The validity, reliability, sensitivity and responsiveness of a modified Patient Enablement Instrument (PEI-2) as a tool for serial measurements of health enablement

BACKGROUND: Patient enablement is a core tenet of patient-centred and holistic primary care. The Patient Enablement Instrument (PEI) is a transitional measure limited in its ability to measure changes over time. A modified version, PEI-2, has been developed to measure enablement at a given time-point without comparison to a recalled baseline. OBJECTIVE: To assess the validity, reliability, sensitivity and responsiveness of PEI-2. METHODS: PEI-2 was modified from the Chinese PEI to assess enablement over 4 weeks in a prospective cohort study nested within a community support programme [Trekkers Family Enhancement Scheme (TFES)] in Hong Kong. Construct validity was assessed by factor analysis and convergent validity by Spearman’s correlations with health-related quality of life and depressive symptoms. Internal reliability was assessed using Cronbach’s alpha. Test–retest reliability was assessed by intraclass correlation (ICC), responsiveness by 12–24-month change in PEI-2 score and sensitivity by differences in change of PEI-2 score between TFES participants and a control group. RESULTS: PEI-2 demonstrated construct validity with all items loading on one factor (factor loadings >0.7). Convergent validity was confirmed by significant correlations with 12-item Short Form Questionnaire, version 2 (r = 0.1089–0.1919) and Patient Health Questionnaire-9 (r = −0.2030). Internal reliability was high (Cronbach’s alpha = 0.9095) and test–retest reliability moderate (ICC = 0.520, P = 0.506). Significant improvements in PEI-2 scores among the TFES group suggested good responsiveness (P < 0.001). The difference in change of PEI-2 scores between TFES and control was significant (P = 0.008), indicating good sensitivity. CONCLUSIONS: This study supports the validity, reliability, sensitivity and responsiveness of PEI-2 in measuring changes in enablement, making it a promising tool for evaluating enablement in cohort and intervention studies.