Human Health Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan.
Division of General Internal Medicine and Health Services Research, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Department of Epidemiology, UCLA Fielding School of Public Health, Los Angeles, CA, USA.
Soc Sci Med. 2023 Oct;334:116193. doi: 10.1016/j.socscimed.2023.116193. Epub 2023 Aug 26.
Little is known about how left-digit bias- where humans tend to discretely categorize their decisions based on the left-most digit of the continuous variables-based on patients' age affects the initial diagnosis of stroke patients. The aim of this study is to examine whether there is a discontinuous change in the ordering of imaging tests for stroke at the age threshold of 40 years old, which is indicative of left-digit bias, and whether the effect varies by patient sex.
We conducted a cohort study by regression discontinuity design (RDD). We analyzed the claims database from a nationwide working-age health insurance plan in Japan. Patients who had after-hours hospital visits from January 2014 through December 2019 were included in our analysis. The exposure is patients' age, and the primary outcome was physicians' ordering imaging tests (CT or MRI) to diagnose stroke during the index visit.
Of 293,390 total visits, 48,598 visits within data-driven optimal bandwidths of 6.0 years from the cut-off of 40 years were included for the RDD analysis (mean age 40.8 years [standard deviation 3.4], female 50.5%). The baseline probability of receiving imaging tests for stroke diagnosis was 0.9%. Physicians had a higher likelihood of ordering imaging tests when patients' age was above 40 years compared with when patients' age was just below 40 years (adjusted difference, +0.51 percentage points [pp], 95%CI, +0.13 to +1.07 pp; P = 0.01). We found a significant discontinuous change in the ordering of imaging tests for stroke at 40 years for male patients (+0.84 pp, 95%CI, +0.24 to +1.69 pp; P = 0.009) but not for female patients.
Physicians have a cognitive bias in estimating stroke risk and, consistent with a left-digit bias, treat male patients aged 40 and just below differently. This pattern was observed only among male patients.
目前对于人类基于连续变量的最左边数字将其决策离散分类的左位偏差如何影响中风患者的初始诊断知之甚少。本研究旨在检验在 40 岁这一年龄阈值处，影像检查对于中风的排序是否存在不连续的变化，这种变化表明存在左位偏差，以及这种影响是否因患者性别而异。
我们采用回归不连续设计（RDD）进行了一项队列研究。我们分析了来自日本全国性工作年龄健康保险计划的索赔数据库。我们的分析纳入了 2014 年 1 月至 2019 年 12 月期间夜间就诊的患者。暴露因素为患者年龄，主要结局是医生在就诊期间是否开具影像检查（CT 或 MRI）来诊断中风。
在 293390 次就诊中，有 48598 次就诊处于 40 岁截止线前后 6.0 年的数据驱动最佳带宽内，符合 RDD 分析的要求（平均年龄为 40.8 岁[标准差为 3.4]，女性占 50.5%）。进行中风诊断影像检查的基础概率为 0.9%。与患者年龄刚低于 40 岁时相比，当患者年龄大于 40 岁时，医生更有可能开具影像检查（调整差异，+0.51 个百分点[pp]，95%置信区间[CI]：+0.13 至+1.07 pp；P=0.01）。我们发现男性患者的中风影像检查排序存在显著的不连续变化（+0.84 pp，95%CI：+0.24 至+1.69 pp；P=0.009），但女性患者中未发现这种变化。
医生在估计中风风险时存在认知偏差，且与左位偏差一致，他们对 40 岁及刚低于 40 岁的男性患者的处理方式不同。这种模式仅在男性患者中观察到。
