Validation of Medicare Rehabilitation Functional Assessments in Routine Care

Assessment of functional outcomes is currently limited by a lack of large data sets. Functional assessments are included in Medicare rehabilitation assessment files, yet the validity of these measures in routine care is unknown.

To evaluate the validity of individual-level routine care functional assessments in Medicare rehabilitation settings compared with criterion-standard National Health and Aging Trends Study (NHATS) research assessments obtained no more than 90 days later.

This cross-sectional study of individuals aged 65 years and older used the 2011 to 2015 NHATS linked with Medicare assessment files. Individuals with a discharge assessment from inpatient rehabilitation facilities, skilled nursing facilities, or home health agencies and a criterion-standard NHATS assessment were included. Data analysis was performed June 2019 to November 2019.

Summary functional assessment based on independence with eating, toilet hygiene, bathing, dressing, transfers, and mobility or walking. Linear regression was used to assess agreement between the 2 scales, adjusting for time between assessments and rehabilitation setting.

A total of 1036 adults aged 65 years and older (671 [64.8%] aged ≥80 years; 670 [64.7%] women; 685 [66.1%] white participants) met the study criteria. The correlation of the assessments was 0.63 (95% CI, 0.59 to 0.66; mean [SD] rehabilitation score, 27.5 [7.2]; mean [SD] NHATS score, 30.5 [10.1]). The correlation increased to 0.66 (95% CI, 0.60 to 0.71) for assessments no more than 30 days apart. The linear regression model adjusting for rehabilitation setting and days between evaluations found the assessments were strongly correlated (β = 1.00 [95% CI, 0.93 to 1.08]; intercept, 0.72 [95% CI, -1.79 to 3.24]; R2 = 0.42). Differences in scores were generally small (mean [SD] of NHATS - rehabilitation score, 2.96 [7.91]), and only 59 assessments (5.7%) differed by more than 2 SDs of the mean difference. Rehabilitation service scores were typically higher than NHATS scores in individuals with lower mean scores; however, the population with lower mean scores was small (156 [15.1%]).

In this large sample of older US adults, routine care rehabilitation facility functional assessments had overall moderate correlation with criterion-standard research assessments.