Smartphone app fails to boost MVPA in diabetics

Among patients with type 2 diabetes (T2D), use of the smartphone-based app InterWalk does not improve objective measures of moderate-to-vigorous physical activity (MVPA), according to a study.

After 52 weeks of intervention, MVPA changed slightly by –0.2 minutes per day (95 percent confidence interval [CI], –3.8 to 3.3; p=0.91) in the InterWalk group. Controls, who received the standard exercise program, saw an MVPA least squares mean of 0.6 minutes per day (95 percent CI, –4.6 to 5.8; p=0.81). The impact of the device-based exercise intervention was not statistically significant (mean difference, –0.8, 95 percent CI, –8.1 to 6.4; p=0.82). [JMIR Mhealth Uhealth 2022;10:e30602]

Nevertheless, the InterWalk intervention led to a significant increase in physical health-related quality of life, which increased by a mean of 4.3 (95 percent CI, 3.1–5.6) and 4.2 (95 percent CI, 3.0–5.4) points at 12 and 52 weeks, respectively, while scores remained mostly unchanged in controls. The resulting mean difference values were 3.7 (95 percent CI, 1.2–6.1) and 4.3 (95 percent CI, 1.8–6.9) points at 12 and 52 weeks, respectively.

Similarly, waist circumference decreased by 3.1 cm (95 percent CI, –4.0 to –2.2) after 52 weeks in patients who received the device-based exercise intervention. This reduction was greater by 2.3 cm (95 percent CI, –4.0 to 0.4) than in controls, though this effect was only of borderline significance (p=0.06).

InterWalk was unable to elicit significant improvements in other key secondary endpoints, including mental health-related quality of life, peak oxygen consumption, self-rated physical activity energy expenditure, relative autonomy index scores, and weight.

“The main finding of this study was that InterWalk app–based interval walk training (IWT) did not increase objectively measured MVPA time over 52 weeks compared with standard care among individuals with T2D referred to municipality-based lifestyle programs,” the researchers said.

Diabetes-specific exercise app

Developed in collaboration with and consideration of patients with T2D, InterWalk was designed to facilitate IWT through continuous and individualized audio feedback. Specifically, the app guides the user through cycles of slow and fast walking, with each phase lasting 3 minutes each.

In this study, patients underwent a 7-minute standard walking test at baseline and repeated every 4 weeks. The results of these test were used to individualize the device-based interval training regimen. An onboard accelerometer was used to identify individual walking intensity cut-offs for each patient. Audio prompts were given if participants were too far above or below their upper or lower limits.

At the end of each interval training session, smartphone devices would display relevant data including session duration, walking distance, number of steps taken, and the quality of their performance.

The InterWalk app also measured participant adherence to the regimen using the session’s intensity, duration, and frequency. These analyses showed that regimen adherence was low throughout 52 weeks of intervention, which could have explained the lack of effect on the primary outcome.

Of note, adherence was much better during the first 12 weeks of intervention, during which a notably higher but statistically nonsignificant effect on MVPA was observed among participants allocated to InterWalk.

“During the 12-week exercise program, IWT adherence was remarkably higher and MVPA time increased by >10 percent from baseline, indicating that InterWalk app–based IWT potentially contributed to increased MVPA time,” the researchers said.

Still, “InterWalk app–based IWT may not—in the present circumstances—be feasible for maintaining PA level after a municipality-based exercise program,” they added.