What is the effect of a decision aid on knowledge, values and preferences for lung cancer screening? An online pre–post study

OBJECTIVE: To examine if a decision aid improves knowledge of lung cancer screening benefits and harms and which benefits and harms are most valued. DESIGN: Pre–post study. SETTING: Online. PARTICIPANTS: 219 current or former (quit within the previous 15 years) smokers ages 55–80 with at least 30 pack-years of smoking. INTERVENTION: Lung cancer screening video decision aid. MAIN MEASURES: Screening knowledge tested by 10 pre–post questions and value of benefits and harms (reducing chance of death from lung cancer, risk of being diagnosed, false positives, biopsies, complications of biopsies and out-of-pocket costs) assessed through rating (1–5 scale) and ranking (top three ranked). RESULTS: Mean age was 64.7±6.1, 42.5% were male, 75.4% white, 48.4% married, 28.9% with less than a college degree and 67.6% with income <US$50 000. Knowledge improved postdecision aid (pre 2.8±1.8 vs post 5.8±2.3, diff +3.0, 95% CI 2.7 to 3.3; p<0.001). For values, reducing the chance of death from lung cancer was rated and ranked highest overall (rating 4.3±1.0; 59.4% ranked first). Among harms, avoiding complications (3.7±1.3) and out-of-pocket costs (3.7±1.2) rated highest. Thirty-four per cent ranked one of four harms highest: avoiding costs 13.2%, false positives 7.3%, biopsies 7.3%, complications 5.9%. Screening intent was balanced (1–4 scale; 1-not likely 21.0%, 4-very likely 26.9%). Those ‘not likely’ to screen had greater improvement in pre–post knowledge scores and more frequently ranked a harm first than those ‘very likely’ to screen (pre–post diff:+3.5 vs +2.6, diff +0.9; 95% CI 0.1 to 1.8; p=0.023; one of four harms ranked first: 28.4% vs 11.3%, p<0.001). CONCLUSIONS: Our decision aid increased lung cancer screening knowledge among a diverse sample of screen-eligible respondents. Although a majority valued ‘reducing the chance of death from lung cancer’ highest, a substantial proportion identified harms as most important. Knowledge improvement and ranking harms highest were associated with lower intention to screen.