Relationship Between Hemoglobin Levels and EQ-5D-5L Utility Index in Patients With Cold Agglutinin Disease

OBJECTIVES: The relationship between hemoglobin levels and health-related quality of life, as assessed by 5-level EuroQoL 5-Dimensions (EQ-5D-5L) utility index, remains poorly understood in patients with cold agglutinin disease (CAD). EQ-5D-5L utility index is a standardized self-reported instrument used to measure health status across five dimensions: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. The current analysis aimed to investigate this relationship using data from the Phase 3 trials of sutimlimab in patients with CAD - CARDINAL (open-label single-arm with recent blood transfusion history - NCT03347396) and CADENZA (randomized double-blind placebo-controlled with no recent blood transfusion history - NCT03347422).

METHODS: Pooled data from CARDINAL and CADENZA were analyzed; each study included a 26-week Part-A and a long-term follow-up/Part-B. Hemoglobin level and EQ-5D-5L scores were collected from baseline up to Week 171. Six linear mixed-effects models were investigated to model the EQ-5D-5L utility index (US tariffs, Pickard 2019) using hemoglobin levels as a predictor; covariates such as study—CARDINAL/CADENZA, study part A/B, and their interactions with treatment were also explored.

RESULTS: Baseline and post-baseline hemoglobin and EQ-5D-5L data from 65 patients, comprising 704 observations, were considered. The best-fitting model, determined by lower Akaike Information Criterion/Bayesian Information Criterion, involved a model with random intercept and random slope with no covariate adjustment (conditional R² of 0.756), as no significant effects were found for study, study part, study-by-treatment interaction, or study-part-by-treatment interaction (all p>0.05). Coefficient estimate for hemoglobin (g/dL) (standard error) was 0.0263 (0.0056, p<0.0001).

CONCLUSIONS: Our findings suggest a direct relationship between hemoglobin levels and EQ-5D-5L utility index scores in patients with CAD. Higher hemoglobin levels were associated with increased EQ-5D-5L utility index scores, indicating a beneficial effect on the quality of life among this patient population.