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

Abstract

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.

Keywords: general medicine (see internal medicine); oncology; preventive medicine; primary care.