Psychometric properties of a scale to assess the severity of bathing disability.
OBJECTIVE
To develop and evaluate the psychometric properties of a new bathing disability scale.


METHODS
Reliability and validity study.


METHODS
General community.


METHODS
Two subsets of community-living older persons, selected from an ongoing longitudinal study, who had some degree of bathing disability or were at increased risk for bathing disability, as determined during a comprehensive assessment at 36 (N=199) and 54 (N=213) months, respectively.


METHODS
Not applicable.


METHODS
The bathing disability scale was administered at 36, 54, and 72 months, and changes in scores were assessed between 36 and 54 months and 54 and 72 months, respectively, for the 2 subsets of participants. Convergent construct validity was evaluated by comparisons with changes in activity of daily living (ADL) disability, mobility disability, and the Short Physical Performance Battery (SPPB). Discriminative construct validity was determined by comparisons according to age and physical frailty. Responsiveness was evaluated by comparisons between participants who had and had not been hospitalized and, subsequently, by plotting correlations according to the timing of these hospitalizations.


RESULTS
The test-retest reliability was high, with an intraclass correlation coefficient=0.76 (95% confidence interval=0.59-0.94). The internal consistency reliability was excellent with Cronbach alpha=0.91-0.97. Changes in scores on the bathing disability scale were positively correlated with changes in scores in ADL and mobility disability and inversely correlated with changes in scores on the SPPB. A greater decline in scores was observed among the oldest old and those who were physically frail, but these differences did not consistently achieve statistical significance. The scale was responsive to the occurrence and/or timing of intervening hospitalizations.


CONCLUSIONS
The bathing disability scale is reliable, valid, and responsive and may be suitable for use in clinical trials to evaluate the effectiveness of interventions to enhance independent bathing.
Gill
Thomas M
TM
Yale Claude D. Pepper Older Americans Independence Center, Yale University School of Medicine, New Haven, CT 06504, USA. thomas.gill@yale.edu
Gahbauer
Evelyne A
EA
Van Ness
Peter H
PH
D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D001494:Baths; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D011594:Psychometrics; D015203:Reproducibility of Results; D012111:Residence Characteristics