Effect of an Intervention in General Practice to Increase the Participation of Immigrants in Cervical Cancer Screening: A Cluster Randomized Clinical Trial.

Importance: Immigrant women have lower participation in cervical cancer screening (CCS) programs. At the same time, some groups of immigrants have higher prevalence of cervical cancer. Targeted interventions are therefore necessary. Objective: To determine whether an intervention among general practitioners (GPs) could influence immigrant women's participation in the Norwegian CCS program. Design, Setting, and Participants: Cluster-randomized clinical trial using the 20 subdistricts of the Bergen, Norway, municipality as clusters. The clusters were matched in 10 pairs according to the number of immigrant women living in them and randomized thereafter. The intervention was implemented between January and June 2017 among urban, primary care, general practices in Bergen. Follow-up ended in January 2018. General practices belonging to the control areas continued treatment as usual. A total of 10 360 women who attended 73 general practices in the 20 subdistricts were included as participants. Intervention: The intervention consisted of 3 elements: an educational session for GPs at lunch describing the importance of CCS among immigrants and giving advice about how to invite them to participate, a mouse pad as a reminder, and a poster placed in waiting rooms. In the educational session, we elaborated the need for GPs to ask every immigrant woman about CCS, regardless of their reason for contacting their GP. Main Outcomes and Measures: The main outcome, screening status of immigrant women by January 1, 2018, was obtained from the Norwegian Cancer Registry. The effect of the intervention was measured as odds ratio (OR) for CCS status as of January 1, 2018, for the intervention group vs the control group, with 3 levels of adjustments: baseline CCS status at January 1, 2017 (model 1), additional adjustment for women's age, marital status, income level, and region of origin (model 2), and further adjustment for the GP's sex, age, and region of origin (model 3). Two subgroup analyses, screening status at baseline and women's country of origin, were conducted to assess whether these factors had any influence on the effect of the intervention. Data were analyzed as intention to treat. Results: A total of 10 360 immigrant women, 5227 (50.4%; mean [SD] age, 44.0 [12.0] years) in the intervention group and 5133 (49.6%; mean [SD] age, 44.5 [11.6] years) in the control group, belonging to 39 general practices in the intervention area and 34 in the control area, were included in the study. The proportion of immigrant women screened increased by 2.6% in the intervention group and 0.6% in the control group. After adjustment for screening status at baseline, women in the intervention group were more likely to have participated in CCS (OR, 1.24 [95% CI, 1.11-1.38]). This statistically significant effect remained unchanged after adjustment for women's characteristics (OR, 1.24 [95% CI, 1.11-1.38]) and was reduced, but still significant, after further adjustment for GP characteristics (OR, 1.19 [95% CI, 1.06-1.34]). In subgroup analyses, the intervention particularly increased participation among women who were not previously screened at baseline (OR, 1.35 [95% CI, 1.16-1.56]), and those from Poland, Pakistan, and Somalia (OR, 1.74 [95% CI, 1.17-2.61]) when adjusting for baseline screening status. Conclusions and Relevance: Our intervention targeting general practices significantly increased CCS participation among immigrants, although the absolute effect size of 2% in the fully adjusted model was small. Engaging other primary health professionals such as midwives to perform CCS could further contribute to increasing participation. Trial Registration: ClinicalTrials.gov Identifier: NCT03155581.