Method
Study Sample
The study sample was drawn from the PRODES-Austria registry in which between January 1st, 2008 and December 31st, 2011 310 PCI patients form 7 centres in Austria aged between 18 and 80 years treated with a drug eluting Xience stent participated. Patients with acute ST-elevation myocardial infarction (STEMI) or stent deployment during the last 6 months were excluded from the registry. The PRODES-Austria registry was designed to analyse changes in Health related Quality of Life and Mental Distress after PCI over a 24 months follow-up period by a prospective, multi-centre approach. Clinical data were collected at hospital admission. The patients completed the baseline questionnaires (HADS and MacNew) during hospital stay after cardiovascular intervention. Follow-up questionnaires were answered at 1, 6, 12 and 24 months. The study was conducted in accordance to the Helsinki Declaration with approval by the local ethic commission. All participants provided written informed consent.
MacNew
The self-administered MacNew is designed to assess patient's perception about how CAD affects daily functioning and contains 27 items with a global HRQOL score and physical limitation, emotional, and social function subscales. Using a 2-week time frame, the MacNew items and subscales are scored from 1 (low HRQL) to 7 (high HRQL). To assess the impact of PCI on individual patients we refer to the minimal important difference (MID), the smallest change of a score patients perceive as important. For the MacNew Global score Dixon and colleagues have established a MID of 0.5 points. The German version of MacNew has been shown to be valid and reliable for ischemic heart disease.
HADS
The Hospital Anxiety and Depression Scale (HADS) is a validated psychological screening instrument widely used in CAD patients. The questionnaire includes 14 questions and results in separate scores for anxiety and depression. A recently published 10-year review questioned the ability of HADS to differentiate between anxiety and depression and recommended to use HADS scores more general as a measure for mental distress. A score for mental distress can be calculated by summing up depression and anxiety scores.
Statistical Analysis
Discrete variables were compared with chi-square test or Fisher Exact test when appropriate. Continuous variables were examined with t-test or Mann–Whitney-U-Test, changes of MacNew and HADS scores with Wilcoxon test. Linear regressions were calculated using the ordinary least square (OLS) method. All statistical analyses were performed with PASW Statistics 18.0 software with two-tailed p-values <0.05 considered statistically significant.