title: The predictive validity of a modified Japanese Nursing Association fall risk assessment tool: A retrospective cohort study.
abstract: BACKGROUND
  Patient falls are the most common nursing care-related adverse event in hospitals. Extensive literature has been published on the predictive validity of fall risk assessment tools; however, there have been no studies examining the changes in predictive validity at different observation periods among hospital inpatients.
  
  
  OBJECTIVE
  To examine the predictive validity of a modified Japanese Nursing Association fall risk assessment tool and to compare its predictive validity at observation periods of 7, 14, 21, and 28 days.
  
  
  METHODS
  Retrospective cohort design.
  
  
  METHODS
  Twelve wards of a 600-bed university hospital in Japan.
  
  
  METHODS
  Patients 15 years and older admitted over a six-month period were enrolled. Patients were excluded if they were admitted to the intensive care unit or neuropsychiatry ward, had no fall risk assessment results within two days of admission, or had inconsistent assessment results.
  
  
  METHODS
  Falls were observed for 28 days following admission. Predictive validity was evaluated using the area under the receiver operating curve, sensitivity, specificity, and positive and negative likelihood ratios at 7-, 14-, 21-, and 28-day observation points. Faller prevalence in each observation sample was adjusted for consistency using a bootstrap sampling method. All predictive validity indices were then recalculated and compared.
  
  
  RESULTS
  A total of 4144 patients were admitted and 67 patients fell (1.6% faller prevalence) within 28 days of admission. The modified Japanese Nursing Association fall risk assessment tool showed a sensitivity of 0.82, specificity of 0.71, positive likelihood ratio of 2.83, and negative likelihood ratio of 0.26 at a cut-point of ≥6, and the area under the receiver operating curve was 0.83. Predictive validity in the 7-day observation sample was significantly higher than the 14- and 28-day samples, but no significant difference was found relative to the 21-day observation sample.
  
  
  CONCLUSIONS
  The modified Japanese Nursing Association fall risk assessment tool demonstrated good predictive validity in a Japanese university hospital, but further evaluation is needed for other validity values and reliability. The findings from this study may indicate that predictive validity indices vary by the length of observation period and faller prevalence, but these findings need to be examined further.
authors.affiliation: Gerontological Nursing, School of Health Sciences, Faculty of Medicine, University of the Ryukyus, 207 Uehara, Nishihara 903-0215, Okinawa, Japan. Electronic address: miki51@med.u-ryukyu.ac.jp.
authors.forename: Miki
authors.initials: M
authors.lastname: Higaonna
mesh_terms: D000058:Accidental Falls; D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D018570:Risk Assessment; D012956:Societies, Nursing; D055815:Young Adult
keywords: Accidental falls; Inpatients; Japan; Nursing assessment; Reproducibility of results; Risk assessment