022. From linked CPRD Aurum data, we will access the proportion of these patients meeting previously developed indicators representing good standard of post-discharge AKI care delivered by general practices. These cover areas of, for example, clinical coding of AKI in the patient’s primary care record, timely clinical reviews, optimising medicines management, and essential testing of blood and kidney functions. To assess processes of care to inform care pathway analysis, we will also investigate GP practice appointments, outpatient attendance, A&E attendance, and repeat hospital admission within 90 days following discharge.
We will calculate the proportion of patients meeting each indicator (with 95% confidence intervals). Variation in proportions between practices will be quantified for each indicator using a mixed effects three-level logistic regression model with patients nested within practices and within region. We will describe adherence according to patient characteristics: age group, sex, ethnicity, index of multiple deprivation (IMD) quintile, and evidence of frailty and multiple long-term conditions such as diabetes and heart failure, as well as according to practice characteristics: region, IMD quintile, and urban-rural classification.
Our findings will be used to target improvements in the quality of post-discharge care following AKI. We anticipate that our research will lead to:
• More patient-centred care at and beyond the point of discharge following AKI;
• Wider implementation of standards for best practice; and
• Improved short and long-term patient outcomes, e.g. unplanned re-admissions associated with AKI, chronic kidney disease progression, and cardiovascular health.
The primary outcomes will be the proportion (with 95% confidence intervals) of patients meeting each of the following post-AKI care indicators, developed through our leadership of national standards [1-4] and our NIHR CLAHRC-funded development of operational definitions [5,6].
For all people with AKI-related hospitalisation following discharge:
• Clinical coding of AKI in the primary care electronic health record within 30 days.
• Consultation with healthcare professional within 30 and 90 days, and mode of consultation and type of healthcare professional.
• Testing of blood pressure and essential blood and urine kidney tests to monitor for new onset chronic kidney disease (CKD), CKD progression or kidney recovery, within 120 days (i.e. allowing up to 30 days beyond the ~90 day time point advocated in guidelines) and 455 days (i.e. allowing up to 90 days beyond 12 months) post-discharge.
• No prescriptions for Non-Steroidal Anti-Inflammatory Drugs (NSAIDs; known to be harmful to kidneys) within 90 days.
• Evidence of provision of written information about AKI within 90 days, in accordance with NICE guidelines on giving information about long-term treatment options, monitoring, self-management and support to people who have had AKI [4].
For subgroups of patients, we will consider:
• Early consultation with healthcare professional within 2 weeks for those with heart failure, and mode of consultation and type of healthcare professional.
• Prescribing of angiotensin-converting-enzyme (ACE)-inhibitor or angiotensin receptor blockers (ARB) medication within 90 days where clinically indicated for heart failure [7], previous myocardial infarction [8], diabetes or hypertension with poorer kidney function, and CKD with proteinuria [9].
• Prescription of appropriate cardiovascular risk prevention medication (antiplatelet and lipid lowering) in accordance with NICE clinical guideline [10].
• Coding of CKD among those without prior CKD but have developed de novo CKD due to non-recovery based on blood and urine tests at ~90 days (allowing up to 120 days), as stipulated in Kidney Disease: Improving Global Outcomes (KDIGO) guidelines. De novo CKD is defined as eGFR <60 ml/min/1.73m² or new onset proteinuria assessed using ACR/ PCR / urine dipstick. For those with CKD of any stage, accurately updated coding of CKD and CKD stage based on blood test at ~365 days (allowing up to 455 days for repeat testing) [11].
Secondary outcomes are the proportion (with 95% CI) of all patients with AKI-related hospitalisation with records of:
• Outpatient attendance (any attendance, and attendance to cardiology and nephology/renal clinics in particular)
• A&E attendance (for any cause)
• Unscheduled repeat hospital admission (for any cause)
• Death (from any cause)
within 90 days following discharge.
Darren Ashcroft - Chief Investigator - University of Manchester
Pearl Mok - Corresponding Applicant - University of Manchester
Andrew Lewington - Collaborator - University of Leeds
Evangelos Kontopantelis - Collaborator - University of Manchester
Nicholas Selby - Collaborator - University of Nottingham
paul roderick - Collaborator - University of Southampton
Robbie Foy - Collaborator - University of Leeds
Simon Fraser - Collaborator - University of Southampton
Simon Sawhney - Collaborator - University of Aberdeen
Tom Blakeman - Collaborator - University of Manchester
HES Accident and Emergency;HES Admitted Patient Care;HES Outpatient;ONS Death Registration Data;Patient Level Index of Multiple Deprivation;Practice Level Index of Multiple Deprivation;CPRD Aurum Ethnicity Record;Practice Level Rural-Urban Classification