Associations of Patient-Reported and Objective Measures of Mobility With Prospective Falls in Older Adults with Multiple Sclerosis.

OBJECTIVE: The patient determined disease steps (PDDS) scale is a valid measure of mobility disability in multiple sclerosis (MS). The short physical performance battery (SPPB) is a gold standard objective measures of physical function. However, whether the PDDS and SPPB are associated with prospective falls in older adults with MS (OAMS) has not been reported. The current study addressed this gap in the literature by evaluating and comparing associations of both measures with prospective falls in this patient population. DESIGN: Prospective cohort study SETTING: Community PARTICIPANTS: Ambulatory OAMS (n=109, mean age=64.74±4.3ys, %female=69.7). INTERVENTIONS: Not applicable MAIN OUTCOME MEASURES: Participants completed the PDDS and SPPB during in-person study visits and reported falls using a structured monthly telephone interview during follow-up that varied depending on participants' enrollment date into the study (mean duration of follow-up in years = 2.24±1.40). RESULTS: PDDS and SPPB scores were standardized based on sample distribution and General Estimating Equations (GEE) models were utilized to evaluate and compare their associated odds ratios with prospective falls. One standard deviation increases in PDDS and SPPB scores were associated with an increase of 27.7% (OR=1.277, 95%CI=1.034 to 1.576, p=.023) and a decrease of 25.1% (OR=.749, 95%CI=.617 to .910, p=.004) in the odds of falling, respectively. Two one-sided test (TOST) results showed that the PDDS and SPPB were equivalent with respect to their associations with prospective falls (p=0.039). CONCLUSIONS: Associations of the PDDS and SPPB with prospective falls were significant and comparable among OAMS. Thus, the PDDS, a simple-to-administer patient-reported outcome measure, could be used to inform falls risk assessment procedures as well as the design of observational or intervention studies of falls in OAMS.