The Diagnostic Accuracy of Subjective Screening for Identifying Mobility Impairment in Older Adults.

BACKGROUND AND PURPOSE: Identifying preclinical mobility limitation (PCML) and mobility disability are critical for a preventative model of physical therapy. Subjective fall risk and mobility screening questions are used to determine the need for objective testing. This study aimed to determine the diagnostic accuracy of subjective screening for mobility impairment.

METHODS

Participants answered 8 evidence-based subjective fall risk and mobility screening questions followed by evaluation with the Short Physical Performance Battery (SPPB) and the grip strength test. Gait speed and the Five Times Sit to Stand Test time were calculated from the SPPB. Reference standards for the tests were used to binarize results as at/above or below standards. Relationships between binarized subjective screening and objective test results were analyzed with Phi (φ) correlation coefficients. Sensitivity and specificity were calculated for relationships with acceptable cutoff values ( P < .05, φ  > 0.3). Binomial regression was used to determine the sensitivity and specificity of asking multiple questions. Screening questions were considered useful predictors of the objective test result if combined sensitivity and specificity were ≥1.5.

RESULTS AND DISCUSSION: Ambulatory adults (N = 83) aged 65 to 92 years ( M = 70) participated. One question-"Do you have difficulty with balance?"-met the diagnostic accuracy threshold for predicting the SPPB outcome with a sensitivity of 0.632 and a specificity of 0.871.

CONCLUSIONS

Subjective screening does not adequately predict objective test results for identifying PCML. The findings indicate that improved screening tools or more referrals for objective testing are needed to detect early mobility loss with aging.