Chart of the week: Emergency admissions for asthma and COPD during Covid-19

Each week we present analysis of data in chart form to illustrate some key issues and invite discussion. How have people with severe forms of common lung diseases like asthma and COPD been affected by the pandemic? Jessica Morris takes a look at emergency admissions for these illnesses over the past year and finds that counterintuitively, emergency admissions have decreased - but the reasons for this are tricky to unpick.

Chart of the week

Published: 07/07/2021

Early in the pandemic, asthma and chronic obstructive pulmonary disease (COPD) – the two most common lung diseases in the UK – were identified as risk factors for serious illness from Covid-19. Patients with severe asthma or COPD were defined as clinically extremely vulnerable and added to the Shielded Patient List, even though a more recent study found their risk of severe Covid to be more modest than previously thought.

Counterintuitively, emergency admissions for these chronic lung conditions fell to a greater extent than for other conditions at the start of the coronavirus pandemic. In April last year, emergency admissions for both asthma and COPD were around 65% lower than in April 2018, compared to a drop of 39% for all diagnoses combined.

After increasing during last summer, emergency admissions for asthma and COPD plummeted again during the second Covid wave in the autumn, while the overall admission rate only dipped slightly. By March this year, overall emergency admissions were higher than in March 2019, but it wasn’t the same story for COPD admissions, which remained a quarter lower than they were previously, while asthma admissions were over a third lower.

Unpicking the reasons for these falls in admissions is complicated. One explanation is that stay-at-home messages and fear of the virus may have deterred patients with asthma and COPD exacerbations from accessing health care. Lockdown measures also led to a reduction in air pollution and transmission of other respiratory viruses including influenza, which are likely to have had a positive effect on patients with asthma and COPD. And changes in clinical coding may have contributed: Covid-19 patients admitted to hospital with asthma or COPD symptoms may not have these recorded as their main diagnosis.

Tracking trends in emergency admissions for asthma and COPD will be important this winter, especially with reports of flu possibly being a bigger problem than Covid-19 by the end of the year. This may result in an influx of admissions for patients with worsening asthma and COPD symptoms, which could put significant pressure on emergency departments.


Data notes

This chart uses data from Hospital Episode Statistics (HES) Admitted Patient Care dataset and NHS England. The HES indicators for asthma and COPD emergency admissions were calculated according to NHS Digital’s Ambulatory Care Sensitive Conditions specifications.

This included Finished Consultant Episodes where admission method was ‘emergency’.

International Classification of Diseases (ICD) 10 codes were used to identify each condition.


  • J45 (Asthma) and J46 (Status asthmaticus)
  • Principal diagnosis only

Chronic obstructive pulmonary disease

  • J41 (Simple and mucopurulent chronic bronchitis), J42 (Unspecified chronic bronchitis), J43 (emphysema), J44 (Other chronic obstructive pulmonary disease), J47 (Bronchiectasis) – Principal diagnosis only
  • J20 (Acute bronchitis) – only if there is a secondary diagnosis of J41, J42, J43, J44, J47