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

## TL;DR

Patient navigation helps increase lung cancer screening among homeless and formerly homeless patients, but it's less effective for those currently homeless due to communication barriers.

## Contribution

This study is the first to compare the effectiveness of patient navigation for lung cancer screening between currently and formerly homeless individuals.

## Key findings

- Patient navigation increased screening completion by 20% for currently homeless and 41% for formerly homeless participants.
- The effect of navigation was significantly smaller for currently homeless individuals, highlighting communication barriers.
- Formerly homeless participants with stable or unstable housing had similar screening outcomes under navigation.

## Abstract

Does the effect of patient navigation on lung cancer screening completion differ for patients currently vs formerly experiencing homelessness?

In this subgroup analysis of a randomized clinical trial involving 260 participants, patient navigation significantly improved lung cancer screening completion among both those currently (20% absolute increase) and formerly (41% absolute increase) experiencing homelessness, but the effect size was significantly smaller for those currently experiencing homelessness. Communication barriers likely underpinned this differential effect.

These findings suggest that optimizing screening participation among patients who have experienced homelessness may require further tailoring of the navigation intervention and policy efforts to promote housing for people who are currently experiencing homelessness.

This subgroup analysis of a randomized clinical trial examines differences in the effects of patient navigation for lung cancer screening among individuals currently or formerly experiencing homelessness.

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.

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.

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.

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.

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.

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.

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.

ClinicalTrials.gov Identifier: NCT04308226