Daily step counts between 1,000 and 5,000 were significantly associated with symptoms and physical limitations, as reflected in Kansas City Cardiomyopathy Questionnaire (KCCQ) total symptom (TS) and physical limitation (PL) scores.
Participants whose step counts increased by 2,000 steps per day demonstrated a 5.2-point increase in their KCCQ-TS scores and a 5.33-point increase in their KCCQ-PL scores, with higher scores reflecting improvement.
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However, declines in step counts were not associated with significant declines in KCCQ-PL scores.
The findings are not yet ready to be implemented into practice, first author Jessica R. Golbus, MD, of the University of Michigan, Ann Arbor, said in an interview. However, she said, they “suggest that clinicians should interpret improvements in step counts as indicative of improving health status, though they should not necessarily be as concerned with reductions in step count.
“I would certainly, however, still encourage clinicians to discuss decrementing physical activity levels with their patients, though an intervention may not necessarily be warranted,” she added.
The study was published online in JACC: Heart Failure.
Nonlinear relationship
The investigators analyzed data from the Canagliflozin: Impact on Health Status, Quality of Life and Functional Status in Heart Failure (CHIEF-HF) trial, a randomized, controlled trial that enrolled participants with heart failure who had a smartphone.
Participants were given a Fitbit Versa 2 and completed serial KCCQs via the smartphone app.
The researchers assessed the relationship between daily step count and KCCQ-TS and KCCQ-PL scores at baseline, as well as changes in the scores between 2 and 12 weeks.
The study included 425 patients. The mean age was 63.5 years, 44.5% were women, and 83.3% were White; 40.9% had reduced ejection fraction, 59.1% had preserved ejection fraction, and 27.5% had type 2 diabetes.
At 2 weeks, the mean KCCQ-TS score was 62.7, and the mean KCCQ-PL score was 55.7.
KCCQ-TS scores increased by 2.5 points on average, and KCCQ-PL scores by 4 points through 12 weeks.
When categorized by 25-point ranges, the step count increased with increasing scores for both KCCQ-TS and KCCQ-PL. Those with KCCQ-TS scores of 0-24 averaged 2,437.6 steps daily, and those with scores of 75-100 averaged 4,870.9 steps daily.
Similarly, participants with KCCQ-PL scores of 0-24 averaged 2301.5 steps daily, and those with scores of 75-100 averaged 5,351.9. The relationship remained significant after adjustment.
There were nonlinear relationships between activity and KCCQ scores: Daily step counts below 5,000 steps were associated with KCCQ scores, but there was little association with counts above 5,000 steps.
Compared with participants who walked 2,000 steps per day, those who walked 1,000 had KCCQ-TS scores that were 3.11 points lower; participants who walked 3,000 had KCCQ-TS scores that were 2.89 points higher.
Similarly, participants who walked 1,000 steps per day had KCCQ-PL scores that were 5.36 points lower than those who walked 2,000 steps, and those who walked 3,000 steps had KCCQ-PL scores that were 4.97 points higher.
After adjustment, change in daily step counts was significantly associated with a change in KCCQ-PL scores from baseline through 12 weeks; for example, participants whose step counts increased by 2,000 steps per day experienced a 5.33 increase in their KCCQ-PL scores relative to participants whose step counts did not change.