Abstract

Background

Ethnic differences in placebo and nocebo responses are an important, yet underresearched, patient factor that might contribute to treatment disparities.

Purpose

The purpose of this study was to examine ethnic differences in pain trajectories following a verbal suggestion paired with a masked, inert substance (i.e., saline).

Methods

Using a quasiexperimental design, we examined differences between 21 non-Hispanic Black (NHB) participants and 20 non-Hispanic White (NHW) participants in capsaicin-related pain rating trajectories following a nondirectional verbal suggestion + saline infusion. All participants were told that the substance would “either increase pain sensation, decrease it, or leave it unchanged.” A spline mixed model was used to quantify the interaction of ethnicity and time on ratings.

Results

There was a significant Ethnicity × Time interaction effect (β = −0.28, p = .002); NHB individuals reported significantly greater increases in pain following, but not before, the verbal suggestion + saline infusion. Sensitivity analyses showed no change in primary results based on differences in education level, general pain sensitivity, or condition order.

Conclusions

The present results showed ethnic differences in pain response trajectories following a verbal suggestion + saline infusion and suggest that future research rigorously examining possible ethnic differences in placebo/nocebo responses is warranted.

中文翻译：

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生理盐水配对输注后的实验性疼痛反应的种族差异：一项拟实验研究

摘要

背景

安慰剂和nocebo反应的种族差异是重要的但尚未得到充分研究的患者因素，可能导致治疗差异。

目的

这项研究的目的是研究口头建议与被掩盖的惰性物质（即生理盐水）配对后疼痛轨迹的种族差异。

方法

使用准实验设计，我们检查了非定向口头建议+生理盐水输注后与辣椒素相关的疼痛评分轨迹中的21名非西班牙裔黑人（NHB）参与者和20名非西班牙裔白人（NHW）参与者之间的差异。所有参与者都被告知该物质将“增加疼痛感，减轻疼痛或保持不变”。样条混合模型用于量化等级之间的种族和时间的相互作用。

结果

存在显着的族裔×时间互动效应（β= −0.28，p =。002）；NHB个人报告说，言语暗示+生理盐水输注后，但并非在此之前疼痛显着增加。敏感性分析表明，基于教育程度，总体疼痛敏感性或病情顺序的差异，主要结果没有变化。

结论

目前的结果表明口头建议+生理盐水注入后疼痛反应轨迹的种族差异，并建议将来有必要严格检查安慰剂/ nocebo反应的种族差异。