Health related quality of life and mental distress after PCI: restoring a state of equilibrium

BACKGROUND: Patient self reported measures for Health Related Quality of Life (HRQOL) and mental distress are frequently used to evaluate outcome of therapeutic strategies in cardiac patients. Our study aims to describe changes in HRQOL and mental distress after percutaneous coronary intervention (PCI) focusing on temporal pattern of change and interdependences between both outcome measures. METHOD: 163 PCI patients recruited at 7 cardiovascular care units in Austria answered MacNew Health Related Quality of Life and Hospital Anxiety and Depression Scale (HADS) questionnaires during hospital stay after intervention and at 1, 6, 12 and 24 months. RESULTS: Improvement of MacNew HRQOL was found up to 6 month after PCI. Mental distress declined during the first month of the follow-up period. MacNew HRQOL is negatively correlated to mental distress. The relationship could be well described by a linear regression with MacNew HRQOL as dependent and HADS Total score as independent variable. The explained variance (R(2)) of the regression equation increases drastically from 45% at the baseline to a level between 67% and 77% in the follow up. CONCLUSION: Our data suggest that the regression equation describing the relation between MacNew HRQOL and HADS-Total score six month after PCI defines a state of equilibrium: In absence of actual symptoms of coronary artery disease (CAD) both measures reflect the general health status and the general attitude underlying the self-assessment of health. At the baseline this equilibrium is imbalanced because the symptoms of CAD have a more pronounced impact on the disease specific MacNew HRQOL measure than on the non-disease specific HADS measure for mental distress. In order to use the MacNew questionnaire as a monitoring and/or prognostic tool it seems promising to refer to the state of equilibrium to define expectancy values for successful treatment.