Correlation of patient-reported outcome measures to performance-based function in critical care survivors: PREDICTABLE.

BACKGROUND: Establishing sequela following critical illness is a public health priority; however, recruitment and retention of this cohort make assessing functional outcomes difficult. Completing patient-reported outcome measures (PROMs) via telephone may improve participant and researcher involvement; however, there is little evidence regarding the correlation of PROMs to performance-based outcome measures in critical care survivors. OBJECTIVES: The objective of this study was to assess the relationship between self-reported and performance-based measures of function in survivors of critical illness. METHODS: This was a nested cohort study of patients enrolled within a previously published study determining predictors of disability-free survival. Spearman's correlation (rs) was calculated between four performance-based outcomes (the Functional Independence Measure [FIM], 6-min walk distance [6MWD], Functional Reach Test [FRT], and grip strength) that were collected during a home visit 6 months following their intensive care unit admission, with two commonly used PROMs (World Health Organization Disability Assessment Scale 2.0 12 Level [WHODAS 2.0] and EuroQol-5 Dimension-5 Level [EQ-5D-5L]) obtained via phone interview (via the PREDICT study) at the same time point. RESULTS: There were 38 PROMs obtained from 40 recruited patients (mean age = 59.8 ± 16 yrs, M:F = 24:16). All 40 completed the FIM and grip strength, 37 the 6MWD, and 39 the FRT. A strong correlation was found between the primary outcome of the WHODAS 2.0 with all performance-based outcomes apart from grip strength where a moderate correlation was identified. Although strong correlations were also established between the EQ-5D-5L utility score and the FIM, 6MWD, and FRT, it only correlated weakly with grip strength. The EQ-5D overall global health rating only had very weak to moderate correlations with the performance-based outcomes. CONCLUSION: The WHODAS 2.0 correlated stronger across multiple performance-based outcome measures of functional recovery and is recommended for use in survivors of critical illness.