Long COVID prevalence and risk factors in adults residing in middle- and high-income countries: secondary analysis of the multinational Anti-Coronavirus Therapies (ACT) trials.

BACKGROUND

During the recent COVID-19 pandemic, reports of long-term persistence or recurrence of symptoms after SARS-CoV-2 infection emerged, which are now collectively referred to as 'long COVID'. Most descriptions of long COVID originate from patients residing in high-income countries. We set out to characterise long COVID in a large-scale clinical trial that was conducted in low-middle, high-middle and high-income countries.

METHODS

The Anti-Coronavirus Therapies trials enrolled 6528 adult patients with symptomatic COVID-19 in Argentina, Brazil, Canada, Colombia, Ecuador, Egypt, India, Nepal, Pakistan, Philippines, Russia, Saudi Arabia, South Africa and the United Arab Emirates. Long COVID was defined as the presence of patient-reported symptoms at 180 days after enrolment. Multivariable logistic regression was used to evaluate associations of baseline characteristics with long COVID.

RESULTS

Of 4697 included participants, 1181 (25.1%) reported long COVID symptoms. The most frequently reported symptoms were sleeping disorders (n=601; 12.8%), joint pain (n=461; 9.8%), fatigue (n=410; 8.7%) and headaches (n=382; 8.1%). Long COVID prevalence was higher in participants from lower middle-income compared with high-income countries (29.8% (850/2854) vs 14.4% (102/706); adjusted OR (aOR) 1.53 (1.10 to 2.14); p=0.012). Prevalence also varied between participants of different ethnic backgrounds and was highest (36.1% (775/2145)) for patients of Arab/North African ethnicity. Patients requiring inpatient admission were at increased risk of long COVID (aOR: 2.04 (1.63 to 2.54); p<0.001). Other independent predictors of long COVID were male sex, older age and hypertension. Vaccination, prior lung disease, smoking and diabetes mellitus conferred protective effects.

CONCLUSION

Symptoms of long COVID are reported in a quarter of cases of symptomatic COVID-19 in this study and were significantly more prevalent in participants from countries with lower income status and in patients of Arab/North African ethnicity. Research to further assess the health burden posed by long COVID in low- and middle-income countries is urgently needed.