Opportunities and challenges in using English national Hospital Episode Statistics to study infectious disease epidemiology

Abstract

The aim of this PhD by published work is to demonstrate the opportunities and challenges of using
Hospital Episode Statistics – Admitted Patient Care (HES-APC), which is the national database of routinelycollected hospital admission records in the English National Health Service (NHS), for the investigation of
infection-related disease, to provide insights into disease patterns, risk factors, outcomes, and healthcare
utilisation. Specifically, this thesis incorporates ten publications, which between them cover the following
three themes of epidemiological research:
(i) Cross-sectional studies of population-based trends in admission rates for specified infectious
diseases over time. Such studies can help to inform the impact of health policy changes,
treatment measures and patient behaviours, such as changes to the vaccine schedule or changes
in vaccine uptake, implementation of screening, improved diagnostic testing, and national
lockdowns. However, the data themselves can be subject to temporal changes, for example in
clinical coding practice or admission thresholds, necessitating cross-reference with other sources.
Two of these studies also make use of historical national and regional predecessor datasets to HES,
to provide greater historical context, the merits and challenges around which are explored.
(ii) Cohort and case-control studies to explore associations between perinatal factors and infectious
diseases in children. HES-APC can represent national birth cohorts with up to 25 years of followup, enabling population-based studies of perinatal risk factors for infectious disease in childhood
or early adulthood, and/or the study of childhood infection as a risk factor for later disease.
However, the maternity HES data suffer problems of data completeness and quality, which are
discussed.
(iii) Longitudinal cohort studies to investigate hypothesised associations between infectious diseases
and chronic non-communicable diseases. Such studies can help to inform potential treatment or
vaccination efforts through new insights into non-communicable disease aetiology, which may be
pursued further in clinical trials or using more detailed observational data.
Each of the included works was guided by the principle of putting quantitative findings into their clinical
context in order to inform hypothesis-driven narratives for translational impact.

Date of Award	18 Mar 2025
Original language	English
Awarding Institution	University of Bristol
Supervisor	Rachel E Denholm (Supervisor) & Jonathan A C Sterne (Supervisor)