Background: The Secondary Prevention in Uppsala Primary Healthcare Project (SUPRIM) is a prospective randomized controlled trial of a group-based cognitive behavioral therapy (CBT) stress management program for coronary heart disease (CHD) patients. The intervention reduced the risk of fatal or non-fatal first recurrent cardiovascular (CV) events. The aim of the present study was to analyze if the positive effects of the CBT program on clinical outcomes could have been mediated by changes in biomarkers for inflammation.
Methods: Altogether 362 patients with CHD were randomly assigned to intervention or usual care. The inflammatory biomarkers (VCAM-1, TNF-R1, TNF-R2, PTX3, and hs-CRP) were serially assessed at five time points every six months from study start until 24 months later, and analyzed with linear mixed models.
Results: Baseline levels of the inflammatory markers were near normal, indicating a stable phase. The group-based CBT stress management program did not significantly affect the levels of inflammatory biomarkers in patients with CHD. Three out of five (VCAM-1, TNF-R2, and PTX3) inflammatory biomarkers showed a slight increase over time in both study groups, and all were positively associated with age.
Conclusion: Group-based CBT stress management did not affect biomarkers for inflammation in patients with CHD. It is therefore unlikely that inflammatory processes including these biomarkers were mediating the effect the CBT program had on the reduction in CV events. The close to normal baseline levels of the biomarkers and the lack of elevated psychological distress symptoms indicate a possible floor effect which may have influenced the results.
Keywords: Biomarkers; CBT; CHD; inflammation; stress management.