Using ICD-10 Diagnostic Codes to Identify ‘Missing’ Paediatric Patients During Nationwide COVID-19 Lockdown in Oxfordshire, UK

Abstract Objective: To identify diagnoses which were ‘missing’ amongst paediatric inpatients during the UK’s first national lockdown, compared with the same period over the past five years.Study design: A retrospective observational cohort study of all children (0-15 years) attending for urgent care across Oxfordshire, during the first UK lockdown in 2020, compared to matched dates in 2015-2019. This covers two paediatric hospitals providing secondary care, one with tertiary services. Main outcomes: Changes in numbers of patients attending and inpatient diagnoses (using ICD-10 classification) during the first 2020 lockdown, compared with the previous five years.Results: Total ED attendances (n=4030) and hospital admissions (n=1416) during the first UK lockdown were reduced by 56.8% and 59.4%, respectively, compared to attendances/admissions in 2015-2019 (5-year mean n=7446.8 and n=2491.6, respectively). Proportions of patients admitted from ED and length of stay were similar in lockdown to 2015-2019. Significantly greater numbers of neoplasms were diagnosed during lockdown than the same period in 2015-2019 (p= 0.0123). 80% of diagnoses ‘missing’ during lockdown were categorised as infectious diseases or their sequelae, whilst 20% were non-specific pains/aches/malaise and accidental injury/poisonings. Conclusions: Using standardised ICD-10 codes as a measure of diagnostic activity between years; ‘missing’ diagnoses can be identified. Our findings may suggest parents are supervising infectious illness at home or had anxieties about hospital attendance, with self-limited low-morbidity disease. Prospective studies should establish if parents/carers are adequately supported in caring for their children at home, and that access and referral pathways are appropriate where children have concerning clinical features.