Development and psychometric evaluation of the patient's HIV knowledge questionnaire (PHKQ)

Background Valid and reliable instruments for measuring knowledge about human immuno-deficiency virus (HIV) among people living with the virus are necessary to identify knowledge gaps and evaluate effectiveness or outcomes of education programmes. However such instruments are scarce, particularly in developing countries. Objective This study aimed to develop and validate a self-administered instrument for measuring HIV-related knowledge among people living with HIV in Nigeria. Setting This study was conducted in the HIV/AIDS clinic of the University of Uyo Teaching Hospital, Akwa Ibom State, Nigeria. Methods The Patient's HIV Knowledge Questionnaire (PHKQ) items, designed with response choices of 'yes', 'no' and 'don't know', were developed based on relevant literature and similar published studies. Face and content validity were established. Evidence of construct validity was established by factor analysis and group differences. Factor analysis was done using principal components and varimax rotation with Kaiser Normalization. Estimates of reliability were evaluated using internal consistency approach (with Cronbach's alpha coefficient) as well as the test-retest method for estimating the stability of the PHKQ scores over time (with Pearson's r). Main outcome measure Validity/reliability of the Patient's HIV Knowledge Questionnaire. Result Response rate in this study was 95.0%. Item analysis of the 20-item instrument resulted in the deletion of 5 items; thus the final instrument consists of 15 items. Cronbach's alpha coefficient for the scale was 0.77, while test-retest reliability was 0.80 (p < 0.001). Factor analysis resulted in 3 components-Transmission and Misconceptions, Causes and Treatment Outcomes, and Diet and Immunity-with Cronbach's alpha of 0.70, 0.56 and 0.46 respectively. The Patient's HIV Knowledge Questionnaire differentiated between newly diagnosed (≤ 1 year) individuals and those with at least 10 years since HIV diagnosis, and also between those with only primary education and those who had had up to tertiary education (p < 0.001). Conclusion The Patient's HIV Knowledge Questionnaire appears to be a valid and reliable tool for assessing HIV-related knowledge among people living with HIV in Nigeria. Further studies are needed to explore the instrument's responsiveness to change, and to evaluate its psychometrics in different settings.