(109) Incidence Rate of Long COVID Among Overweight or Obese Adults Who Had COVID-19 Infection in the United Kingdom

Background: Estimates of prevalence of long COVID vary widely globally. In the UK, 1.9% of the UK population were experienced self-reported long COVID as of March 2023. A previous study showed that obesity (defined as ≥30 kg/m2) was associated with a high risk of developing long COVID among the COVID infected individuals. However, no study estimated the incidence rate of long COVID among overweight/obese patients.

Objectives: To estimate the annual incidence rate of long COVID among COVID-19 infected patients who were overweight/obese

Methods: A population-based cohort study was conducted using the Clinical Practice Research Datalink (CPRD) Aurum, an anonymised largest UK primary care database. We included individuals aged ≥18 with a diagnostic code record of SAR-CoV-2 infection in their health records between March 2020 and July 2023, who were overweight or obese (body mass index ≥ 25 kg/m2).
The primary outcome of long COVID was defined as having a post-COVID-19 syndrome diagnostic code within 1 year after the COVID-19 diagnosis date. Individuals were followed up to 1 year after their COVID-19 infection date. We estimated the incidence rate of long COVID with a 95% confidence interval (CI), using the first occurrence of long COVID event in the individual's health record as the numerator and the number of patients at risk as the denominator by the time at risk using the Poisson regression.

Results: 8,037 long COVID patients were identified among 763,363 COVID infected adults who were overweight or obese. Among long COVID patients, 65.4% were female, and the average age at COVID-19 diagnosis was 51.1 years. Of these individuals, 56.42% were obese (BMI ≥30 kg/m²) while 43.57% were overweight (BMI 25-29.9 kg/m²).
The incidence rate of long COVID exhibited a declining trend over the study period. In 2020, the incidence rate was highest at 2.14 per 100 person-years (95% CI 2.02-2.27). This rate decreased to 1.11 per 100 person-years (95% CI 1.08-1.12) in 2021, followed by further declines to 0.48 per 100 person-years (95% CI 0.46-0.51) in 2022 and 0.22 per 100 person-years (95% CI 0.16-0.30) in 2023. The overall reduction rate was nearly 10 times from 2020 to 2023.

Conclusions: Incidence rate of long COVID among COVID infected adults who were overweight or obese declined over the study period. Further research is encouraged to study the clinical outcome of long COVID as this will enhance our understanding and management of long COVID in the community.