Psychometric Validation and Prognostic Performance of the Bedford Alzheimer Nursing‐Severity Scale in community‐dwelling persons with severe dementia (PWSD)

Abstract

AbstractBackgroundAssessment of disease severity and prognostication are germane to dementia care yet extant instruments are limited by floor effects and inadequate mortality prognostic performance. To date, the Advanced Dementia Prognostic Tool‐ADEPT(AUC = 0.68) is the best available but was validated in only nursing home residents. We aimed to investigate the psychometric properties of the 7‐item Bedford Alzheimer Nursing‐Severity Scale(BANS) in community‐dwelling people with severe dementia (PWSDs) and explore its prognostic utility.MethodPanel study Investigating Status of Cognitively impaired Elderly in Singapore is a multi‐centre prospective longitudinal study which recruited 215 PWSD, mean age 83.6±8.2 and median follow‐up 25 months. We evaluated the internal consistency reliability, factor, construct and predictive validity of BANS compared to FAST, a well‐established dementia severity tool. A 1‐year mortality prognostic index was derived from the adapted BANS and significant clinical variables.ResultFactor analysis revealed a two‐factor solution(variance 58.4%) with item‐2(sleep‐wake cycle) not loading onto any factor. Dropping item‐2(BANS‐6) revealed a single‐factor solution (variance 40.2%) and Cronbach’s α improved from 0.701(BANS) to 0.782(BANS‐6). FAST did not correlate with agitation(CMAI) and poor quality of life(QUALID), but BANS and BANS‐6 did. After adjusting for age, sex and comorbidities, BANS‐6 but not FAST was significantly associated with complications of severe dementia. A new index(comprising BANS‐6, malnourishment, age) was derived with superior mortality predictive performance (AUC = 0.68,95%CI = 0.60‐0.75) compared to BANS(AUC = 0.64,95%CI = 0.56‐0.71) and FAST(AUC = 0.52,95%CI = 0.44‐0.59).ConclusionThe 6‐item BANS(BANS‐6) outperformed FAST in predictive utility and was comparable to ADEPT’s previous mortality predictive performance (AUC = 0.68). BANS‐6 is psychometrically reliable and valid for assessing disease severity in community‐dwelling PWSD.