How to report findings that sick people are more sick

[Midnattsol]

Inspired by the thread "Correlation of fatigue with disability and accelerometer-measured daily physical activity in patients with relapsing-remitting MS 2023 Luostarin et al" with this apt comment from @Trish

So have they simply found that those who are less sick are less sick?

This seem to be a common but not surprising finding in studies that look at functional capacity and illness - those who are less severely ill also have a higher functional capacity and are for example more physically active. Cue that the physical activity is the reason for the higher functional capacity, and that severely ill patients should be encouraged to increase their physical activity level to become more like their less severe counterparts. Typically glossing over that illness severity impedes the ability to be physically active.

What would be a better way to represent such findings?

 

[Trish]

I think the key here is that this is not a clinical trial or longitudinal study where the effect of increasing or decreasing exercise can be deduced. It is a one time study of symptoms and activity levels.

So it's really the old correlation is not causation problem, with the direction of causation being interpreted to suit the prejudices of the people writing the conclusions.

It's like the political thing that arose in the UK about 20 or more years ago that showed that people in employment had better health than people who were on sickness benefits, so the daft conclusion was made that work is good for health.

A better way to represent findings is to make it absolutely clear that the likely direction of causation is that sicker people are less able to be so active because the disease is debilitating, with the example of how people behave and how fatigued they feel when they have flu.

The MS disability scale that I posted on another thread today demonstrates this. It uses distance people with MS are able to walk as a key measure of severity of disease.
https://www.s4me.info/threads/corre...ng-ms-2023-luostarin-et-al.34474/#post-486634

 

[Kitty]

A lower disability rate, better physical condition, and higher daily-living activity were found to predict lower fatigue levels.

In this instance, I can't decide whether the study is trying to suggest that people should be encouraged to exercise more.

It might be doing that. Alternatively, it might be reporting that fatigue is an additional impairment that these patients have to deal with, on top of their other MS symptoms.

Either way it's stating the bleeding obvious, but not necessarily in a negative way. (Unless of course the authors are known BPS practitioners, in which case I withdraw my case, m'lud!)

 

[Kitty]

What would be a better way to represent such findings?

I forgot to answer the question as usual.

I think when representing findings like this, there has to be acknowledgement of a tipping point.

people in employment had better health than people who were on sickness benefits, so the daft conclusion was made that work is good for health.

Work is good for health in many ways. But there comes a point where a person's level of impairment means the balance shifts, and instead of being beneficial, work becomes detrimental to their health. Everybody knows that.

It's the exactly same with exercise. Everybody knows that too.

The problem seems to be that common sense isn't fashionable in academic research and political soundbites.

 

[Midnattsol]

In this instance, I can't decide whether the study is trying to suggest that people should be encouraged to exercise more.

Not necessarily, but for example this quote that was shared in the thread: "A lower disability rate, better physical condition, and higher daily activity predicted lower fatigue levels. Thus, a suitable form of exercise should be found for MS patients, considering their functional capacity, to maintain their ability to function as well as possibly reduce their incidence of fatigue." can easily be misused to say patients need to exercise more. That the exercise should be "suitable" and "considering their functional capacity" are nuances that doesn't always make it when patients are being advised what to do.

I'm not sure if I think it's beneficial that often the presented solution includes finding "exercises", especially when we don't know exactly why they are less active to begin with. Finding exercises, to me, seem to have an underlying idea that the patients would be able to do exercise, but that they don't and this must be fixed.