Background: The Breast Screening and Patient Navigation (BSPAN) Program provides access to no-cost breast cancer screening services to uninsured women in North Texas. Using data from the longitudinal BSPAN program (2012–2019), we assessed prevalence and correlates of (i) baseline adherence and (ii) longitudinal adherence to screening mammograms.

Methods: Outcomes were baseline adherence (adherent if women received second mammogram 9–30 months after the index mammogram) and longitudinal adherence (assessed among baseline adherent women and defined as being adherent 39 months from the index mammogram). We used multivariable logistic regression and multivariable Cox proportional hazards model to assess associations of sociodemographic and clinical characteristics with baseline and longitudinal adherence, respectively.

Results: Of 19,292 women, only 5,382 (27.9%) were baseline adherent. Baseline adherence was more likely among women who were partnered, preferred speaking Spanish, had poor reading ability, had prior Papanicolaou (PAP) testing, and prior screening mammograms, compared with women who were non-partnered, preferred speaking English, had good reading ability, had no prior PAP testing, and no prior screening mammograms, respectively. Of those who were baseline adherent, 4,364 (81.1%) women demonstrated longitudinal adherence. Correlates of longitudinal adherence were similar to those from baseline adherence.

Conclusions: A large proportion of baseline adherent women (>80%) achieved longitudinal adherence, which highlights the importance of concentrating resources during the second mammogram in the progression toward continued adherence.

Impact: Results from our unique dataset provide realistic mammography adherence rates and may be generalizable to other areas introducing no-cost screening to low-income women, independent of any regular patient-centered medical home.