Digital physiological biomarkers predict within-person symptom changes in complex chronic illness, 2026, Aitken et al

[forestglip]

Abstract changed as well:

Digital physiological biomarkers predict within-person symptom changes in complex chronic illness

Spoiler: Authors

Aitken, Annie; Sawyer, Abbey; Iwasaki, Akiko; Krumholz, Harlan M.; Preston, Rory; Calcraft, Paul; Leeming, Harry; Tosto-Mancuso, Jenna; Proal, Amy; Osborne, Michael A.; Putrino, David

Abstract
Altered heart‑rate variability (HRV) and resting heart rate (HR) are common in many complex chronic conditions. Mobile and wearable technologies now provide real-time, valid measurements of HRV and HR, advancing symptom monitoring and management.

The current study integrates a 60-s morning PPG assessment with evening symptom severity reports, yielding a high-density mobile health dataset (n = 4244) with an average of 125 biometric observations per participant. We examined whether within-person fluctuations in HR, HRV, and respiratory rate predicted daily changes in crash, fatigue, and brain fog symptoms and secondarily evaluated model predictive performance.

Model fit and variance explained were highest in models that included morning biometrics in addition to prior-day symptom reports and covariates. Within-person increases in HR and decreases in HRV in the morning were associated with worsening symptom reports in the evening. Walk-forward cross-validation showed a statistically significant improvement in model performance when morning biometrics were added to prior-day symptom reports (AUC = 0.82–0.85 vs. 0.73–0.83).

These findings represent the prospective utility of mobile health tools for precision monitoring and prediction of real-time symptom exacerbations in complex chronic illness.

Web | DOI | PDF | npj Digital Medicine | Open Access

 

[Utsikt]

What they are missing: the participants’s morning prediction of evening symptoms. We have no idea if this is better than what you can manage on your own.

 

[Jonathan Edwards]

They seem to be measuring raised heart rte and reduced HRV for a short period in the morning. That is presumably not going to reflect any episodes of exertion during the day. So it will not be a measure of how much you have overdone things, just a measure of maybe it being a bad day on which to do things. But to be sure that actually was the case I think you would need to show that exerting on those days really did produce more PEM than other days.

That seems to get a bit too complicated.

And presumably you cannot do much about the fact that your heart thinks it is a bad day to do stuff when it does.

I keep getting this sense that people have borrowed these measurements from the old deconditioning model and that a model of what exertion determines PEM needs to start afresh.

 

[Utsikt]

They seem to be measuring raised heart rte and reduced HRV for a short period in the morning.

If it’s from Visible, you’re supposed to take a reading first time in the morning. I tried re-doing mine a few minutes later and they gave vastly different results.

 

[Jonathan Edwards]

If it’s from Visible, you’re supposed to take a reading first time in the morning. I tried re-doing mine a few minutes later and they gave vastly different results.

And wouldn't the result for that first minute depend on whether you were already feeling grumpy and trying to wash your face when the water was too cold or whether the sun was shining and someone had brought you a special cake for breakfast in bed? I can't quite get my head around how this is going to be any use.

 

[Jonathan Edwards]

I have often wondered when the day will come when computers rule the world and we are just their servants tending to their needs while foolishly thinking we are still in charge.

A little while ago I realised that that day already came.