What is the relationship between chronic kidney disease, multiple long-term conditions and the risk of hospitalisation?

Problem

Chronic Kidney Disease typically co-exists with multiple long-term conditions. The associations between Chronic Kidney Disease, multiple long-term conditions and hospitalisation rates are not known. We aimed to examine hospitalisation rates in people with multiple long-term conditions with and without Chronic Kidney Disease. We also aimed to identify high risk patterns of long-term conditions amongst people with Chronic Kidney Disease.

Approach

Two cohorts were studied in parallel: UK Biobank (2006-2019) and Secure Anonymised Information Linkage Databank (SAIL: 2011-2018). UK Biobank is a prospective research study. SAIL is a Welsh routine care database. Nine categories of participants were used: zero long-term conditions; one, two, three and four or more long-term conditions excluding Chronic Kidney Disease; and one, two, three and four or more long-term conditions including Chronic Kidney Disease. Hospitalisation events were obtained from linked hospital records.

Findings

Among 469,344 UK Biobank participants, 10,767 (2.3%) had Chronic Kidney Disease. Among 2,611,238 SAIL participants, 173,388 (6.6%) had Chronic Kidney Disease. Compared to those with zero long-term conditions, participants with four or more long-term conditions (excluding Chronic Kidney Disease) had high event rates (Rate Ratios 5.35 (95% confidence interval 5.20-5.51)/4.88 (4.64-5.14)) with higher rates if Chronic Kidney Disease was one of the long-term conditions (Rate Ratios 8.99 (8.47-9.54)/21.20 (20.87-21.50)). The type of long-term condition was important: those with Chronic Kidney Disease plus multiple cardiometabolic conditions, Chronic Kidney Disease plus complex long-term conditions (three or more long-term conditions affecting three or more body systems) and Chronic Kidney Disease plus physical and mental long-term conditions were at heightened risk of hospitalisation.

Consequences

People with multiple long-term conditions have high rates of hospitalisation. Importantly, the rates are two to four times higher when Chronic Kidney Disease is one of the long-term conditions. Further research is needed to explore the mechanisms behind this and to inform strategies to prevent hospitalisation in high-risk groups.