OBJECTIVES: The phenomena of response-shift has recently entered the PRO literature and provided new insight how change scores in PRO measures such as HRQL-instruments can be interpreted. Methods have been provided to investigate the 3 types of response-shift: recalibration, reconceptualization and reprioritization. The aim of this study was to investigate to what extend response-shift occurs in individualized vs. disease-specific HRQL-instruments and how it can be captured. METHODS: In a prospective longitudinal study 100 patients with angiographically documented coronary artery disease were approached at 2 time points (hospital-baseline and 6 month-follow-up) with an individualized QoL-instrument (Schedule for the Evaluation of Individualized Quality of Life; SEIQOL) and a disease-specific HRQL-instrument (MacNew Heart Disease Quality of Life Questionnaire; MacNew). The SEIQoL is constructed allowing capturing two aspects of response-shift: reconceptualization (cues) and reprioritization (weights). In addition the “Then-Test” was applied to the MacNew at 6 month-follow-up to capture recalibration. RESULTS: Informed consent was given by 64 patients (61+/-7.5 years, 28.1% female, main symptom: 71.9% angina) and all patients were treated with percutaneous coronary interventions. 71.9% returned the six-month follow-up. Individualized QoL (SEIQoL-Index) did not improve over the 6 month-period (t0: 65.8+/-25.5; t1: 67.8+/-20.5, p=ns), in addition 25% of the participants showed response-shift effects of reconceptualization in at least one cue of the SEIQoL. No significant change in SEIQoL cue-weights occurred. Disease-specific HRQL scores changed significantly over time (t0: 4.7+/-1.2, t1: 5.3+/-1.1, p=0.004;) and no recalibration occurred (t0-then-test: 4.6+/-1.4, p=.418). CONCLUSION: This prospective study investigating the effects of percutaneous coronary interventions highlighted that response-shift effects may be a result of the instruments used. Individualized (generic) QoL -instruments can be prone to response-shift effects due to their conceptualization addressing a broad range of life aspects. In contrast, disease-specific PRO measures focusing on specific aspects of disease are less affected by response-shift phenomena.