Health Utility during the First Two Years of Treatment of Hematological Malignancies

Background

There are limited patient reported outcomes for acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) due to relatively low incidence rates and disease severity. Patient reported outcomes on health utility, a measure of quality of life weighted to the preferences of the general population, are however required for economic evaluation of interventions to diagnose and treat the diseases. This study was designed to report health utility outcomes from patients during their treatment for AML and MDS, for the first time. We sought to use the infrastructure of a multicentre study to report these outcomes in an otherwise inaccessible patient population and enable more accurate economic models.

Methods

Following institutional research ethics board approval at six recruiting study centres across Canada, the Euroqol five dimensions (EQ5D) health utility instrument and socio-demographic questionnaires were administered by telephone or in person to eligible participants in a national clinical study (NCT01685619). These data were linked to the treatment outcomes and health state transitions of each participant during their treatment of AML or MDS. A longitudinal analysis of treatment effects and cross-sectional regression analyses were undertaken for data collected at four, quarterly time points over the first year following diagnosis, and two semi-annual points over the second year. We defined health utility for specific economic health states and the co-varying impacts from socio-demographic characteristics and treatment-related impacts.

Results

At least one quality of life questionnaire was returned for 131 (96%) of the eligible patients who participated in the study. Response rates were greater than 60% at each of the scheduled time points. The median overall survival (468 days; 95% CI: 353-660) was reached over the 24 month term of follow-up. The most preferred health states involved greater than 12 months of survival (health utility > 0.78); the least preferred health states were reported for failed treatments and an initial AML diagnosis (health utility < 0.63). There were no significant differences found among utility outcomes that could be related to consolidation modality or remission induction intent. AML patients with 24 months of survival gained 0.037 more quality adjusted life years (QALYs) than MDS patients with equivalent survival time. An ordinary least squares regression model on the cross-sectional data suggests that having an MDS diagnosis was associated with a better short-term health utility while long term outcomes were greater for patients who survived 24 months after being diagnosed with AML (p<0.1).

Conclusions

This report on health utility outcomes was made possible only by collaboration with health economists and the infrastructure of a multicentre clinical study. The data suggest that survivors following 24 months of treatment for AML gained more QALYs than the survivors of MDS. The findings warrant further investigation due to the suggestion of equivalent health utility between treatments and to further validate the use of the EQ5D instrument in this disease area.