Predictors of participant nonadherence in lung cancer screening programs: a systematic review and meta-analysis

The low nonadherence rates reported by large low-dose computed tomography (LDCT) lung cancer screening trials were not necessarily replicated outside of trial conditions. This systematic review and meta-analysis identified predictors of participant nonadherence to returning for annual LDCT screening. The systematic review protocol was registered at PROSPERO (CRD42019118347). MEDLINE, EMBASE, CINAHL, AgeLine, grey literature sources, and reference lists of included studies were searched until March 1st, 2020. Primary research articles were eligible for inclusion if they screened current or former smokers using LDCT as their primary screening modality and reported on participant demographics or programmatic interventions that predicted nonadherence. Risk of bias assessment was performed at both study and outcome levels. The primary outcome was predictors of nonadherence. The secondary outcomes were relative risks (RR) of second round nonadherence based on identified predictors, which were calculated using random-effects meta-analyses. Across 13 included studies (total n = 15,790; range: 157-3642), the overall rate of nonadherence was 28% (95% CI: 20-37%). Studies identified greater nonadherence in participants younger than 60 or older than 74, with longer travel distances to screening centers, and having a low risk perception of lung cancer. Meta-analyses identified higher nonadherence in community-based compared to academic-based programs, but this did not reach significance (32% versus 27%; p = 0.32). Current smokers were more likely to be nonadherent compared to former smokers (RR 1.23, 95% CI: 1.09-1.40; p < 0.01) while white participants were less likely nonadherent compared to non-white participants (RR 0.69, 95% CI: 0.60-0.81; p < 0.0001). No differences existed between male and female participants (RR 0.99, 95% CI: 0.85-1.15; p = 0.85). Programmatic interventions, including dedicated program coordinators, reminder calls/letters, and mobile LDCT scanners reduced nonadherence in lung cancer screening programs. These interventions should be targeted/tailored toward the subpopulations with the highest nonadherence rates.