Characterisation, Symptom Pattern and Symptom Clusters from a retrospective Cohort of Long COVID Patients in Primary Care in Catalonia.

Gemma Torrell, Diana Puente, Constanza Jacques Aviñó, Israel Rodriguez-Giralt, Lucía Amalia Carrasco-Ribelles, Concepció Violán Flors, Veronica Royano, Alba Molina Cantón, Tomás López Jiménez, Laura Medina Perucha, Anna Berenguera

Keywords: SARS-CoV-2, Long COVID, post-COVID-19 syndrome, cluster analysis, primary health care, participatory research.

Background:

Around 10% of people infected by SARS-COV-2 report symptoms that persist longer than three months. Little has been reported about sex differences in symptoms and clustering over time of non-hospitalised patients in primary care settings.

Research questions:

Which are the characteristics and evolution of symptoms over time in patients with Long COVID visited at primary care settings in Catalonia?

Method:

Descriptive study of a primary care cohort of patients with symptoms' persistence ≥3 months from clinical onset in co-creation with the Long Covid Catalan group using an online survey. Recruitment: March 2020 -June 2021. Exclusion criteria: being admitted to ICU, <18 years old, not living in Catalonia. 117 symptoms were gathered in 18 groups. A cluster analysis was performed at 21 days of infection (baseline), 22-60 days and ≥ 3 months.

Results:

We analysed responses of 905 participants (80.3% women). General symptoms were the most prevalent with no differences by sex, age, or wave. Its frequency decreased over time. Dermatological (52.1% in women, 28.5% in men), olfactory (34.9%, 20.9%) and neurocognitive symptoms (70.1%, 55.8%) showed the greatest differences by sex. Cluster analysis showed five clusters with a predominance of Taste&smell (24.9%) and Multisystemic clusters (26.5%) at baseline and Multisystemic (34.59%) and Heterogeneous (24.0%) at ≥3 months. Multisystemic cluster was more prevalent in men. Menstrual cluster was the most stable. Most transitions occurred from Heterogeneous cluster to Multisystemic cluster and from Taste&Smell to Heterogeneous.

Conclusions:

General symptoms were the most prevalent in both sexes at three-time cut-off points. Major sex differences were observed in dermatological, olfactory and neurocognitive symptoms. The increase of Heterogeneous cluster might suggest an adaptation to symptoms or a non-specific evolution of the condition which can hinder its detection at medical appointments. A carefully symptom collection and patients’ participation in research may generate useful knowledge about Long Covid presentation in primary care settings.

Points for discussion:

Affected people participation in research. How, when, why.

Can clustering help to identify patients with Long COVID at clinical appointments?

When a disease is not yet well defined, how to perform an evidence-based practice?

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