Assessing a tool to measure patient functional ability after outpatient surgery

The '24-Hour Functional Ability Questionnaire' (24hFAQ) was developed to measure final recovery and satisfaction 24 h after surgery. We used structured interviews preoperatively to measure baseline patient concerns, and up to 24 h after discharge, to assess patient function and satisfaction. The primary objective was to assess the validity of the newly developed 24hFAQ in the postoperative outpatient setting. The criteria assessed were 1) Content: comparison with expert opinion and patients' views and response frequency distributions for asymptotes and irrelevance, 2) Construct: contribution of cognitive, physical, and satisfaction domains to postoperative functional ability, 3) Discrimination: comparing mean clinical end points with patient satisfaction, and 4) Criterion (predictive) validity: testing that related constructs are best correlated. Content validity was supported by the appropriate frequency distribution of subject responses, by the lack of floor or ceiling effects, and by <2% of responses indicating irrelevance. Construct validity was supported by moderate-to-strong positive interitem correlations within the cognitive and physical domains as predicted a priori. Discriminant validity support was mixed: key symptoms were associated with adverse patient satisfaction, but operating room and postanesthesia care unit residence times were unrelated. Criterion validity was supported by the finding that preoperative concern with key symptoms was independent of postoperafive outcomes. The validity assessment presented was the first assessment of the measurement capability of the 24hFAQ in an outpatient postoperative population. These results provide overall support for the validity of the 24hFAQ for use in outpatient populations.