Evidence mapPaperPMID 42415070Full record

Observational studyJournal of translational medicine2026

Persistent impairments in muscle function and symptom burden in post-COVID syndrome: a prospective longitudinal study.

Michael Wunderle, Andrea Ribeiro, Isabelle Lethen, Christoph Schmaderer, Timon Wallraven

Registry-linked trialAbstract readObservational Study
In one paragraph

Observational study in Journal of translational medicine, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT05635552 (All Eyes on PCS - Analysis of the Retinal Microvasculature in Patients With Post-COVID-19 Syndrome), which is not on this map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

NCT05635552 unknown statusnot on this map

All Eyes on PCS - Analysis of the Retinal Microvasculature in Patients With Post-COVID-19 Syndrome

TypeobservationalSponsorTechnical University of MunichRan2022 to 2023Enrolled300ConditionsLong Covid19, Post COVID-19 Condition, Endothelial DysfunctionArmsDynamic retinal vessel analysis (DVA), Optical coherence tomography (OCT), Biochemistry and immune phenotyping, Handgrip strength test, Questionnaires (Patient reported outcomes)
3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

5 authors.

Michael WunderleDepartment of Nephrology, TUM School of Medicine and Health, TUM University Hospital, Technical University of Munich, Munich, Germany. Michael.Wunderle@mri.tum.de.ORCID http://orcid.org/0000-0002-0460-5061
Andrea RibeiroDepartment of Nephrology, TUM School of Medicine and Health, TUM University Hospital, Technical University of Munich, Munich, Germany.
Isabelle LethenDepartment of Nephrology, TUM School of Medicine and Health, TUM University Hospital, Technical University of Munich, Munich, Germany.
Christoph SchmadererDepartment of Nephrology, TUM School of Medicine and Health, TUM University Hospital, Technical University of Munich, Munich, Germany.
Timon WallravenDepartment of Nephrology, TUM School of Medicine and Health, TUM University Hospital, Technical University of Munich, Munich, Germany.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundPost-COVID syndrome (PCS) is characterized by persistent heterogeneous symptoms after SARS-CoV-2 infection, yet objective biomarkers for symptom severity and longitudinal disease trajectories remain limited. We aimed to characterize muscle function over time in PCS and examine its relationship with symptom burden and neuroaxonal injury markers.

methodsIn this prospective observational study, patients fulfilling WHO criteria for PCS underwent standardized assessments at baseline (BL) and six-month follow-up (FU). Muscle function was assessed using a multidimensional handgrip strength (HGS) protocol capturing mean force (Fmean), fatigability (fatigue ratio), and recovery capacity alongside clinical symptom measures. Analyses included longitudinal assessment within the PCS cohort, comparisons with COVID-19 recovered controls, analysis of symptom persistence, and matched cohort analyses including HGS measures and circulating neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP).

resultsAmong 204 participants (102 PCS, 102 recovered controls) PCS patients showed lower Fmean and higher fatigability at BL and FU (both p < 0.01). Muscle function parameters remained largely stable over six months, with only modest improvement in recovery (p = 0.015). HGS parameters correlated with symptom burden (ρ ≈ -0.28 to -0.33), and BL impairments were associated with worse fatigue and depressive symptoms at FU (e.g., Fmean-PHQ-9: β = -0.11, p = 0.022; fatigue ratio-FSS: β = 1.66, p = 0.008). Exploratory analyses suggested slightly higher NfL and GFAP levels in PCS in some models, without consistent associations with muscle function or symptoms.

conclusionsHGS is persistently reduced in PCS over at least six months and aligns with symptom burden. Multidimensional HGS assessment may provide a practical objective marker of functional impairment and symptom persistence in PCS. Neuroaxonal injury markers showed modest elevations in PCS in some analyses but appeared unrelated to muscle performance, suggesting partially distinct mechanisms.

trial registrationClinicalTrials.gov, NCT05635552. Registered 1 December 2022 - Retrospectively registered, https://clinicaltrials.gov/study/NCT05635552?term=NCT05635552&rank=1&tab=study.

Indexed as

COVID-19AdultBiomarkersFatigueFemaleGlial Fibrillary Acidic ProteinHand StrengthHumansLongitudinal StudiesMaleMiddle AgedNeurofilament ProteinsPost-Acute COVID-19 SyndromeProspective StudiesSARS-CoV-2Symptom BurdenBiomarkersGlial Fibrillary Acidic Proteinneurofilament protein LNeurofilament ProteinsFatigabilityGFAPHandgrip strengthLong COVIDLongitudinal studyMuscle impairmentNeurofilament light chainPost-COVID syndrome

Identifiers

PMID42415070
PMCPMC13348007

What Socratic holds

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Registered trials

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the Socratic graph.