Category: Health Psychology / Behavioral Medicine - Adult
Cardiac rehabilitation (CR) is a comprehensive exercise, education, counseling and behavior modification program designed to improve patient health and quality of life following a significant cardiovascular event. Active and regular participation in CR is essential to realize the physical and mental health benefits. Non-adherence and low attendance are significant barriers for patients. In fact, dropout rates have been shown to be as high as 50%, with psychosocial variables significantly influencing pre-mature termination (McGrady et al., 2009). A brief psychosocial intervention was developed and improved compliance and retention (McGrady et al., 2014), yet a determination on the adequate dose of the intervention remains unknown.
The present study examined the dose effect of a 4-session motivational interviewing and stress management intervention on patient retention and adherence to a 36-session cardiac rehabilitation program. Discriminant function analysis was utilized to determine if the number of intervention sessions could adequately predict group membership of a) completers of cardiac rehabilitation and b) dropouts due to non-compliance. It was expected that a higher dose of brief psychosocial intervention would predict group membership.
Patients were recruited from an AACVPR-accredited Phase II cardiac rehabilitation program at a large academic medical center. Patients were randomized to a four- session intervention or treatment as usual. The intervention consisted of group therapy with two treatment components: motivational interviewing and stress management. 52 patients were randomized to the intervention condition. 47 patients were retained for analysis. 32 patients completed CR, and 15 dropped out due to non-compliance. First, a discriminant function analysis was completed to test the primary hypothesis; number of intervention sessions (1-4 sessions) was entered as the IV and cardiac rehab completion vs. dropout as a categorical DV. The discriminant function analysis explained 27% of variance (canonical R2 = 0.26). The number of intervention sessions significantly differentiated CR completers vs. dropouts, [Λ = 0.726, χ² (1) = 14.261, P > 0.001]. The model correctly classified more than 84% of the cases. Second, a post-hoc discriminant function analysis was conducted to determine if commonly used predictors of CR outcome could better determine CR completion vs. dropout membership. Pretreatment BDI, BAI, and walk test score were entered as IVs. This analysis explained only 10% of variance (canonical R2 = .315). Pre-treatment depression, anxiety, and walk test results only marginally significantly differentiated CR completers vs. dropouts [Λ = 0.901, χ² (3) = 7.803, P = 0.05].
Results suggest a dose effect of psychosocial intervention aimed at improving CR completion. With dropout rates reaching close to 50% (McGrady et al., 2009) adjunct interventions have been proven effective at reducing this number (McGrady et al., 2014), and the current study suggests that receiving more sessions of psychosocial intervention may be advantageous. The authors will discuss the findings in the broader context of the dose-effect in psychotherapy and with medical patients.
Jason Levine– University of Toledo, Toledo, Ohio
Angele McGrady– University of Toledo
Rachel Sieke– University of Toledo
Alex Buhk– Doctoral Candidate, University of TOledo
Joanna Hayward– Doctoral Candidate, University of Toledo, Timonium, Maryland
Dalynn Badenhop– University of Toledo