The direct and indirect effects of Covid-19 on long-term conditions: A retrospective cohort study using primary and secondary care electronic health records

Date of ISAC Approval: 
22/02/2021
Lay Summary: 
Both the short and longer-term health effects of COVID-19 are unknown. While the coronavirus primarily causes a respiratory illness, it also has effects on other body parts such the heart, kidneys and blood cells and can therefore present with a wide range of symptoms. The effects of COVID-19 may last significantly longer than the initial infection. People who have had COVID-19 may have an increased risk of developing long-term health conditions such as other respiratory illnesses, heart and circulatory diseases, and blood disorders. The impact of the COVID-19 pandemic on the care and management of people with long-term health conditions is also largely unknown. It is likely to be considerable given there is reduced access to healthcare including fewer face-to-face consultations and monitoring of health conditions. The health of people with long-term conditions may have been adversely affected in both the short and longer-term. There may also be unintended effects of having more telephone consultations instead of face-to-face appointments with potential impacts on the rates of prescribing of medications such antidepressants, antibiotics and opioids. The aim of this research is to assess whether having COVID-19 influences the risk of being diagnosed with certain long-term health conditions. We will also assess the impact of the COVID-19 pandemic on the health of people with long-term health conditions. This may help us to understand the impact of the pandemic on people with long-term conditions, and to help lessen the impact of these effects in ongoing and future surges of infection within the community.
Technical Summary: 
This study comprises three interrelated studies which, overall, aim to assess the direct effects of a SARS-CoV-2 infection, and the indirect effects of the COVID-19 pandemic on the diagnosis and management of chronic conditions. Firstly, we will use a series of retrospective cohort studies to analyse the short-term effects of SARS-CoV-2 infection on risk of developing common chronic diseases including autoimmune diseases, chronic kidney disease (CKD), cardiovascular disease (CVD), diabetes, gastrointestinal and liver diseases, haematological diseases (including venous thromboembolism), mental health diseases, neurological diseases, and respiratory diseases. These cohort studies will use descriptive statistics and Cox proportional hazard models to examine the association between SARS-CoV-2 infection and the incidence of each of these chronic diseases, adjusted for sociodemographic and clinical characteristics characteristics. Secondly, for those already diagnosed with these long-term conditions, we will use controlled interrupted time series analysis to assess any change in disease-specific measurements of clinical management, and rates of prescriptions and referrals during 2020 compared with the three years preceding the COVID-19 pandemic, with particular reference to March 23rd 2020, when the first lockdown was announced. Finally, using Cox proportional hazard models we will assess whether the severity of the long-term conditions at baseline predicts the hazard of infection with SARS-CoV-2, and subsequent hospitalisation and mortality. These models will be stratified by sex and we will adjust for sociodemographic characteristics and other risk factors for SARS-CoV-2 infection.
Health Outcomes to be Measured: 
Study 1: Outcomes for the Retrospective Cohort Analysis include: Incidence of predefined long-term health conditions (autoimmune diseases, chronic kidney disease (CKD), cardiovascular disease (CVD), diabetes, gastrointestinal and liver diseases, haematological diseases, mental health diseases, neurological diseases, and respiratory diseases); and hospitalisation related to each specific long-term health condition. Study 2: Outcomes for Interrupted Time Series include Incidence of SARS-CoV-2 infection; hospitalisation for SARS-CoV-2 infection; disease-specific measures of clinical management of long-term health conditions including biochemical biomarkers of disease and blood pressure, rate of medication prescription, occurrence of disease-specific clinical reviews, rate of referral to specialist care or service; cause-specific mortality; and all-cause mortality. Study 3: Outcomes of Retrospective cohort analysis include: SARS-CoV-2 infection; hospitalisation for SARS-CoV-2 infection; mortality associated with SARS-CoV-2 infection.
Collaborators: 

Krishnarajah Nirantharakumar - Chief Investigator - University of Birmingham
Jennifer Cooper - Corresponding Applicant - University of Birmingham
Francesca Crowe - Collaborator - University of Birmingham
Anuradhaa Subramanian - Collaborator - University of Birmingham
Astha Anand - Collaborator - University of Birmingham
Shamil Haroon - Collaborator - University of Birmingham
Christopher Sainsbury - Collaborator - University of Birmingham
Dr Neeraj Bhala - Collaborator - University of Birmingham

Linkages: 
HES Admitted;ONS;CHESS;SGSS;ICNARC;Practice IMD;Patient Townsend