Margit Kooijman

104 antagonism and includes traits such as altruism, tender-mindedness, trust and modesty. Conscientiousness describes socially prescribed impulse control that facilitates task- and goal-directed behaviour, such as thinking before acting, delaying gratification, following norms and rules and planning, organizing and prioritizing tasks. Openness to experience (vs. closed-mindedness) describes the breadth, depth, originality and complexity of an individual’s mental and experiential life. The questionnaire was sent digitally to all 73 participating physiotherapists in NPCD in February 2012. Reminders by email were sent to non-responding therapists 10 and 20 days after the questionnaire was originally sent. A maximum of three years passed between treatment and sending the questionnaire, however, generally, personality is not expected to change significantly during this time. Study sample The convenience sample of this longitudinal observational study was based on data from 4072 adult (> 18 years) patients with shoulder complaints that started and finished treatment between 2009 and 2012. In NPCD, diagnosis was registered according to the International Classification of Primary Care (ICPC). All patients with ICPC L08 (shoulder complaints) or L92 (shoulder syndromes) were selected, however those with dislocations, fractures, surgery, osteoporosis, malignancies, rheumatic or neurological diseases were excluded (n = 739). Outcome measures and independent variables The outcome of the present study was patients’ change in severity of the complaint measured by the Numeric Rating Scale (NRS). The NRS ranges from 0.0-10.0 with higher scores indicating more severe complaints. Patients were asked the severity of their shoulder complaint both at the start and end of their treatment and the difference score was calculated by subtracting the baseline severity score from the discharge score. Therefore, a negative value for change in severity indicates improvement. The independent measures at the physiotherapist level extracted from NPCD at the start of treatment were age and gender. Additional independent variables on the physiotherapist level were the domain scores on each of the five dimensions of the BFI (extraversion, neuroticism, agreeableness, conscientiousness and openness to experiences). Independent measures on patient level extracted from NPCD at the start of treatment were age, gender, mode of referral (general practitioner, medical specialist or via direct access), duration of the complaint, whether it concerned a recurrent complaint (when the complaints appeared after a symptom-free period of at least four weeks and at most two years) and origination (gradually or suddenly). These characteristics including baseline severity were -first- included in the model as confounders.