Cluster analysis of long COVID symptoms for deciphering a syndrome and its long-term consequence, Niewolik et al, 2024

Cluster analysis of long COVID symptoms for deciphering a syndrome and its long-term consequence

Abstract
The long-term symptoms of COVID-19 are the subject of public and scientific discussions. Understanding how those long COVID symptoms co-occur in clusters of syndromes may indicate the pathogenic mechanisms of long COVID.

Our study objective was to cluster the different long COVID symptoms. We included persons who had a COVID-19 and assessed long-term symptoms (at least 4 weeks after first symptoms).

Hierarchical clustering was applied to the symptoms as well as to the participants based on the Euclidean distance h of the log-values of the answers on symptom severity. The distribution of clusters within our cohort is shown in a heat map.

From September 2021 to November 2023, 2371 persons with persisting long COVID symptoms participated in the study. Self-assessed long COVID symptoms were assigned to three symptom clusters.
Cluster A unites rheumatological and neurological symptoms, cluster B includes neuro-psychological symptoms together with cardiorespiratory symptoms, and a third cluster C shows an association of general infection signs, dermatological and otology symptoms.

A high proportion of the participants (n = 1424) showed symptoms of all three clusters. Clustering of long COVID symptoms reveals similarities to the symptomatology of already described syndromes such as the Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) or rheumatological autoinflammatory diseases. Further research may identify serological parameters or clinical risk factors associated with the shown clusters and might improve our understanding of long COVID as a systemic disease. Furthermore, multimodal treatments can be developed and scaled for symptom clusters and associated impairments.

My bolding

https://pubmed.ncbi.nlm.nih.gov/38627327/#full-view-affiliation-2


https://link.springer.com/article/10.1007/s12026-024-09465-w

 

This is really significant. It's clearly fashionable to try to make up clusters here, lots of studies doing this, but given the fluctuating nature, using single points in time is highly problematic, and that's in addition to how much overlap there is. I'm not sure they are really that important. Other perhaps than recognizing how widely varied it all is and how it should restrict the range of possible mechanisms.

Can they? It seems to be the usual throwaway but it never seems to be considered that current approaches aren't up for standard and something fundamental needs to change here. Winging it with rehabilitation will not work. Winging it with rehabilitation seems to be the default approach, the only approach. So is widespread failure at influencing outcomes. At some point experts are expected to get their heads out of their asses, but that point was several decades ago so I don't know how we go from there when that paradigm shift is rejected like it's religious dogma.

Oddly, the problem is basically differential diagnosis. It doesn't work here. It's the main diagnostic methodology. In fact pretty much the only one. The algorithm of psychosomatic ideology is that when differential diagnosis fails, you have to assume psychosocial whatever, which only compounds the failure.