Statistical analysis

The primary aim of the PromMera study was to evaluate the effect of the smartphone application on physical activity. A sample size of 140 patients was determined sufficient to evaluate the primary end point. An additional power calculation demonstrated that a total of 110 patients (55 in each group) would provide 80% power to detect a 10% superiority in adherence rate in the intervention group (e.g., 60% vs. 50%) at a 5% significance level, assuming a standard deviation (SD) of 20% in both groups.

Analyses were performed according to intention‐to‐treat principles. Statistical analyses were performed with SPSS Statistics for Windows, version 25.0. (released 2017; IBM Corp., Armonk, New York). A t test was used to compare groups. A one‐tailed t test was used to compare adherence rates measured with pharmacy refill data and MARS‐5. A two‐tailed Fisher exact test was used to compare categorical variables. A p value <0.05 was considered statistically significant.

The trial was approved by the Swedish Ethical Review Authority (2016/1259‐31/4; 2017/1406‐32; 2017/2101‐32) and registered at www.ClinicalTrials.gov ({"type":"clinical-trial","attrs":{"text":"NCT03480464","term_id":"NCT03480464"}}NCT03480464). Informed consent was obtained from all participants.