Two controlled trials to determine the effectiveness of a mailed intervention to increase colon cancer screening

Colorectal cancer (CRC) screening is underutilized. Effective and efficient interventions are needed to increase its utilization in primary care.

We used UNC Internal Medicine electronic medical records to perform 2 effectiveness trials. Eligible patients had no documentation of recent CRC screening and were aged 50-75 years. The mailed intervention contained a letter documenting the need for screening signed by the attending physician in wave A and the practice director in wave B, a postcard to request a decision aid about CRC screening options, and information about how to obtain screening.

Three-hundred and forty patients of attending physicians in wave A, 944 patients of resident physicians in wave B, and 214 patients of attending physicians in wave B were included. The intervention increased screening compared with controls for attending physicians' patients in wave A (13.1% vs. 4.1%, 95% CI, 3.1%-14.9%) but not for resident physicians' patients in wave B (1.3% vs. 1.9%, 95% CI, -2.2% to 1.0%). A small increase in screening with the intervention was seen in attending physicians' patients in wave B (6.9% vs. 2.4%, 95% CI, -1.4% to 10.5%). Requests for decision aids were uncommon in both waves (12.5% wave A and 7.8% wave B).

The group assignments were not individually randomized, and covariate information to explain the differences in effect was limited.

The intervention increased CRC screening in attending physicians' patients who received a letter from their physicians, but not resident physicians' patients who received a letter signed by the practice director.