Phenotyping of acute and persistent COVID-19 features in the outpatient setting: exploratory analysis of an international cross-sectional online survey

BACKGROUND

Long COVID, defined as presence of COVID-19 symptoms 28 days or more after clinical onset, is an emerging challenge to healthcare systems. The objective of this study was to explore recovery phenotypes in non-hospitalized COVID-19 individuals.

METHODS

A dual cohort, online survey study was conducted between September 2020 and July 2021 in the neighboring European regions Tyrol (TY, Austria, n = 1157) and South Tyrol (STY, Italy, n = 893). Data on demographics, comorbidities, COVID-19 symptoms and recovery adult outpatients were collected. Phenotypes of acute COVID-19, post-acute sequelae and risk of protracted recovery were explored by semi-supervised clustering and multi-parameter LASSO modeling.

RESULTS

Working age subjects (TY: 43 yrs (IQR: 31 – 53), STY: 45 yrs (IQR: 35 – 55)) and females (TY: 65.1%, STY: 68.3%) predominated the study cohorts. Nearly half of the participants (TY: 47.6%, STY: 49.3%) reported symptom persistence beyond 28 days. Two acute COVID-19 phenotypes were discerned: the non-specific infection phenotype and the multi-organ phenotype (MOP). Acute MOP symptoms encompassing multiple neurological, cardiopulmonary, gastrointestinal and dermatological complaints were linked to elevated risk of protracted recovery. The major subset of long COVID individuals (TY: 49.3%, STY: 55.6%) displayed no persistent hyposmia or hypogeusia but high counts of post-acute MOP symptoms and poor self-reported physical recovery.

CONCLUSION

The results of our two-cohort analysis delineated phenotypic diversity of acute and post-acute COVID-19 manifestations in home-isolated patients which needs to be considered for predicting protracted convalescence and allocation of medical resources.