Validation of Medicare Rehabilitation Functional Assessments in Routine Care

IMPORTANCE: 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. OBJECTIVE: 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. DESIGN, SETTING, AND PARTICIPANTS: 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. MAIN OUTCOMES AND MEASURES: 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. RESULTS: 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]; R(2) = 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%]). CONCLUSIONS AND RELEVANCE: In this large sample of older US adults, routine care rehabilitation facility functional assessments had overall moderate correlation with criterion-standard research assessments.