#772 Causes of non-elective hospitalisations among adult patients with chronic kidney disease in England: Clinical Practice Research Datalink 2010-2019
Authors: Cockwell Paul , Farmer Ruth , Popoola Remi , Muttram Louise , Shay Christina 
Published: May 2024

Abstract

Background and Aims
Patients with chronic kidney disease (CKD) are at higher risk of non-elective hospitalisation compared to the general population, which is associated with an increased risk of death and accounts for disproportionate resource utilisation. There are limited population-level estimates of the causes of non-elective hospitalisation for patients with CKD in England. Therefore, a population-based study was implemented to start to address this shortfall.

Method
This non-interventional, observational study utilised data from primary care electronic health records from the Clinical Practice Research Datalink (CPRD) AURUM and Hospital Episode Statistics (HES) admitted patient care (APC). Patients aged ≥18 years registered in CPRD with eligible linkage to HES between January 1, 2010-December 31, 2019 with at least two eGFR measurements during that period were identified. CKD was defined by an eGFR &lt;60 ml/min/1.73 m2 and/or presence of a uACR measurement ≥3 mg/mmol, both confirmed by a second measurement 90-365 days later. Start of follow-up (index) was set to the earliest date during the study period where CKD was confirmed. Non-elective admissions were defined as hospitalisations not planned in advance. Follow-up for hospitalisations ended at the earliest of death, administrative censoring, or December 31, 2019. Patients with end stage kidney disease at index were excluded. Causes of hospitalisation during follow-up were based on three character-level ICD codes in the primary position. Where the same ICD-10 code was coded more than once within a hospitalisation, it was only counted once.

Results
From a total population of 6.1 million adult patients meeting study inclusion criteria, 743.945 adults with CKD were identified (12.2%) with a median follow-up of 3.62 years. The mean age (SD) was 76.1 (11.5) years, 55.2% were female, and 89.8% were White. The majority (60.9%) of patients had stage 3a CKD (eGFR 45-59 ml/min/1.732 m2) and 34.3% and 17.1% had a history of type 2 diabetes and heart failure at time of CKD confirmation, respectively. There were 1.45 million non-elective hospitalisations observed, with 449.128 (60%) of patients experiencing ≥1 non-elective hospitalisation during follow-up. The most frequent ICD-10 chapter indicated as primary cause of all non-elective hospitalisation was diseases of the circulatory system (19.4%), including heart failure (4.9%), ischaemic heart disease (myocardial infarction and angina) (3.5%), stroke (2.2%) and atrial fibrillation/flutter (1.9%). Infection was also a frequent cause of non-elective hospitalisation, including pneumonia of unspecified organism (7.8%), unspecified acute lower respiratory tract (2.5%), and other sepsis (2.7%). Frequent hospitalisation also occurred in patients with CKD due to fractures (3.5%) and injuries to the head (1.7%).

Conclusion
Non-elective hospitalisations are frequent among patients with CKD. Diseases of the circulatory and respiratory systems are overall most common causes, with pneumonia, ischaemic heart disease, and heart failure the most frequent modifiable reasons for admission. Ensuring that current shortfalls in primary and secondary prevention for patients with CKD through optimization of strategies such as vaccination and evidence based cardiovascular disease management will reduce rates of non-elective hospitalisation and other clinical outcomes and ensure best use of health care resources for patients with CKD.