Evaluation of the functional status questionnaire in heart failure: a sub-study of the second cardiac insufficiency bisoprolol survival study (CIBIS-II)

We evaluated a generic quality of life (QoL) Functional Status Questionnaire (FSQ), in patients with chronic heart failure (CHF). The FSQ assesses the 3 main dimensions of QoL: physical functioning, mental health and social role. It also includes 6 single item questions about: work status, frequency of social interactions, satisfaction with sexual relationships, days in bed, days with restricted activity and overall satisfaction with health status. The FSQ was compared to the Minnesota Living with Heart Failure questionnaire (MLwHF).

The FSQ was evaluated in a substudy (n = 340) of the second Cardiac Insufficiency Bisoprolol Survival study (CIBIS-II), a placebo-controlled mortality trial. 265 patients (75%) patients completed both questionnaires at 6 months of follow-up. Both questionnaires indicated substantially impaired QoL. The FSQ demonstrated high internal consistency (Cronbach's α > 0.7 for all items except "social activity" = 0.66) and construct and concurrent validity. After 6 months, the only item on either questionnaire to show a difference between the placebo- and bisoprolol-treatment groups was the single item FSQ question about "days in bed" (p = 0.018 in favour of bisoprolol).

The FSQ performed well in this study, provided additional information to the MLwHF questionnaire and allowed interesting comparisons with other chronic medical conditions. The FSQ may be a useful general QoL instrument for studies in CHF.