Reliability and validity of the Patient Benefit Assessment Scale for Hospitalised Older Patients (P-BAS HOP).

Background: The Patient Benefit Assessment Scale for Hospitalised Older Patients (P-BAS HOP) is a tool which is capable of both identifying the priorities of the individual patient and measuring the outcomes relevant to him/her, resulting in a Patient Benefit Index (PBI) with range 0-3, indicating how much benefit the patient had experienced from the admission. The aim of this study was to evaluate the reliability, validity, responsiveness and interpretability of the P-BAS HOP.

Methods: A longitudinal study among hospitalised older patients with a baseline interview during hospitalisation and a follow-up by telephone 3 months after discharge. Test-retest reliability of the baseline and follow-up questionnaire were tested. Percentage of agreement, Cohen's kappa with quadratic weighting and maximum attainable kappa were calculated per item. The PBI was calculated for both test and retest of baseline and follow-up and compared with Intraclass Correlation Coefficient (ICC). Construct validity was tested by evaluating pre-defined hypotheses comparing the priority of goals with experienced symptoms or limitations at admission and the achievement of goals with progression or deterioration of other constructs. Responsiveness was evaluated by correlating the PBI with the anchor question 'How much did you benefit from the admission?'. This question was also used to evaluate the interpretability of the PBI with the visual anchor-based minimal important change distribution method.

Results: Reliability was tested with 53 participants at baseline and 72 at follow-up. Mean weighted kappa of the baseline items was 0.38. ICC between PBI of the test and retest was 0.77. Mean weighted kappa of the follow-up items was 0.51. ICC between PBI of the test and retest was 0.62. For the construct validity, tested in 451 participants, all baseline hypotheses were confirmed. From the follow-up hypotheses, tested in 344 participants, five of seven were confirmed. The Spearman's correlation coefficient between the PBI and the anchor question was 0.51. The optimal cut-off point was 0.7 for 'no important benefit' and 1.4 points for 'important benefit' on the PBI.

Conclusions: Although the concept seems promising, the reliability and validity of the P-BAS HOP appeared to be not yet satisfactory. We therefore recommend adapting the P-BAS HOP.