SCRAM did not lead to a clinically important difference in VO2max compared to usual cardiac care in this underpowered trial, but was resilient to COVID-19-related disruptions that significantly impacted the delivery of cardiac rehabilitation.
Key Findings
Results
The SCRAM intervention did not produce a statistically significant improvement in the primary outcome of maximal aerobic exercise capacity (VO2max) at 24 weeks compared to usual care.
Mean VO2max at 24 weeks was 26.10 (SD 10.72) mL/kg/min in the SCRAM group versus 24.65 (SD 7.87) mL/kg/min in the control group.
The mean difference was 1.61 mL/kg/min (95% CI -1.38 to 4.61, P=.28).
Analysis was intention-to-treat using linear regression adjusted for baseline and stratification factors on multiple imputed data.
The trial was underpowered, with only 123 of the required 220 participants (56%) recruited and randomized.
Results
Patients receiving SCRAM had significantly lower diastolic blood pressure at 24 weeks compared to control.
Mean difference in diastolic blood pressure was -5.54 mm Hg (95% CI -10.01 to -1.06) favoring the SCRAM intervention.
This was identified among secondary outcomes.
No other secondary outcomes were reported as statistically significant in the abstract.
Results
Recruitment and data collection were severely impacted by the COVID-19 pandemic, resulting in significant missing data for the primary outcome.
Only 123 of the 220 required participants (56%) were recruited and randomized (intervention n=63, control n=60).
45% (55/123) of participants had missing VO2max data at 24 weeks, largely due to enforced COVID-19 restrictions.
Recruitment and data collection took place from 2018 to 2021 at 3 hospitals in Victoria, Australia (Melbourne, Geelong, and Bendigo).
Usual cardiovascular care, which included referral to center-based cardiac rehabilitation, was heavily impacted during COVID-19, whereas SCRAM delivery was sustained throughout.
Discussion
SCRAM demonstrated resilience to COVID-19-related disruptions by sustaining delivery of remote cardiac rehabilitation throughout the pandemic.
SCRAM provided 24 weeks of remote exercise supervision, coaching, and behavior change support via smartphone.
Center-based cardiac rehabilitation and supervised exercise training were significantly disrupted by COVID-19.
The program was designed as a dual-phase telerehabilitation program to address accessibility barriers to center-based cardiac rehabilitation.
Results
Adverse events were reported more frequently in the intervention group than the control group, but all were deemed mild or moderate in severity.
Adverse events were reported in 16 intervention participants and 6 control participants.
Only one adverse event was deemed possibly related to treatment.
There were no deaths or hospitalizations reported.
Participants were clinically stable adults aged ≥18 years with diagnosed coronary heart disease.
Methods
The trial used a multicenter, parallel 2-arm randomized controlled trial design with stratified randomization but was not blinded to participants due to the nature of the treatments.
Randomization was 1:1, stratified by sex and study site.
Primary outcome assessors and biostatisticians were blinded to allocation.
Participants were not blinded to allocation due to the nature of the treatments.
Three hospital sites in Victoria, Australia were included: Melbourne, Geelong, and Bendigo.