OBJECTIVES: Duchenne muscular dystrophy (DMD) is a rare genetic disorder characterized by progressive muscle weakness. By the early non-ambulatory phase, patients’ inability to walk substantially impacts their health-related quality of life (HRQOL). Estimating HRQOL for young patients with DMD is challenging, highlighting the need for proxy measures. This paper aims to catalogue and compare utilities for DMD and related conditions.

METHODS: We first obtained a utility estimate for US patients in the early non-ambulatory DMD phase from existing literature (0.21). After applying ± 0.03 as the minimal clinically important difference (0.18-0.24), we extracted health states with similar utilities from the Tufts Cost-Effectiveness Analysis Registry (various utility instruments, tariffs, and raters [proxy or self]). Second, we identified health states from the Registry using pre-defined keywords (e.g., wheelchair, muscle weakness, frequent falls). A clinical expert rated each health state on a scale of 0 to 10 based on its clinical similarity to the early non-ambulatory phase, and then we extracted utilities for health states with scores ≥ 8.

RESULTS: The first search identified 223 utilities. Most common health states included severe strokes (9%, N=20, utility μ=0.201), chronic liver diseases (8.1%, N=18, μ=0.204), terminal cancers (6.3%, N=14, μ=0.21), severe rheumatoid arthritis (3.1%, N=7, μ=0.222), and heart failure (3.7%, N=6, μ=0.203). Nearly all remaining health states represented the moderate to severe stages of various other diseases. The second search identified 46 utilities for health states that are highly similar to the clinical conditions of the early non-ambulatory phase. Among this sample, the mean utility was 0.32, 52% higher than the obtained estimate from existing literature.

CONCLUSIONS: When available estimates are limited, using utilities of clinically similar conditions could be a strategy for overcoming the information gap. However, it requires careful evaluation of the types of utility instruments, tariffs, and raters (proxy or self).