The pathogenesis of the long-lasting symptoms which can follow an infection with the SARS-CoV-2 virus (‘long covid’) is not fully understood. The ‘COroNaVirus post-Acute Long-term EffectS: Constructing an evidENCE base’ (CONVALESCENCE) study was established as part of the Longitudinal Health and Wellbeing COVID-19 UK National Core Study. We performed a deep phenotyping case-control study nested within two cohorts (the Avon Longitudinal Study of Parents and Children and TwinsUK) as part of CONVALESCENCE.

From September 2021 to May 2023, 349 participants attended the CONVALESCENCE deep phenotyping clinic at University College London. Four categories of participants were recruited: cases of long covid (long covid(+)/SARS-CoV-2(+)), alongside three control groups: those with neither long covid symptoms nor evidence of prior COVID-19 (long covid(-)/SARS-CoV-2(-); control group 1), those who self-reported COVID-19 and had evidence of SARS-CoV-2 infection, but did not report long covid (long covid(-)/SARS-CoV-2(+); control group 2) and those who self-reported persistent symptoms attributable to COVID-19 but no evidence of SARS-CoV-2 infection (long covid(+)/SARS-CoV-2(-); control group 3). Remote wearable measurements were performed up until February 2024.

This cohort profile describes the baseline characteristics of the CONVALESCENCE cohort. Of the 349 participants, 141 (53±15 years old; 21 (15%) men) were cases, 89 (55±16 years old; 11 (12%) men) were in control group 1, 75 (49±15 years old; 25 (33%) men) were in control group 2 and 44 (55±16 years old; 9 (21%) men) were in control group 3.

The study aims to use a multiorgan score calculated as the cumulative total for each of nine domains (ie, lung, vascular, heart, kidney, brain, autonomic function, muscle strength, exercise capacity and physical performance). The availability of data preceding acute COVID-19 infection in cohorts may help identify the consequences of infection independent of pre-existing subclinical disease and also provide evidence of determinants that influence the development of long covid.

Chest pain is a major cause of emergency ambulance calls, often linked to acute myocardial infarction (AMI), a critical condition requiring immediate hospitalisation. Current diagnostic methods, such as history taking and ECG, have limitations, especially for non-ST-elevation myocardial infarction. High-sensitivity cardiac troponin (cTn) assays are more diagnostically sensitive, but the downside is that it needs hospital-based testing, which can delay diagnosis and the necessary treatment protocol. Point-of-care cTn testing, on the other hand, is much faster and done nearer to the patient; hence, it may fundamentally change the prehospital care pathway in terms of diagnostic accuracy, clinical utility and related safety.

To present a protocol for a systematic review and meta-analysis that will assess the diagnostic accuracy, clinical utility and safety of point of care (POC) troponin tests, with or without clinical decision aids, for ruling out AMI in adults presenting with cardiac chest pain to emergency ambulance services in prehospital settings.

This protocol follows BMJ guidelines and adheres to the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols 2015 reporting standards. It is registered with PROSPERO (ID: CRD42024533117). A comprehensive search strategy will identify relevant studies in MEDLINE, EMBASE and CINAHL, focusing on literature from 2000 onwards. Eligibility criteria include adults with chest pain suspected of AMI, excluding those with ST-elevation myocardial infarction. The primary target is type 1 AMI, with secondary outcomes including major adverse cardiac events at 30 days. Risk of bias assessment will be performed using tools such as Quality Assessment of Diagnostic Accuracy Studies version 2, Risk of Bias 2, and Risk of Bias in Non-randomised Studies of Interventions, while the quality of the economic evaluations will be appraised using the Consolidated Health Economic Evaluation Reporting Standards (CHEERS) checklist. Data items extracted will include patient demographics, test characteristics and outcomes. Where possible, meta-analyses will be conducted by fitting hierarchical models for diagnostic accuracy and random effects models for clinical and cost-effectiveness estimates. Subgroup analyses are proposed to quantify the effect of variables such as gender, ethnicity and type of troponin assay on the estimated parameters.

Ethical approval is not required. The results will be published in a peer-reviewed journal and presented at international conferences.

This protocol is registered with PROSPERO, the International Prospective Register of Systematic Reviews, under the ID CRD42024533117. Any future amendments will be updated in the PROSPERO record.