A Multicenter Cluster Randomized Controlled Trial of Strategies to Improve Thyroid Function Testing

OBJECTIVES: This project aimed to compare the independent and combined effectiveness of two implementation interventions of guidelines for ordering thyroid function tests: a Memorandum Pocket Card (MPC) and a Test Request Form (TRF). RESEARCH DESIGN: Intervention groups were wards. The study used an experimental 2*2 factorial design with matching hospitals according to size and activity and wards according to preintervention appropriateness for test ordering. Four ward groups were established: the dual intervention group, the order form group, the pocket card group and the control group. Physicians in all groups received guidelines and were invited to a local information meeting. MEASURES: The main outcome measure of effectiveness was the Guideline Conformity Rate (GCR). RESULTS: Six hospitals participated in the study (two middle-sized hospitals, two small-sized hospitals and two psychiatric hospitals). A total of 1412 orders for thyroid function tests were collected. GCR was 78% in the dual intervention group, 83% in the order form group, 73% in the pocket card group and 62% in the control group. The interaction between TRF and MPC was not significant (beta = -0.70; P = 0.21). Compared with simple information, TRF was effective in increasing GCR (OR, 2.65; 95% CI, 1.52-4.62), unlike MPC (OR, 1.28; CI, 0.75-2.19). CONCLUSIONS: Using a robust design, our study shows the greater effectiveness of TRF than MPC and their association in implementing thyroid function test guidelines.