Validation of an instrument to measure the impact of coronary disease on patient’s daily life

Aim. To evaluate the psychometric Instrument to Measure the Impact of Coronary Disease on Patient’s Everyday Life (IDCV) when applied on patients with coronary disease being followed at an outpatient clinic. Methods. One hundred and fifty‐three patients with coronary disease were registered. Patients were analysed in terms of acceptability, ceiling and floor effect, reliability (using Cronbach’s alpha coefficient) and convergent construct validity (by means of Spearman correlation) between the domains of IDCV and of ‘Medical Outcomes Trust Short‐form Health Survey (SF‐36)’ and ‘MacNew Heart Disease Health‐related Quality of Life Questionnaire’. Results. Evidence was found for high acceptability of IDCV. No evidence was found for ceiling and floor effects regarding the total score of IDCV; however, ceiling and floor effects were found from the adjustment to the disease domain. Evidence was found for reliability of the instrument as a whole and for its domains (Cronbach’s α ranged between 0·70–0·85). Similar domains on the IDCV, MacNew and SF‐36 were correlated: Physical impact – symptoms on the IDCV with the physical function domain on MacNew (r = −0·64) and with most domains on the SF‐36 related to the physical dimension; Social impact and emotional impact on the IDCV with emotional function (r = −0·53) and social function (r = −0·55) on the MacNew and mental health on SF‐36 (r = −0·55). However, smaller correlations of moderate/high magnitude were found between different constructs entre: Social and emotional impact on the IDCV with physical function on the MacNew (r = −0·56) and with the following domains: Functional capacity (r = −0·50), general health (r = −0·52) and vitality (r = −0·50) on SF‐36. Conclusion. The IDCV is an instrument with evidence regarding reliability and convergent validity also for the population of patients with coronary disease. Further studies to validate its factor structure could offer contributions for understanding the psychometric performance of the IDCV among patients with coronary disease.