Homelessness, Patient Navigation, and Lung Cancer Screening in a Health Center Setting: A Subgroup Analysis of a Randomized Clinical Trial.

Importance: Lung cancer is a major cause of death among people who experience homelessness. Patient navigation is an effective strategy for promoting lung cancer screening (LCS) in Health Care for the Homeless (HCH) settings, but little is known about whether the impact of this intervention differs for patients currently vs formerly experiencing homelessness. Objectives: To examine the effect of LCS patient navigation on individuals currently vs formerly experiencing homelessness, and to explore how navigation process measures differ for these subgroups. Design, Setting, and Participants: This is a subgroup analysis of the Investigating Navigation to Help Advance Lung Equity (INHALE) pragmatic randomized clinical trial of LCS patient navigation. The INHALE trial was conducted at Boston Health Care for the Homeless Program (BHCHP), a federally qualified health center serving nearly 10 000 patients who have experienced homelessness annually. The study included BHCHP primary care patients with a lifetime history of homelessness who were proficient in English and eligible for LCS under pre-2022 Medicare coverage criteria. The study was conducted between November 20, 2020, and March 29, 2023. Exposure: Current vs former homelessness, defined by self-reported responses to a detailed residential inventory. Sensitivity analyses further categorized individuals who formerly experienced homelessness as having stable or unstable housing. Main Outcomes and Measures: The primary outcome was verified receipt of a 1-time LCS low-dose computed tomography (LDCT) scan within 6 months after randomization. The risk difference (RD) in primary outcome attainment between navigation and usual care within each homelessness subgroup was calculated, and these RDs were compared by testing the interaction between study group and homelessness status in a linear binomial regression model with the identity link. Results: This study included 260 participants (mean [SD] age, 60.5 [4.7] years; 184 male individuals [70.8%]). At baseline, 84 patients (32.3%) were currently experiencing homelessness and 176 (67.7%) had formerly experienced homelessness. Patient navigation significantly increased LCS LDCT completion among both those currently (15 of 56 [26.8%] vs 2 of 28 [7.1%]; P = .04) and formerly (60 of 117 [51.3%] vs 6 of 59 [10.2%]; P < .001) experiencing homelessness. However, the treatment effect was significantly smaller among participants currently experiencing homelessness (RD, 19.7% vs 41.1%; P = .03), such that a disparity in LCS completion between these subgroups emerged under the navigation condition. Navigation process measures highlighted communication challenges with participants currently experiencing homelessness. In sensitivity analyses, LCS LDCT completion rates and navigation process measures were generally similar for stably vs unstably housed participants who formerly experienced homelessness. Conclusions and Relevance: In this subgroup analysis of a randomized clinical trial, patient navigation increased LCS participation among both patients currently and formerly experiencing homelessness; however, the effect size was smaller for those currently experiencing homelessness. Further improving cancer outcomes among HCH patients may require refinement of the patient navigation intervention, coupled with policy efforts to promote housing attainment among people experiencing homelessness. Trial Registration: ClinicalTrials.gov Identifier: NCT04308226.