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

Abstract

Background Treatment effect is typically summarized in terms of relative risk reduction or number needed to treat (“conventional effect summary”). Restricted mean survival time (RMST) summarizes treatment effect in terms of a gain or loss in event‐free days. Older adults' preference between the two effect summary measures has not been studied. Methods We conducted a mixed methods study using a quantitative survey and qualitative semi‐structured interviews. For the survey, we enrolled 102 residents with hypertension at five senior housing facilities (mean age 81.3 years, 82 female, 95 white race). We randomly assigned respondents to either RMST‐based (n = 49) or conventional decision aid (n = 53) about the benefits and harms of intensive versus standard blood pressure‐lowering strategies and compared decision conflict scale (DCS) responses (range: 0 [no conflict] to 100 [maximum conflict]; <25 is associated with implementing decisions). We used a purposive sample of 23 survey respondents stratified by both their random assignment and DCS from the survey. Inductive qualitative thematic analysis explored complementary perspectives on preferred ways of summarizing treatment effects. Results The mean (standard deviation) total DCS was 22.0 (14.3) for the conventional decision aid group and 16.7 (14.1) for the RMST‐based decision aid group (p = 0.06), but the proportion of participants with a DCS <25 was higher in the RMST‐based group (26 [49.1%] vs 34 [69.4%]; p = 0.04). Qualitative interviews suggested that, regardless of effect summary measure, older individuals' preference depended on their ability to clearly comprehend quantitative information, clarity of presentation in the visual aid, and inclusion of desired information. Conclusions When choosing a blood pressure‐lowering strategy, older adults' perceived uncertainty may be reduced with a time‐based effect summary, although our study was underpowered to detect a statistically significant difference. Given highly variable individual preferences, it may be useful to present both conventional and RMST‐based information in decision aids.

Prognostic nomogram and epidemiological analysis for lung atypical carcinoid: A SEER database and external validation study

“…Here, RMST is a sophisticated statistical measure used in the analysis of survival data, summarising the entire area under the survival curve up to a specified time point. It could provide an intuitive, clinically relevant measure of average expected survival time without meeting standard of proportional hazards assumption 16,17 …”

“…It could provide an intuitive, clinically relevant measure of average expected survival time without meeting standard of proportional hazards assumption. 16 , 17 …”