Health-related quality of life correlates with patient-reported and proxy-reported disability in critical illness survivors: a secondary analysis of the ERIC trial.

BACKGROUND

Expanding follow-up services for survivors of critical illness requires short and reliable instrument sets. The WHO Disability Assessment Schedule (WHODAS) 2.0 and the EuroQol 5-Dimensions 5-Level (EQ-5D-5L) are recommended to assess disability and health-related quality of life (HrQoL), respectively. As they may measure partially overlapping constructs, we assessed their relationship.

METHODS

We conducted a secondary analysis of the multicenter cluster-randomized controlled Enhanced Recovery after Intensive Care (ERIC) trial (ClinicalTrials.gov: NCT03671447). At follow-ups scheduled 6 months after ICU discharge, critical illness survivors and caregivers completed the EQ-5D-5L, the patient-reported and the proxy-reported 12-item WHODAS 2.0. We employed local polynomial regressions, correlation coefficients, and linear regressions to analyze the global and domain-specific relationships between the EQ-5D-5L and the WHODAS 2.0.

RESULTS

We analyzed 700 patients with a median EQ-5D-5L index value of 0.81 [IQR 0.52 to 0.94], a median patient-reported WHODAS 2.0 sum score of 11 [IQR 3 to 23], and a median proxy-reported WHODAS 2.0 sum score of 16 [IQR 6 to 28]. The EQ-5D-5L index value highly correlated with patient-reported (Spearman: - 0.84 [95% CI - 0.86 to - 0.82]) and proxy-reported (Spearman: - 0.70 [- 0.76 to - 0.64]) WHODAS 2.0 sum scores. Corresponding domains were also highly correlated, with the patient-reported WHODAS 2.0 aligning more closely with the EQ-5D-5L than the proxy-reported WHODAS 2.0. We found ceiling and floor effects for both instruments, indicating limitations for detecting mild disabilities and high HrQoL. In multivariable linear regressions, the patient-reported and proxy-reported WHODAS 2.0 sum scores (both - 0.02 [95% CI - 0.02 to - 0.02], p < 0.01) and WHODAS 2.0 domain scores for mobility, self-care, and life activities were predictors of the EQ-5D-5L index value and respective EQ-5D-5L domain scores.

CONCLUSIONS

Our results suggest a high correlation between the patient-reported and proxy-reported WHODAS 2.0 and the EQ-5D-5L, particularly in their corresponding domains. To economize post-ICU assessments, there may be no need to use both instruments simultaneously.