Rheum caught up in long covid symptom muddle

3 minute read

Symptoms used to define post-covid condition 'might constitute a reservoir of distress in our daily lives', according to Prof Leonard Calabrese.

A large Dutch study investigating long covid among patients with inflammatory rheumatic diseases has found that they’re more likely than healthy controls to experience post-covid condition.

However, after accounting for confounders – body mass index and severity of acute covid infection – there was little difference between rheumatic disease patients and healthy controls.

Additional analysis also suggested a significant overlap between experience of post-covid symptoms and symptoms associated with rheumatic disease, with the authors suggesting that the observed difference between rheumatic disease patients and healthy controls could be partly explained by clinical manifestations of underlying rheumatic diseases.

“We therefore conclude that inflammatory rheumatic disease patients are not more susceptible for long-COVID than people from the general population,” wrote the authors.

The prospective study, published in the Lancet Rheumatology and presented at EULAR 2023, was originally set up to assess the severity of covid in rheumatic disease patients compared with healthy controls. The long covid analysis was an extension of this study.

In accordance with the WHO guidelines, long covid was defined as symptoms that lasted at least eight weeks, that started after onset and within three months of PCR or antigen-confirmed covid, and that could not be confirmed by an alternative diagnosis.

Almost 2000 rheumatic disease patients from the Amsterdam Rheumatology and Immunology Center were invited to take part in the study, and were matched with over 700 healthy controls.

Of these patients, 24% recorded an omicron covid infection, compared with 30% of healthy controls. Among those who contracted covid, 21% of rheumatic disease patients and 13% of healthy controls experienced long covid as defined by WHO criteria.

Symptoms of long covid and the recovery time were similar for patients with inflammatory rheumatic diseases and healthy controls. Fatigue, loss of fitness, difficulties with concentration, sleep disturbances and pain were the main symptoms reported.

However, as was also pointed out by Professor Leonard Calabrese in an accompanying comment, these symptoms are common among rheumatic disease patients, especially those with concomitant fibromyalgia, and may confound efforts to diagnose long covid on the basis of one unexplained symptom.

The lack of specificity of the symptoms was brought home in a retrospective survey of the cohort. It found 43% of the rheumatic disease patients and 33% of healthy controls who’d had covid experienced these symptoms within the previous two years, while among those who hadn’t had covid, 21% of rheumatic disease patients and 11% of healthy controls had also experienced them.

“This highlights the limitations of applying current criteria for post-COVID condition in patients with inflammatory rheumatic disease, and suggests it might be appropriate for physicians to keep a nuanced attitude when communicating the long-term consequences of COVID-19,” concluded the authors.

Pointing to a recent review that asserted there may be more than 200 symptoms that occur post covid, Professor Calabrese suggested that “such symptomatology might constitute a reservoir of distress in our daily lives, challenging their utility in assigning causality from an infection with the magnitude of the global prevalence of COVID-19”.

“Validated classification criteria for long COVID that can be used for comparative epidemiologic investigations and biomarker discovery are now urgently required,” wrote Professor Calabrese.

“The field of rheumatology has extensive experience in the development of disease-state classification criteria for disorders that are complex and have many overlapping features with long COVID that could serve as a model for such efforts.”

Lancet Rheumatology 2023, 31 May

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