Multi-faceted implementation strategy to increase use of a clinical guideline for the diagnosis of deep venous thrombosis in primary care

Background: A clinical decision rule (CDR), combined with a negative D-dimer test, can safely rule out deep venous thrombosis (DVT) in primary care. This strategy is recommended by guidelines, yet uptake by GPs is low. Objective: To evaluate a multi-faceted implementation strategy aimed at increased use of the guideline recommended CDR plus D-dimer test in primary care patients with suspected DVT. Methods: This multi-faceted implementation strategy consisted of educational outreach visits, financial reimbursements and periodical newsletters. 217 Dutch GPs (implementation group) received this strategy and included patients. Effectiveness was measured through the following patient-level outcomes: (i) proportion of non-referred patients, (ii) proportion of missed DVT cases within this group and (iii) the proportion of patients in whom the guideline was applied incorrectly. Implementation outcomes ('acceptability', 'feasibility', 'fidelity' and 'sustainability') were assessed with an online questionnaire. Patient-level outcomes were compared with those of patients included by 450 GPs, uninformed about the study's purposes providing information about usual care. Results: 336 (54%) of 619 analyzable implementation group patients were not referred, missing 6 [1.8% (95% confidence interval 0.7% to 3.9%)] DVT cases. Incorrect guideline use was observed in 199 patients (32%). Self-reported acceptability, feasibility and expected sustainability were high. Guideline use increased from 42% to an expected continuation of use of 91%. Only 32 usual care GPs included 62 patients, making formal comparison unreliable. Conclusions: This multi-faceted implementation strategy safely reduced patient referral to secondary care, despite frequently incorrect application of the guideline and resulted in high acceptability, feasibility and expected sustainability.