ABSTRACT
This manuscript describes the development and validation of measures assessing patient knowledge about the risks and benefits of prostate cancer (CaP) screening. The measures described include a 10-item knowledge index and four single-item measures, used in previous studies, that assess knowledge of: CaP natural history and treatment efficacy, expert disagreement over the value of CaP screening, and the accuracy of the prostate specific antigen (PSA) test for CaP. We assessed the validity and reliability of these measures on a sample of 1152 male veteran patients age 50 and older. All knowledge index items had acceptable levels of discrimination, difficulty, and reliability. The index demonstrated strong evidence for construct and criterion validity. Much weaker validity evidence was found for the four single-item knowledge questions. The 10-item index developed in this study provides a valid and reliable tool for assessing patient knowledge of the risks and benefits of CaP screening.
Subject(s)
Educational Measurement , Mass Screening , Patient Education as Topic , Prostatic Neoplasms/diagnosis , Surveys and Questionnaires/standards , Aged , Attitude to Health , Comorbidity , Discriminant Analysis , Educational Measurement/methods , Educational Measurement/standards , Health Knowledge, Attitudes, Practice , Humans , Male , Mass Screening/adverse effects , Mass Screening/psychology , Mass Screening/standards , Middle Aged , Midwestern United States , Patient Education as Topic/standards , Prostate-Specific Antigen/blood , Prostatic Neoplasms/epidemiology , Prostatic Neoplasms/therapy , Psychometrics , Risk Factors , Sensitivity and Specificity , Treatment Outcome , Veterans/educationABSTRACT
OBJECTIVE: To assess the effect of video and pamphlet interventions on patient prostate cancer (CaP) screening knowledge, decision-making participation, preferences, and behaviors. DESIGN: Randomized, controlled trial. SETTING: Four midwestern Veterans Affairs medical facilities. PATIENTS/PARTICIPANTS: One thousand, one hundred fifty-two male veterans age 50 and older with primary care appointments at participating facilities were randomized and 893 completed follow-up. INTERVENTIONS: Patients were randomized to mailed pamphlet, mailed video, or usual care/control. MEASUREMENTS AND MAIN RESULTS: Outcomes assessed by phone survey 2 weeks postintervention included a 10-item knowledge index; correct responses to questions on CaP natural history, treatment efficacy, the prostate-specific antigen (PSA)'s predictive value, and expert disagreement about the PSA; whether screening was discussed with provider; screening preferences; and PSA testing rates. Mean knowledge index scores were higher for video (7.44; P = .001) and pamphlet (7.26; P = .03) subjects versus controls (6.90). Video and pamphlet subjects reported significantly higher percentages of correct responses relative to controls to questions on CaP natural history (63%, 63%, and 54%, respectively); treatment efficacy (19%, 20%, and 5%), and expert disagreement (28%, 19%, and 8%), but not PSA accuracy (28%, 22%, and 22%). Pamphlet subjects were more likely than controls to discuss screening with their provider (41% vs 32%; P = .03) but video subjects were not (35%; P = .33). Video and pamphlet subjects were less likely to intend to have a PSA, relative to controls (63%, 65%, and 74%, respectively). PSA testing rates did not differ significantly across groups. CONCLUSIONS: Mailed interventions enhance patient knowledge and self-reported participation in decision making, and alter screening preferences. The pamphlet and video interventions evaluated are comparable in effectiveness. The lower-cost pamphlet approach is an attractive option for clinics with limited resources.
