Increased daily step count improves symptom control, physical function in heart failure
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Key takeaways:
- Smartwatch-measured step count is associated with health status at baseline and over time for people with heart failure.
- A 1,000-step increase in activity may be clinically important.
Among people with HF who wore daily activity trackers, an increase of 2,000 steps per day was associated with improved physical limitation scores compared with those who did not change their step counts, data show.
The FDA has endorsed the use of patient-reported health status outcomes to support regulatory approval for HF therapies, but not data from wearable devices, Brahmajee K. Nallamothu, MD, professor of internal medicine (cardiology) at the University of Michigan Medical School, and colleagues wrote in JACC: Heart Failure. The HF Academic Research Consortium, a partnership among the FDA, governmental agencies, patients and the HF community, provides guidance on the use of patient-reported and functional outcomes, such as actigraphy, as part of clinical trials.
Image: Adobe Stock
“It is not a surprise to anyone that there has been growth in wearables like smartwatches, as well as mobile health apps that work with these devices,” Nallamothu told Healio. “Despite their ubiquitous nature, there has been a lack of strong evidence linking what these wearable devices are telling us to established health measures. This is particularly true for patients with heart disease, like HF. This study, which was embedded within a clinical trial, was a good opportunity to see how these measures from wearable devices correlate with more established measures of health, like the Kansas City Cardiomyopathy Questionnaire.”
Data from daily activity trackers
Nallamothu and colleagues analyzed data from 425 adults with HF who participated in CHIEF-HF, a randomized controlled trial assessing the efficacy of the SGLT2 inhibitor canagliflozin (Invokana, Janssen) on health status, measured by the Kansas City Cardiomyopathy Questionnaire (KCCQ) and functional performance using a wearable device. Within the cohort, 44.5% of participants were women, 40.9% had HF with reduced ejection fraction and 27.5% had type 2 diabetes. Participants received a Fitbit Versa 2 and completed serial KCCQs via a smartphone app. Researchers evaluated the relationship between daily step count and floors climbed and KCCQ total symptom and physical limitation scores at baseline and their respective changes between 2 and 12 weeks.
At 2 weeks, the mean KCCQ total symptom score was 62.7 and the mean KCCQ physical limitation score was 55.7. KCCQ total symptom scores increased by an average of 2.5 points and KCCQ physical limitation scores by an average of 4 points through 12 weeks.
Baseline daily step count increased across categories of KCCQ total symptom scores, from 2,437.6 steps per day for scores ranging from 0 to 24 vs. 4,870.9 steps per day for scores ranging from 75 to 100 (P < .001). Results were similar for KCCQ physical limitation scores.
Compared with participants who walked 2,000 steps per day, those who walked 1,000 steps per day had KCCQ total symptom scores that were 3.11 points lower (95% CI, –1.05 to –5.17; P = .003); however, participants who walked 3,000 steps per day had KCCQ total symptom scores that were 2.89 points higher (95% CI, 1.04-4.73; P < .001).
Similarly, compared with participants who walked 2,000 steps per day, those who walked 1,000 steps per day had KCCQ physical limitation scores that were 5.36 points lower (95% CI, –7.39 to –3.33; P < .001), and those who walked 3,000 steps per day had KCCQ physical limitation scores that were 4.97 points higher (95% CI, 3.15- 6.79; P < .001).
Daily floors climbed was not significantly different across the 25-point ranges of KCCQ physical limitation scores (P = .137) or KCCQ total symptom scores (P = .218).
“Some findings were not unexpected; people who generally move more tend to have higher scores in terms of health status measures,” Nallamothu said during an interview. “What was surprising is if you do increase your daily average step count over this 12-week study period, it seemed to be associated with improvement in health status. There is not a lot of longitudinal data on this. The relationship was not always simple or linear; there was almost a nonlinear aspect. If you a decrease in step counts over time, that didn’t necessarily translate to a decrease in health status. We thought about this a lot and one explanation may be activities like travel or a holiday can impact daily step count during a short period of time.”
‘Much more to learn’ about step counts
In an adjusted nonlinear model, change in daily step count was associated with change in KCCQ total symptom scores from baseline through 12 weeks (P = .004), with a strong association for increases in step counts and KCCQ scores, but little association with decreases in step count, according to the researchers.
Researchers did not observe any between-group differences in a sensitivity analysis accounting for the impact of HF phenotype.
Nallamothu said the study design provides unique insights for researchers and clinicians.
“This is just a step in the direction of a promising future when we think about these technologies, but only a small step,” Nallamothu told Healio. “We have these devices; patients are coming to us with information from these devices and they are asking us: What can we make of these data? Right now, the jury is still out as to what these data really mean; however, this is a promising way to think about how to use this information to give us a little more knowledge on ways to partner with patients and better understand their health journey.”
For more information:
Brahmajee K. Nallamothu, MD, can be reached at bnallamo@med.umich.edu.
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