METHODS: Out of 105 patients with IHD, 76 completed self-administration of HeartQoL at the clinic followed by at home within a 2-week interval. In retest, patients responded using non-interview methods (phone messaging, email, fax, and post). Phone interviewing was reserved for non-respondents to reminder.
RESULTS: Reliability of HeartQoL was good (intraclass correlation coefficients = 0.78-0.82), was supported in the Bland-Altman plot, and was comparable to five studies on MacNew of similar retest interval (MacNew-English = 0.70-0.75; translated MacNew = 0.72-0.91). Applicability of its standard error of measurement (0.20-0.25) and smallest detectable change (0.55-0.70) will depend on availability of normative data in future.
CONCLUSION: The reliability of HeartQoL is comparable to its parent instrument, the MacNew. The HeartQoL is a potentially reliable core IHD-specific HRQoL instrument in measuring group change.