Development and validation of knowledge, attitude and practice questionnaire for patients with age- related macular degeneration

Abstract

Age-related macular degeneration (AMD) is the leading cause of visual impairment and severe vision loss in developed countries. There is a lack of validated instrument to measure knowledge, attitude, and practice (KAP) in AMD patients. The aim of this study was to develop and validate a questionnaire to evaluate KAP of patients with AMD, to determine the level of KAP and to investigate the role of contributing factors in predicting KAP levels among patients with AMD. The questionnaire was developed following a standardized protocol that consisted of literature review, expert opinion, and focus group discussion. Cognitive interviews were conducted among 12 patients diagnosed with AMD to determine face validity. Construct validity and reliability of the questionnaire were measured by which the questionnaire was administered to a total of 120 patients diagnosed with AMD. Level of KAP were determined using mean and standard deviation and further categorized using Blooms cut-off point. Pearson’s Chisquare and logistics regression was used to identify the factors that affected KAP of AMD. Content validity index and modified kappa showed excellent values for most items in the knowledge domain. The Kaiser-Meyer- Olkin sampling adequacy (KMO) showed acceptable scores of 0.70 and 0.75 for both attitude and practice domains respectively and Bartlett’s Test of Sphericity were significant (χ2= 0.00, P <0.001). The Cronbach’s alpha showed acceptable values for all items with values >0.70 with good test-retest reliability. The final version of the questionnaire consisted of 93-items. Overall, the patients scores were low for knowledge (45.8%), moderate for both attitude (79.2%) and practice (56.7%). Gender and level of education showed significant association with high knowledge score (p<0.2). This study showed that males were less likely to have higher knowledge scores than females (AOR: 0.187, CI :0.044 – 0.800). The participants with secondary education were less likely to have higher knowledge score as compared to those with tertiary education (AOR:0.121, CI :0.020 - 0.743). There were no significant association between high attitude scores with independent variables, gender, education level, duration of disease, and household income. For moderate practice score, gender and level of education also showed significant association (p<0.2). It was shown that male gender were two times more likely to have moderate practice score as compared to the female gender (AOR: 3.096, CI: 1.163- 8.242). Those patients with none /primary education level of education were less likely to have moderate practice score as those with tertiary education (AOR: 0.283, CI :0.087 – 0.916). In conclusion, a reliable and valid instrument to measure KAP has been developed for patient’s diagnosed with AMD. The information gathered through the instrument can be used as baseline for specific intervention in future studies.