BACKGROUND AND PURPOSE:

• While widely reported, there have been very few studies on the features of ‘Long-COVID’, and how they related to age, sex, or severity of infection
• Taquet et al. (PLoS Medicine, 2021) estimated the incidence and co-occurence of long-COVID features, and relationship to demographic and clinical factors

METHODS:

• Retrospective cohort study
• Population
  • 81 million patients, mostly in the US
  • TriNetX Analytics: Linked EHRs | Anonymized data from 59 healthcare organizations (HCOs)
• Exposures
  • COVID-19
  • Influenza
• Study design
  • Incidence and co-occurrence of features within 6 months and in the 3 to 6 months after COVID-19 diagnosis
  • 9 core COVID-19 features: Breathing difficulties/breathlessness | Fatigue/malaise | Chest/throat pain | Headache | Abdominal symptoms | Myalgia | Other pain | Cognitive symptoms | Anxiety/depression
  • COVID-19 patients were propensity score-matched to a cohort of patients diagnosed with influenza during the same time period for comparison
  • Incidence of atopic dermatitis was used as a negative control
• Primary outcome
  • Incidence and co-occurrence of features of long-COVID

RESULTS:

• COVID-19 survivors: 273,618
  • Mean (SD) age: 46.3 (19.8) years | 55.6% female
• Individuals with long-COVID features recorded
  • During the entire 6-month period: 57%
  • During the 3-to-6-month period: 36.55%
• Incidence of long-COVID features
  • Abnormal breathing
    • In 6-month period: 18.71%
    • In 3-to-6-month period: 7.94%
  • Fatigue/malaise
    • In 6-month period: 12.82%
    • In 3-to-6-month period: 5.87%
  • Chest/throat pain
    • In 6-month period: 12.60%
    • In 3-to-6-month period: 5.71%
  • Headache
    • In 6-month period: 8.67%
    • In 3-to-6-month period: 4.63%
  • Other pain
    • In 6-month period: 11.60%
    • In 3-to-6-month period: 7.19%
  • Abdominal symptoms
    • In 6-month period: 15.58%
    • In 3-to-6-month period: 8.29%
  • Myalgia
    • In 6-month period: 3.24%
    • In 3-to-6-month period: 1.54%
  • Cognitive symptoms
    • In 6-month period: 7.88%
    • In 3-to-6-month period: 3.95%
  • Anxiety/depression
    • In 6-month period: 22.82%
    • In 3-to-6-month period: 15.49%
• All 9 features were more frequently reported after COVID-19 than after influenza (P<0.001)
  • Overall excess incidence: 16.60%
• Long-COVID features also co-occurred more commonly after COVID-19 than after influenza, and formed a more interconnected network
• Significant differences in incidence and co-occurrence were associated with sex, age, and illness severity
  • Incidence of “any” long-COVID feature ranged based on age
    • 10 to 21 years: 46.42%
    • >65 years: 61.05%
  • Females: More likely to have headaches, abdominal symptoms, and anxiety/depression
  • Males: More likely to have breathing difficulties and cognitive symptoms
  • Illness severity: Associated with more features overall

CONCLUSION:

• Clinical features of long-COVID were reported in 57% of patients within 180 days after infection
• These features occurred and co-occurred more frequently after COVID-19 than after influenza
• There were different clinical profiles of long-COVID based on demographics and illness severity

Learn More – Primary Sources:

Incidence, co-occurrence, and evolution of long-COVID features: A 6-month retrospective cohort study of 273,618 survivors of COVID-19

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