Assessment of 115 symptoms for Long COVID (post-COVID-19 condition) and their risk factors in non-hospitalised individuals: a retrospective matched cohort study in UK primary care

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS CoV-2) infection is frequently associated with a wide range of persistent symptoms, now referred to as post-COVID-19 condition, or Long COVID. The objectives of this study were to assess which symptoms are associated with confirmed SARS CoV-2 beyond 12 weeks post-infection in non-hospitalised individuals, and the risk factors associated with developing persistent symptoms. We undertook a retrospective matched cohort study between 31st January 2020 and 15th April 2021 using data from a large database of UK-based primary care electronic health records, Clinical Practice Research Datalink (CPRD) Aurum. We selected 486,149 adult patients with a confirmed diagnosis of SARS CoV-2 infection that had not been hospitalised within 28 days of the diagnosis (infected cohort). We propensity score matched them to 1,944,580 patients without a coded record of either confirmed or suspected COVID-19 (uninfected cohort). Outcomes were the presence of 115 separate symptoms at ≥12 weeks post-infection, and Long COVID, defined as having at least one of the symptoms included in the World Health Organisation case definition. Separate Cox proportional hazards models were used to estimate adjusted hazard ratios (aHR) for individual symptoms and Long Covid. 62 symptoms were significantly associated with prior exposure to SARS CoV-2 after 12 weeks. The largest adjusted hazard ratios (aHR) were for anosmia (aHR 6.49, 95% CI 5.02 to 8.39), hair loss (3.99, 3.63 to 4.39), sneezing (2.77, 1.40 to 5.50), difficulties with ejaculation (2.63, 1.61 to 4.28), reduced libido (2.36, 1.61 to 3.47), shortness of breath at rest (2.20, 1.57 to 3.08), fatigue (1.92, 1.81 to 2.03), pleuritic chest pain (1.86, 1.41 to 2.46), hoarse voice (1.78, 1.44 to 2.20), and fever (1.75, 1.54 to 1.98). Among the infected cohort, risk factors for Long COVID included younger age (aHR 0.75, 95% CI 0.70 to 0.81, for those aged ≥70 years compared to those aged 18 to 30 years), female sex (1.52, 1.48 to 1.56), belonging to an ethnic minority group (1.14 [1.07 to 1.22] for mixed race, 1.21 [1.10 to 1.34] for black ethnic groups, and 1.06 [1.03 to 1.10] for other ethnic minority groups, compared to white ethnic groups), socioeconomic deprivation (1.11 [1.07 to 1.16] for the most compared to the least socioeconomically deprived quintile), smoking (1.12, 1.08 to 1.15), obesity (1.10, 1.07 to 1.14), and a wide range of comorbidities such as COPD. SARS CoV-2 in non-hospitalised individuals is associated with a plethora of symptoms being reported at ≥12 weeks post-infection, with a higher risk associated with younger age, female sex, ethnic minority groups, socioeconomic deprivation, smoking, obesity, and several comorbidities.