Department of Health Services, University of Washington, Seattle, Washington, USA.
Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA.
Am J Ind Med. 2021 Jan;64(1):13-25. doi: 10.1002/ajim.23200. Epub 2020 Nov 18.
Many injured workers are reinjured, but reinjury risk is challenging to quantify. Because many injured workers face delayed return-to-work, or return to part-time or intermittent jobs, a calendar timescale may overestimate actual work-time at risk, yielding underestimated reinjury rates. Objectives included determining: (1) reinjury risk by degree of permanent impairment and other factors, and (2) how choice of timescale affects reinjury estimates.
This retrospective cohort study included Washington State workers' compensation (WC) claims for 43,114 injured workers, linked to state wage files (2003-2018). Three timescales were used to define at-risk denominators: (1) calendar quarters; (2) quarters with any wages; and (3) full-time equivalent (FTE) quarters, defined as cumulative work hours ÷ 520. Associations between reinjury outcomes and worker, injury, job, and WC vocational rehabilitation program participation characteristics were assessed using Cox proportional hazards regression.
Overall reinjury rates were 5.9 per 100 worker-years using a calendar timescale (95% confidence interval [CI]: 5.8-6.0), 10.0 using any-wage quarters (95% CI: 9.9-10.2), and 12.5 using FTE quarters (95% CI: 12.3-12.7). Reinjury rates were highest in the first two quarters after initial injury, remaining elevated for about 4 years. Using FTE quarters, workers with ≥10% whole body impairment had a 34% higher risk of reinjury relative to workers with no permanent partial disability award (95% CI: 1.25-1.44); no difference was detected using calendar time.
Timescale substantially affects reinjury estimates and comparisons between groups with differential return-to-work patterns. Linking wage data to WC claims facilitates measurement of long-term employment, yielding more accurate reinjury estimates.
许多受伤工人会再次受伤，但受伤风险难以量化。由于许多受伤工人面临延迟重返工作岗位，或重返兼职或间歇性工作，日历时间可能会高估实际工作风险时间，从而导致受伤率被低估。目的包括确定：（1）根据永久损伤程度和其他因素确定受伤风险，（2）选择时间尺度如何影响受伤估计。
本回顾性队列研究包括华盛顿州工人赔偿（WC）对 43,114 名受伤工人的索赔，与州工资文件（2003-2018 年）相关联。使用三种时间尺度来定义风险分母：（1）日历季度；（2）有任何工资的季度；（3）全职等效（FTE）季度，定义为累计工作小时数除以 520。使用 Cox 比例风险回归评估受伤再发结果与工人、伤害、工作和 WC 职业康复计划参与特征之间的关系。
使用日历时间尺度，总体受伤再发率为每 100 工人年 5.9 例（95%置信区间[CI]：5.8-6.0），使用任何工资季度为 10.0 例（95% CI：9.9-10.2），使用 FTE 季度为 12.5 例（95% CI：12.3-12.7）。在初次受伤后的前两个季度，受伤再发率最高，大约 4 年后仍保持较高水平。使用 FTE 季度，与没有永久性部分残疾奖的工人相比，有≥10%全身损伤的工人受伤再发风险高 34%（95% CI：1.25-1.44）；使用日历时间未检测到差异。
时间尺度会极大地影响受伤再发的估计值和具有不同重返工作模式的组之间的比较。将工资数据与 WC 索赔联系起来有助于衡量长期就业情况，从而得出更准确的受伤再发估计值。
