Recruiting for a randomized controlled trial from an ethnically diverse population: Lessons from the Maternal Infection and Preterm Labor Study

OBJECTIVES To determine (a) the respondents' perceptions of 4 unclear or conflicting cancer screening guidelines: prostate-specific antigen (PSA) for men over 50, mammography for wornen 40-49, colorectal screening by fecal occult blood testing (FOBT), and colonoscopy for patients over 40; and (b) the influence of various factors on the decision to order these tests. STUDY DESIGN National Canadian mail survey of randomly selected family physicians. POPULATION Family physicians in active practice (n=565) selected from rural and urban family medicine sites in 5 provinces representing the main regions in Canada. OUTCOME MEASURED Agreement with guideline statements, and decision to order screening test in 6 clinical vignettes. RESULTS Of 565 surveys mailed, 351 (62.1%) were returned. Most respondents agreed with the Canadian Task Force recommendations, and most believed that various guidelines for 3 of the 4 screens were conflicting (PSA 86.6%; mammography 67.5%. FOBT 62.4%). Patient anxiety about cancer, patient expectations of being tested, and a positive family history of cancer increased the odds that the 4 tests would be ordered. A good quality patient-MD relationship decreased the odds of ordering a mammogram. Screening decisions were also significantly influenced by the respondents' beliefs about whether screening was recommended and whether screening Could cause more harm than good. A physician's sensitivity to his or her colleagues' practice influenced screening decisions regarding PSA and mammography. CONCLUSIONS These results suggest a conceptual framework for understanding the determinants of screening behavior when guidelines are unclear or conflicting.