A brief measure of Smokers' knowledge of lung cancer screening with low-dose computed tomography

Abstract

We describe the development and psychometric properties of a new, brief measure of smokers' knowledge of lung cancer screening with low-dose computed tomography (LDCT). Content experts identified key facts smokers should know in making an informed decision about lung cancer screening. Sample questions were drafted and iteratively refined based on feedback from content experts and cognitive testing with ten smokers. The resulting 16-item knowledge measure was completed by 108 heavy smokers in Houston, Texas, recruited from 12/2014 to 09/2015. Item difficulty, item discrimination, internal consistency and test-retest reliability were assessed. Group differences based upon education levels and smoking history were explored. Several items were dropped due to ceiling effects or overlapping constructs, resulting in a 12-item knowledge measure. Additional items with high item uncertainty were retained because of their importance in informed decision making about lung cancer screening. Internal consistency reliability of the final scale was acceptable (KR-20 = 0.66) and test-retest reliability of the overall scale was 0.84 (intraclass correlation). Knowledge scores differed across education levels (F = 3.36, p = 0.04), while no differences were observed between current and former smokers (F = 1.43, p = 0.24) or among participants who met or did not meet the 30-pack-year screening eligibility criterion (F = 0.57, p = 0.45). The new measure provides a brief, valid and reliable indicator of smokers' knowledge of key concepts central to making an informed decision about lung cancer screening with LDCT, and can be part of a broader assessment of the quality of smokers' decision making about lung cancer screening.

Responsiveness of a Brief Measure of Lung Cancer Screening Knowledge

“…Overall score improvement is consistent with previous work describing the importance of knowledge as an outcome measure for evaluating decision aids [13, 26]. We found total score as well as individual items, supporting reliability and validity of the measure [16, 18, 19].…”

“…While all items showed participant knowledge improvement, some were more responsive than others. Items with high baseline scores (e.g., item 8 on the mortality benefit of screening and item 10 on secondary findings) showed less improvement, but we suggest these items be retained because they reflect important concepts in making informed screening decisions about whether to get screened for lung cancer [16].…”

“…In prior work, we developed the LCS-12 based on a consensus process where key facts were identified as essential knowledge for making an informed decision about lung cancer screening. The 12-item measure showed good test-retest reliability (ICC=.84) and discrimination between high and low performers, although item difficulty was high for several items [16]. We retained several high difficulty items due to their coverage of key concepts in making informed screening decisions, such as positive predictive value of an abnormal screening result.…”

“…One concept supported by certification standards is knowledge, a necessary component of decision quality [8–13]. Previously, we developed a brief measure, the LCS-12, to characterize knowledge of lung cancer screening among smokers and former smokers and to serve as an outcome measure for studies evaluating shared decision making interventions[16]. The objective of this study is to examine the responsiveness of the LCS-12 to capture changes in patient’s knowledge after viewing a video-based patient decision aid about lung cancer screening.…”

Using Social Media as a Platform for Increasing Knowledge of Lung Cancer Screening in High-Risk Patients

“…The LCS-12 is a validated patient knowledge assessment tool that was developed specifically to assess change in knowledge after viewing a video-based decision aid about lung cancer screening ( Lowenstein et al, 2016 ). The LCS-12 contains 12 questions.…”