Recruitment difficulties in a primary care cluster randomised trial: investigating factors contributing to general practitioners' recruitment of patients

Background: Recruitment of patients by health professionals is reported as one of the most challenging steps when undertaking studies in primary care settings. Numerous investigations of the barriers to patient recruitment in trials which recruit patients to receive an intervention have been published. However, we are not aware of any studies that have reported on the recruitment barriers as perceived by health professionals to recruiting patients into cluster randomised trials where patients do not directly receive an intervention. This particular subtype of cluster trial is commonly termed a professional-cluster trial. The aim of this study was to investigate factors that contributed to general practitioners recruitment of patients in a professional-cluster trial which evaluated the effectiveness of an intervention to increase general practitioners adherence to a clinical practice guideline for acute low-back pain. Method: General practitioners enrolled in the study were posted a questionnaire, consisting of quantitative items and an open-ended question, to assess possible reasons for poor patient recruitment. Descriptive statistics were used to summarise quantitative items and responses to the open-ended question were coded into categories. Results: Seventy-nine general practitioners completed at least one item (79/94 = 84%), representing 68 practices (85% practice response rate), and 44 provided a response to the open-ended question. General practitioners recalled inviting a median of two patients with acute low-back pain to participate in the trial over a seven-month period; they reported that they intended to recruit patients, but forgot to approach patients to participate; and they did not perceive that patients had a strong interest or disinterest in participating. Additional open-ended comments were generally consistent with the quantitative data. Conclusion: A number of barriers to the recruitment of patients with acute low-back pain by general practitioners in a professional-cluster trial were identified. These barriers were similar to those that have been identified in the literature surrounding the recruitment of patients in individual patient randomised trials. To advance the evidence base for patient recruitment strategies in primary care settings, trialists undertaking professional-cluster trials need to develop and evaluate patient recruitment strategies that minimise the efforts required by practice staff to recruit patients, while also meeting privacy and ethical responsibilities and minimising the risk of selection bias. Trial registration: Australian New Zealand Clinical Trials Registry ACTRN012606000098538 (date registered 14/03/ 2006).