Agreement and reliability between the 2-day 6-minute incremental step test & 2-day cardiopulmonary exercise test in LC for assessing PEM, 2026, Bomans

[Chandelier]

Agreement and reliability between the two-day 6-minute incremental step test and two-day cardiopulmonary exercise test in post COVID-19 condition for assessing post-exertional malaise: The REVEAL-study

Spoiler: Authors

Bomans, Sarah; Michotte, Naomi; El M’Rabet, Imane; Jimenez Garcia, Berenice; Leemans, Lynn; Janssens, Peter; Hanon, Shane; De Waele, Elisabeth; Beckwée, David

Abstract​

Background​

Post-Exertional Malaise (PEM) is a core symptom of post COVID-19 condition (also known as long COVID) affecting millions of people, yet assessment remains challenging.
The two-day cardiopulmonary exercise test (CPET) is the current gold standard for objectifying PEM, but its cost and patient burden limit use.
The two-day 6-minute incremental step test (6MIST) with wireless wearable sensors could offer a more accessible alternative.

Methods​

This cross-over study (n = 25, one-month washout period) evaluated the level of agreement and reliability between the two-day 6MIST and the two-day CPET for assessing PEM.
Each “two-day” test consisted of two identical exercise tests separated by 24 hours to capture worsening of symptoms on day 2.
Objective (VO2peak) and subjective (fatigue, neuromuscular complaints and rated perceived exertion) PEM outcomes were collected.
Subjective outcomes were measured in relation to the first exercise test of each two-day session; at 15 minutes pretest, 15 minutes posttest and 24 hours posttest, with changes analyzed as Δ1 (baseline to 15 minutes posttest) and Δ2 (15 minutes posttest to 24 hours posttest).
Agreement was assessed using Bland-Altman plots and reliability through consistency Intraclass Correlation Coefficients.

Results​

VO2peak and neuromuscular complaints showed low agreement and reliability between the two tests.
Rated perceived exertion showed moderate reliability at all times and fatigue showed moderate reliability for changes after 24h (Δ2).

Conclusions​

Contrary to our hypothesis, the two-day 6MIST shows limited agreement with the two-day CPET overall.
However, moderate reliability for rated perceived exertion and fatigue suggests potential for improvement with protocol refinement.
Further research is needed to optimize the two-day 6MIST and to develop assessments that capture PEM both within and beyond the 24-hour period.

Web | DOI | PMC | PDF | PLOS One

 

[Hutan]

There are a lot of problems with this.

The two-day cardiopulmonary exercise test (CPET) is the current gold standard for objectifying PEM, but its cost and patient burden limit use.

Currently, the most valid tool for assessing PEM in ME/CFS objectively is the two-day Cardiopulmonary Exercise Test (CPET), which triggers PEM under controlled conditions [

No, it isn't. I think the authors are confusing post-exertion effects with PEM. People are not necessarily in PEM during the second CPET. In fact, they probably aren't in PEM, because, if they were, they would not make it to the lab and do the test.

The two-day 6-minute incremental step test (6MIST) with wireless wearable sensors could offer a more accessible alternative.

Building on the established use of field-based functional tests, one promising option is the 6-minute incremental step test (6MIST) with wearable wireless sensor devices [15]. The 6MIST is a maximal exercise test which involves high knee stepping, with a metronome guiding the rhythm and accelerating every 30 seconds [15]. It’s important to note that the 6MIST is designed to be a patient-friendly test that can be performed with minimal equipment in many settings, both in and outside the hospital. Because of these advantages, the two-day 6MIST represents a possible alternative to the two-day CPET.

If the test is more patient-friendly than a CPET, then frankly it is even less likely to trigger on-demand PEM. I think it might be a useful test of the impact of repetitive use of muscles, and perhaps even a way to produce some exertion-induced biochemical changes. But I think the researchers need to get away from the idea that they can trigger PEM to order.

It often greatly affects an individual’s daily functioning and social life, potentially leading to further disability and reinforcing a negative cycle

reinforcing a negative cycle - ugh

 

[Turtle]

"on demand PEM" that 's a nice one @Hutan .
A pity these authors won't recognise it when they see it, patients know.