Background General practitioners have an important role in identifying patients in need of advance care planning (ACP), and initiating ACP in advance of medical crisis. Aim: To understand patient and GP factors influencing clinical decision-making relating to a patient’s ‘need for ACP’ (NeedACP) and the likelihood of initiating ACP (LikelyACP).

Methods Experimental vignette design, manipulating patient factors (gender, age, type of disease, medical severity, openness to ACP, doctor-patient relationship, family support) and GP factors (gender, years of experience, place of training, place of practice, caseload of patients with ACP, direct personal experience in ACP, self-report attitudes towards ACP). Seventy GP’s rated NeedACP and LikelyACP for seven vignettes, yielding N = 490 observations. A mixed model ANCOVA (Type III sums of squares, random intercept) modelled significant predictors.

Results Older patients (B = 2.08, p < 0.001), with malignant or cardio-vascular disease (B = 1.01, p < 0.001), moderate (B = 1.53, p = 0.02) or high (B = 3.85, p < 0.001) medical ‘severity’, with less ‘openness to ACP’ (B = 0.81, p < 0.001) and less family support (B = 1.86, p < 0.001) were identified as being more ‘in need of ACP’. In addition to these factors, GP attitudinal support for ACP (B = 1.23, p < 0.001), self-reported competence in ACP (B = 0.75, p < 0.01) and doctor-patient relationship (B = –0.25, p = 0.01) were predictive of likely ACP.

Discussion Patients with greater mortality risk and low family support were identified as being in need of ACP, however the likelihood of initiating ACP was more sensitive to the doctor’s attitudes and patient psycho-social factors.

Conclusion Education and training materials to encourage GP involvement in ACP should target attitudes towards ACP and communication skills, rather than prognostic risk alone.