Incorporating Patient Perspectives into a Composite Score for Measuring Disease Progression in Spinocerebellar Ataxia...

Area of Science:

• Neurology
• Biostatistics
• Patient-Reported Outcomes

Background:

• The spinocerebellar ataxia composite score (SCACOMS) uses functional Scale for the Assessment and Rating of Ataxia (f-SARA) and Clinician Global Impression of Change (CGI-C) items.
• Item weights were initially determined by partial least squares (PLS) regression for optimal responsiveness.

Purpose of the Study:

• To integrate patient feedback into SCACOMS item weights.
• To assess the responsiveness of the reweighted composite scale.
• To discuss implications for future use of the SCACOMS.

Main Methods:

• Compared PLS-derived weights with patient-assigned importance from interviews.
• Adjusted SCACOMS weights using a 50/50 combination and by reducing CGI-C weight to 20%.
• Evaluated scale responsiveness using 1-year mean to standard deviation ratios (MSDRs).

Main Results:

• The original PLS-derived SCACOMS showed the highest MSDR (0.99).
• Averaging weights resulted in an MSDR of 0.91.
• Reducing CGI-C weight to 20% yielded an MSDR of 0.79.

Conclusions:

• Incorporating patient feedback enhances SCACOMS face validity and patient centricity.
• This integration comes at the cost of reduced sensitivity to detect change.
• The trade-off between patient centricity and sensitivity requires careful consideration for clinical application.