Randomized controlled trial of mammography intervention in insured very low-income women.

Background: The expectation that insurance coverage mitigates health disparities and equalizes use of healthcare assumes that services are equally accessed; however, the insured low-income target population in this research had a mammography rate of 23.4%, well below the general population. Our objective was to determine the most effective intervention to improve mammography use in low-income women insured by a managed care organization (MCO).

Methods: The study was a randomized controlled trial. Participants were 2,357 women noncompliant with screening mammography randomly assigned to one of three groups: control (n = 786) received usual care; simple intervention (n = 785) received prompt letter from the MCO medical director; and stepwise intervention (n = 786) received the same prompt letter from the MCO; if noncompliant, a second prompt letter from their primary care physician and, if still noncompliant, counseling from lay health workers. Outcome was completion of screening mammography extracted from medical records.

Results: Screening rates were 13.4% for the control, 16.1% for the simple intervention, and 27.1% for the stepwise intervention. Compared with the control, the primary care physician letter in the stepwise intervention increased the likelihood of screening by 80% [Relative Risk (RR) = 1.80; P < 0.001], and counseling tripled the likelihood of screening (RR = 3.11; P < 0.001).

Conclusions: Compared with the control and simple intervention, a stepwise intervention to increase mammography is effective in a target population of hard-to-reach, low-income, insured women.

Impact: The research provides evidence for the impact of stepwise interventions to improve cancer screening in low-income insured populations, although the screening rates remain well below those of the general population.