Identifying subtypes of Long COVID: a systematic review

Area of Science:

• Medical Research
• Public Health
• Infectious Diseases

Background:

• Long COVID presents diverse, persistent symptoms post-SARS-CoV-2 infection.
• Effective management requires understanding and classifying patient subtypes.

Purpose of the Study:

• To systematically review and summarize existing approaches for clustering and classifying Long COVID patients and symptoms.
• To support improved clinical management strategies for Long COVID.

Main Methods:

• Systematic literature search (PubMed, Embase, Web of Science, Google Scholar) following PRISMA guidelines.
• Data extraction and quality assessment of eligible studies.
• Analysis of symptom co-occurrence networks and meta-analysis of organ system-based symptom clusters.

Main Results:

• Included 64 studies (47 cohort, 17 cross-sectional) with 2.43 million participants.
• Identified four major categorization approaches: symptom co-occurrence (46.9%), organ system (25.0%), severity (14.1%), and clinical indicators (4.7%).
• Fatigue, olfactory-gustatory dysfunction, anxiety-depression, and joint/muscle pain were common symptom clusters/dyads. Respiratory (47%), neurological (31%), and gastrointestinal (28%) symptom clusters were most prevalent.

Conclusions:

• Symptom co-occurrence and organ system involvement are primary methods for Long COVID classification.
• Fatigue and olfactory-gustatory dysfunction are recurrent core symptoms across Long COVID subtypes.
• Understanding these classifications aids in targeted Long COVID management and research.