Restricted mean survival time versus conventional effect summary for treatment decision-making: A mixed-methods study

Area of Science:

• Gerontology
• Health decision-making
• Biostatistics

Background:

• Conventional effect summaries (relative risk reduction, number needed to treat) are standard for treatment effects.
• Restricted mean survival time (RMST) offers an alternative by quantifying event-free days.
• Older adults' preferences between these summary measures remain understudied.

Purpose of the Study:

• To investigate older adults' preferences for different treatment effect summary measures.
• To compare decision conflict when using conventional versus RMST-based decision aids.
• To explore qualitative perspectives on preferred methods for summarizing treatment effects.

Main Methods:

• A mixed-methods study involving a quantitative survey and qualitative interviews.
• 102 older adults with hypertension were surveyed, randomized to conventional or RMST-based decision aids.
• 23 participants underwent semi-structured interviews for in-depth perspectives.

Main Results:

• The RMST-based decision aid group showed a trend towards lower decision conflict (p=0.06) and a significantly higher proportion of participants with decision conflict scale (DCS) <25 (p=0.04).
• Qualitative findings indicated preferences were influenced by comprehension, clarity of visual aids, and information inclusion.
• Older adults' ability to understand quantitative information was key, irrespective of the summary measure used.

Conclusions:

• A time-based effect summary, such as RMST, may help reduce uncertainty for older adults in treatment decisions.
• While not statistically significant in this study, RMST showed a promising trend in reducing decision conflict.
• Presenting both conventional and RMST-based information in decision aids could cater to diverse patient preferences.