Chestnut Health Systems, 448 Wylie Drive, Normal, IL 61761, USA.
RAND Corporation, 1200 South Hayes Street, Arlington, VA 22202, USA.
J Subst Abuse Treat. 2022 Jan;132:108637. doi: 10.1016/j.jsat.2021.108637. Epub 2021 Oct 8.
In a recently published randomized controlled trial (RCT) of Volunteer Recovery Support for Adolescents (VRSA), a secondary finding indicated that better adherence to planned VRSA telephone session frequency resulted in significantly higher remission rates relative to lower session adherence. However, interpretation of this dose-response relationship may have been confounded by participant characteristics such as baseline levels of substance use and mental health problems.
The present study used statistical methods designed to approximate RCTs when comparing more than two nonequivalent groups that include an assessment of the potential impact of omitted variables. Classification and Regression Tree (CRT) analysis was used to establish the cut-point between high (H) and low (L) VRSA dosage groups. Because we were interested in generalizing to youth with poor attendance, the L-VRSA group served as the reference group. Balancing weights for H-VRSA and a services as usual (SAU) control group were calculated to ensure similarity of baseline pretreatment characteristics to the reference group, and sensitivity of findings to unobserved confounding variables was assessed.
Findings suggested that superior remission rates at the end of the intervention phase were the result of high adherence to planned VRSA session frequency. Recommendations to achieve high VRSA participation among a larger segment of youth and to test whether longer VRSA duration improves the stability of recovery outcomes are provided.
Few published dose-response studies have adequately controlled for selection confounds from both observed and unobserved confounding. As such, the present study aims to both assess the impact of different dosage levels of VRSA and provide a template for how to apply state-of-the-art statistical methods designed to approximate randomized controlled trials to such studies.
在最近发表的一项志愿者康复支持青少年(VRSA)的随机对照试验(RCT)中,一个次要发现表明,与较低的疗程依从性相比,更好地遵循计划的 VRSA 电话疗程频率会导致缓解率显著提高。然而,这种剂量-反应关系的解释可能受到参与者特征的混淆,如基线物质使用和心理健康问题的水平。
本研究使用了旨在模拟 RCT 的统计方法,比较了超过两个不等效的组,包括评估遗漏变量的潜在影响。分类和回归树(CRT)分析用于确定高(H)和低(L)VRSA 剂量组之间的分界点。由于我们有兴趣推广到出勤率差的青少年,因此低 VRSA 组作为参考组。为了确保基线预处理特征与参考组相似,并评估对未观察到的混杂变量的发现的敏感性,计算了高 VRSA 和常规服务(SAU)对照组的平衡权重。
研究结果表明,在干预阶段结束时,较高的缓解率是由于高度遵循计划的 VRSA 疗程频率所致。提出了一些建议,以实现更多青少年对 VRSA 的高度参与,并检验更长的 VRSA 持续时间是否能提高康复结果的稳定性。
很少有发表的剂量-反应研究充分控制了观察到和未观察到的混杂因素的选择混淆。因此,本研究旨在评估 VRSA 的不同剂量水平的影响,并提供如何应用旨在模拟随机对照试验的最新统计方法的模板。