Validation of the Behavioural Observation Scale 3 for the evaluation of pain in adults.

BACKGROUND: Many behavioural scales are available to assess pain but none are suitable for a quick evaluation of non-sedated and non-geriatric adults. The Behavioural Observation Scale 3 (BOS-3) is short, composed of five items. This study examined its feasibility and diagnostic performances. METHODS: Adult patients were included from medical and surgical departments of the University Hospital of Bordeaux. In a cross-sectional study, BOS-3 was compared to Numerical Rate Scale (NRS) with communicating patients (CP) and Behavioural Scale for the Elderly Person (ECPA2) with non-communicating patients (NCP). Each time, BOS-3 and reference scale were performed by an internal caregiver and an external expert. RESULTS: We included 447 patients: 395 communicating and 52 non-communicating. All patients were assessed by the BOS-3 and the reference test. All BOS-3 were carried out in less than one minute with only four missing data. Its reproducibility (ICC = 0.77 [95% CI 0.73-0.81] with CP and 0.93 [95% CI 0.89-0.97] with NCP) and its internal consistency (Cronbach α = 0.67 with CP and 0.70 with NCP) were good. In non-communicating patients, ROC analysis set a threshold at 3 on 10. Sensitivity was 0.87 [95% CI 0.77-0.96], specificity 0.97 [95% CI 0.93-1.00], positive predictive value 0.93 [95% CI 0.86-0.99] and negative predictive value 0.95 [95% CI 0.89-1.00]. In communicating patients, sensitivity decreased to 0.34 [95% CI 0.28-0.38] but specificity reached 0.96 [95% CI 0.94-0.98] and positive predictive value 0.75 [95% CI 0.70-0.79]. CONCLUSIONS: BOS-3 had good metrological properties in non-communicating adults. With communicating patients, a positive BOS-3 could be an additional tool to confirm pain, when underestimated on the NRS. SIGNIFICANCE: This study describes the diagnostic performances of a behavioral pain assessment scale designed for non-geriatric and non-sedated adults. The results show its validity in non-communicating patients and suggest its usefulness as an ancillary tool in communicating patients in whom simple numerical scales are often insufficient.