JMIR Publications

ABSTRACT

Background:

While electrocardiography is the gold standard for heart rate (HR) recording in clinical trials, the increasing availability of smartwatch-based HR monitors opens possibilities in drug development studies. Smartwatches allow cheap, unobtrusive, and continuous HR estimation and can be used to detect treatment effects outside the clinic, during daily living.

Objective:

This study evaluates the repeatability and sensitivity of smartwatch-based HR estimates in a randomized clinical trial.

Methods:

The data were collected as part of a multiple-dose, investigator-blinded, randomized, placebo-controlled, parallel-group study in 12 patients with Parkinson’s Disease. After a 6-day baseline period, patients were treated either with placebo or an ascending dose of clenbuterol for 7 days. Smartwatch HR estimates were collected throughout the study period and quantified as the 2.5, 50.0, and 97.5 percentiles while awake and while asleep. The intra-class correlation (ICC), minimal detectable effect (MDE), and effect-sizes (ESs) were calculated using linear mixed models.

Results:

Clenbuterol induced changes were detected in the asleep HR as of the first night (3.79 bpm, p < .01) and in the awake HR as of the third day (8.79 bpm, p < .01). The median HR while asleep had the highest repeatability with an ICC of .70. The MDE (N=12) was found to be smaller when patients were asleep (6.8 – 11.7 bpm) than while awake (10.7 – 22.1 bpm). Overall, the ESs to clenbuterol-induced changes were higher while asleep (0.49 – 2.75) than while awake (0.08 – 1.94).

Conclusions:

Here, we showed how continuous smartwatch-HR estimates can be used to detect drug-induced changes during clinical trials. The asleep HR-estimates were most repeatable and sensitive to treatment effects. We conclude that smartwatch obtained HR during daily living in a clinical trial can be used to detect and track treatment effects. Clinical Trial: Netherlands Trials Register (trialregister.nl) NL8002