Study Design and Randomization
MAY, RECRUITMENT, RECRUITMENT, BLIND
This study (registration number ISRCTN61225589) was a cluster randomized trial. Recruitment and data collection were conducted between September 2015 and May 2017 at the Finnish Rehabilitation Center. This study was a real-life research project with a 1-year data recruitment period.Rehabilitees were distributed into 6 groups by officers of the Social Insurance Institution of Finland. Randomization occurred at the group level in pairs of 2 consecutive groups with following two experimental arms: (1) conventional cardiac rehabilitation with remote technology (remote technology intervention) group and (2) conventional cardiac rehabilitation (reference) group. The rehabilitees were randomized into 3 remote technology intervention clusters and 3 reference clusters. Rehabilitees were cluster randomized into cluster pairs, which bypassed any systematic bias that occurred because of the season. The clusters began in autumn (September to November), winter (December to February), and spring (March to May). The other cluster randomization–specific confounding factors, such as department and caregiver factors, were controlled in the study design using the same rehabilitation center and caregivers in all remote technology interventions (n=3) and reference groups (n=3).Randomization was accomplished with sealed envelopes within rehabilitation groups, and a person outside the research group (researcher of the gerontological research center) processed the randomization under the supervision of 2 researchers (TS and Heikki Kivistö). Randomization was performed 3 times for 2 consecutive groups, considering the season and months. In total, 59 rehabilitees were randomly assigned in pairs into (1) the remote technology intervention group (n=29) or (2) the reference group (n=30) in consecutive order. At the beginning of the rehabilitation, the researchers (TS and HK) informed the rehabilitees about the group (n=6) their rehabilitation group had been randomized. After randomization, rehabilitees provided written consent for their participation in the intervention. Because of the nature of the intervention, it was not possible to blind the rehabilitees and caregivers in terms of the intervention. The outcome assessor was not blinded to the intervention, but one educated person who was not involved in the study group performed the anthropometric measurements, and another person performed the 6-minute walk tests (6MWTs). The statistician was blinded to the interventions.Cardiac rehabilitation was implemented in groups of rehabilitees. The rehabilitees attended 3 sessions during the 5-day in-rehabilitation period in the rehabilitation center. Between these rehabilitation periods, there were two 6-month self-rehabilitation phases. All outcome measurements were performed at baseline and at the 6- and 12-month follow-ups (The design of the cardiac rehabilitation study.