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

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.

Restricted mean survival time versus conventional measures for treatment decision-making.

BACKGROUND/OBJECTIVES: Restricted mean survival time (RMST) summarizes treatment effect in terms of a gain or loss in the event-free days. It remains uncertain whether communicating treatment benefit and harm using RMST-based summary is more effective than conventional summary based on absolute and relative risk reduction. We compared the effect of RMST-based approach and conventional approach on decisional conflict using an example of intensive versus standard blood pressure-lowering strategies. DESIGN: On-line survey. SETTING: A convenience sample of patients in the United States. PARTICIPANTS: Two hundred adults aged 65 and older with hypertension requiring anti-hypertensive treatment (response rate 85.5%). INTERVENTIONS: Participants were randomly assigned to either RMST-based summary or conventional summary about the benefit and harm of blood pressure-lowering strategies. MEASUREMENTS: Decisional Conflict Scale (DCS), ranging from 0 (no conflict) to 100 (high conflict), and preference for intensive blood pressure-lowering strategy. RESULTS: Participants assigned to RMST-based approach (n = 100) and conventional approach (n = 100) had similar age (mean [standard deviation, SD]: 72.3 [5.6] vs 72.8 [5.5] years) and proportions of female (50 [50.0%] vs 61 [61.0%]) and white race (92 [92.0%] vs 92 [92.0%]). The mean (SD) DCS score was 25.2 (15.0) for RMST-based approach and 25.6 (14.1) for conventional approach (p = 0.84). The number (%) of participants who preferred intensive strategy was 10 (10.0%) for RMST-based approach and 14 (14.0%) for conventional approach (p = 0.52). The results were consistent in subgroups defined by age, sex, education level, cardiovascular disease status, and predicted mortality risk categories. CONCLUSION: In a sample of relatively healthy older adults with hypertension, RMST-based approach was as effective as conventional approach on decisional conflict about choosing a blood pressure-lowering strategy. This study provides proof-of-concept evidence that RMST-based approach can be used in conjunction with absolute and relative risk reduction for communicating treatment benefit and harm in a decision aid.

Low-Magnitude Mechanical Stimulation to Improve Bone Density in Persons of Advanced Age: A Randomized, Placebo-Controlled Trial.

Nonpharmacologic approaches to preserve or increase bone mineral density (BMD) include whole-body vibration (WBV), but its efficacy in elderly persons is not clear. Therefore, we conducted the Vibration to Improve Bone in Elderly Subjects (VIBES) trial, a randomized, placebo-controlled trial of 10 minutes of daily WBV (0.3g at 37 Hz) in seniors recruited from 16 independent living communities. The primary outcomes were volumetric BMD of the hip and spine measured by quantitative computed tomography (QCT) and biochemical markers of bone turnover. We randomized 174 men and women (89 active, 85 placebo) with T-scores -1 to -2.5 who were not taking bone active drugs and had no diseases affecting the skeleton (mean age 82 ± 7 years, range 65 to 102). Participants received daily calcium (1000 mg) and vitamin D (800 IU). Study platforms were activated using radio frequency ID cards providing electronic adherence monitoring; placebo platforms resembled the active platforms. In total, 61% of participants in the active arm and 73% in the placebo arm completed 24 months. The primary outcomes, median percent changes (interquartile range [IQR]) in total volumetric femoral trabecular BMD (active group (2.2% [-0.8%, 5.2%]) versus placebo 0.4% [-4.8%, 5.0%]) and in mid-vertebral trabecular BMD of L1 and L2 (active group (5.3% [-6.9%, 13.3%]) versus placebo (2.4% [-4.4%, 11.1%]), did not differ between groups (all p values > 0.1). Changes in biochemical markers of bone turnover (P1NP and sCTX) also were not different between groups (p = 0.19 and p = 0.97, respectively). In conclusion, this placebo-controlled randomized trial of daily WBV in older adults did not demonstrate evidence of significant beneficial effects on volumetric BMD or bone biomarkers; however, the high variability in vBMD changes limited our power to detect small treatment effects. The beneficial effects of WBV observed in previous studies of younger women may not occur to the same extent in elderly individuals.

Tai Chi for osteopenic women: design and rationale of a pragmatic randomized controlled trial.

BACKGROUND: Post-menopausal osteopenic women are at increased risk for skeletal fractures. Current osteopenia treatment guidelines include exercise, however, optimal exercise regimens for attenuating bone mineral density (BMD) loss, or for addressing other fracture-related risk factors (e.g. poor balance, decreased muscle strength) are not well-defined. Tai Chi is an increasingly popular weight bearing mind-body exercise that has been reported to positively impact BMD dynamics and improve postural control, however, current evidence is inconclusive. This study will determine the effectiveness of Tai Chi in reducing rates of bone turnover in post-menopausal osteopenic women, compared with standard care, and will preliminarily explore biomechanical processes that might inform how Tai Chi impacts BMD and associated fracture risks. METHODS/DESIGN: A total of 86 post-menopausal women, aged 45-70y, T-score of the hip and/or spine -1.0 and -2.5, have been recruited from primary care clinics of a large healthcare system based in Boston. They have been randomized to a group-based 9-month Tai Chi program plus standard care or to standard care only. A unique aspect of this trial is its pragmatic design, which allows participants randomized to Tai Chi to choose from a pre-screened list of community-based Tai Chi programs. Interviewers masked to participants' treatment group assess outcomes at baseline and 3 and 9 months after randomization. Primary outcomes are serum markers of bone resorption (C-terminal cross linking telopeptide of type I collagen), bone formation (osteocalcin), and BMD of the lumbar spine and proximal femur (dual-energy X-ray absorptiometry). Secondary outcomes include health-related quality-of-life, exercise behavior, and psychological well-being. In addition, kinetic and kinematic characterization of gait, standing, and rising from a chair are assessed in subset of participants (n = 16) to explore the feasibility of modeling skeletal mechanical loads and postural control as mediators of fracture risk. DISCUSSION: Results of this study will provide preliminary evidence regarding the value of Tai Chi as an intervention for decreasing fracture risk in osteopenic women. They will also inform the feasibility, value and potential limitations related to the use of pragmatic designs for the study of Tai Chi and related mind-body exercise. If the results are positive, this will help focus future, more in-depth, research on the most promising potential mechanisms of action identified by this study. TRIAL REGISTRATION: This trial is registered in ClinicalTrials.gov, with the ID number of NCT01039012.