Trial Report Physiological presentation and risk factors of long COVID in the UK using smartphones and wearable devices…, 2024, Stewart+

Physiological presentation and risk factors of long COVID in the UK using smartphones and wearable devices: a longitudinal, citizen science, case–control study
Callum Stewart; Yatharth Ranjan; Pauline Conde; Shaoxiong Sun; Yuezhou Zhang; Zulqarnain Rashid; Heet Sankesara; Nicholas Cummins; Petroula Laiou; Xi Bai; Richard J B Dobson; Amos A Folarin

BACKGROUND
The emergence of long COVID as a COVID-19 sequela was largely syndromic in characterisation. Digital health technologies such as wearable devices open the possibility to study this condition with passive, objective data in addition to self-reported symptoms. We aimed to quantify the prevalence and severity of symptoms across collected mobile health metrics over 12 weeks following COVID-19 diagnosis and to identify risk factors for the development of post-COVID-19 condition (also known as long COVID).

METHODS
The Covid Collab study was a longitudinal, self-enrolled, community, case–control study. We recruited participants from the UK through a smartphone app, media publications, and promotion within the Fitbit app between Aug 28, 2020, and May 31, 2021. Adults (aged ≥18 years) who reported a COVID-19 diagnosis with a positive antigen or PCR test before Feb 1, 2022, were eligible for inclusion. We compared a cohort of 1200 patients who tested positive for COVID-19 with a cohort of 3600 sex-matched and age-matched controls without a COVID-19 diagnosis.

Participants could provide information on COVID-19 symptoms and mental health through self-reported questionnaires (active data) and commercial wearable fitness devices (passive data). Data were compared between cohorts at three periods following diagnosis: acute COVID-19 (0–4 weeks), ongoing COVID-19 (4–12 weeks), and post-COVID-19 (12–16 weeks). We assessed sociodemographic and mobile health risk factors for the development of long COVID (defined as either a persistent change in a physiological signal or self-reported symptoms for ≥12 weeks after COVID-19 diagnosis).

FINDINGS
By Aug 1, 2022, 17 667 participants had enrolled into the study, of whom 1200 (6·8%) cases and 3600 (20·4%) controls were included in the analyses. Compared with baseline (65 beats per min), resting heart rate increased significantly during the acute (0·47 beats per min; odds ratio [OR] 1·06 [95% CI 1·03–1·09]; p<0·0001), ongoing (0·99 beats per min; 1·11 [1·08–1·14]; p<0·0001), and post-COVID-19 (0·52 beats per min; 1·04 [1·02–1·07]; p=0·0017) phases. An increased level of historical activity in the period from 24 months to 6 months preceding COVID-19 diagnosis was protective against long COVID (coefficient –0·017 [95% CI –0·030 to –0·003]; p=0·015). Depressive symptoms were persistently elevated following COVID-19 (OR 1·03 [95% CI 1·01–1·06]; p=0·0033) and were a potential risk factor for developing long COVID (1·14 [1·07–1·22]; p<0·0001).

INTERPRETATION
Mobile health technologies and commercial wearable devices might prove to be a useful resource for tracking recovery from COVID-19 and the prevalence of its long-term sequelae, as well as representing an abundant source of historical data. Mental wellbeing can be impacted negatively for an extended period following COVID-19.

FUNDING
National Institute for Health and Care Research (NIHR), NIHR Maudsley Biomedical Research Centre, UK Research and Innovation, and Medical Research Council.


Link | PDF (The Lancet Digital Health) [Open Access]

 

I haven't read all of the paper but this popped out to me first: self reported valence is one of the metrics gathered in this study.

Valence also known as hedonic tone, is a characteristic of emotions that determines their emotional affect (intrinsic appeal or repulsion). https://en.wikipedia.org/wiki/Valence_(psychology)

There is debate in psychology about it's constructiveness etc of using it in research:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10514250/

They also measure self reported arousal. Which can mean many things, but I suppose they are looking for trends.

I note it is in collaboration with the Maudsley (a famous psychiatric unit in London, well-known for it's psychotherapeutic approaches to mental health disorders eg family therapy for anorexia nervosa, taught worldwide)

I see a connection has been made with depressive symptoms during the pandemic and they consider it as a potential risk factor for LC.

So not a risk factor but who knows someone will mis-quote this and make it so...

If you were more active and fit with a lower resting HR, this was a protective factor for LC

I am cynically thinking that these themes sound familiar and BPS will be very interested in inserting this study into their presentations. It has a big sample size.

Of course these self-enrolled, case control studies have some potential biases. You have to have mobile technology and a wearable device and 1) be interested and 2) be motivated to record and share your metrics. It was promoted through the Fitbit app (so maybe they have narrowed their sample to not include Apple users, though I have just read that they acknowledge that)