Validation of the Knowledge of Genome Sequencing (KOGS) scale in cancer patients

Abstract

IntroductionThe Knowledge of Genome Sequencing (KOGS) questionnaire was recently developed to measure knowledge of genomic sequencing (GS), with preliminary psychometric data supporting its reliability and validity. The aim of this study was to test the reliability and validity of the KOGS in a larger sample, and to confirm its utility in a cancer setting. MethodsThe Genetic Cancer Risk in the Young (RisC) study recruits participants with a personal history of cancer, to investigate heritable cancer causes and future cancer risk using germline GS. Participants (n = 261) in a psychosocial substudy of RisC completed a questionnaire after consent to RisC but before GS, including the KOGS, the Intolerance of Uncertainty Scale, the Chew health literacy scale and items assessing demographic and disease variables. Confirmatory factor analysis (CFA), Cronbach alpha and correlational analyses were undertaken. ResultsThe CFA testing a single-factor model yielded a good model fit, χ2/df = 2.43, comparative fit index (CFI) = 0.97, root mean square error of approximation (RMSEA) = 0.07 and weighted mean root square (WRMR) = 1.03. Factor loadings of all items were above 0.60 and ranged between.66 and.93. The single factor score demonstrated excellent internal consistency (α = 0.82). KOGS scores were significantly associated with health literacy (r = 0.23, p < .001), having a university education [t(258) = −4.53, p < .001] and having a medical or science background [t(259) = −3.52, p < .001] but not with speaking a language other than English at home, time since diagnosis, previous genetic counselling/testing or intolerance of uncertainty. DiscussionThis study confirmed a single-factor structure for the KOGS, and its reliability and validity in a cancer population. Associations with measures of health literacy and education were significant and positive as expected, supporting the KOG’s construct validity. Previous genetic counselling may not be sufficient to provide specific knowledge of GS.