使用阿片类药物长期存在已知的风险。然而，在使用阿片类药物之后，对于阿片类药物的长期使用轨迹了解较少。本研究目的在于确定5年内处方阿片类药物使用的轨迹，并研究每个轨迹组的特征。本人口基础队列研究在澳大利亚新南威尔士州进行，将全国药物索赔数据与10个国家和州数据集相连，以确定社会人口特征、临床特征、药物使用和卫生服务使用的情况。研究对象为2003年7月1日至2018年12月31日期间开始使用处方阿片类药物的新南威尔士州居民（年龄≥18岁）。统计分析时间为2022年2月至9月。根据药物索赔数据，识别出在过去365天内没有阿片类药物使用记录的处方阿片类药物发放情况。主要观测指标是自阿片类药物启用后60个月的月度阿片类药物使用轨迹。采用基于群体轨迹模型进行轨迹分类。使用相连卫生保健数据集，研究不同轨迹组的个体特征。在开始使用处方阿片类药物的3,474,490名个体中（1,831,230名女性[52.7%]；平均[标准差]年龄49.7 [19.3]岁），确定了5种长期阿片类药物使用轨迹：非常低度使用（75.4%），低度使用（16.6%），从中度递减至低度使用（2.6%），从低度递增至中度使用（2.6%）和持续使用（2.8%）。与非常低度使用轨迹组的个体相比，持续使用轨迹组的个体年龄较大（年龄≥65岁：22.0% vs 58.4%）；具有更多的合并症，包括癌症（4.1% vs 22.2%）；与医疗机构的接触增加，包括住院治疗（36.9% vs 51.6%）；在开始使用阿片类药物之前，使用的精神药物（16.4% vs 42.4%）和其他镇痛药物（22.9% vs 47.3%）更多，并且开始使用的阿片类药物更强效（20.0% vs 50.2%）。本队列研究的结果表明，在5年的时间内，大多数开始使用处方阿片类药物的个体对阿片类药物的暴露相对较低且时间有限。少数个体持续或增加使用阿片类药物，这些个体年龄较大，存在更多合并症，使用精神药物和其他镇痛药物的情况较多，这可能反映了这些个体疼痛的患病率和治疗需求较高。

There are known risks of using opioids for extended periods. However, less is known about the long-term trajectories of opioid use following initiation.To identify 5-year trajectories of prescription opioid use, and to examine the characteristics of each trajectory group.This population-based cohort study conducted in New South Wales, Australia, linked national pharmaceutical claims data to 10 national and state data sets to determine sociodemographic characteristics, clinical characteristics, drug use, and health services use. The cohort included adult residents (aged ≥18 years) of New South Wales who initiated a prescription opioid between July 1, 2003, and December 31, 2018. Statistical analyses were conducted from February to September 2022.Dispensing of a prescription opioid, with no evidence of opioid dispensing in the preceding 365 days, identified from pharmaceutical claims data.The main outcome was the trajectories of monthly opioid use over 60 months from opioid initiation. Group-based trajectory modeling was used to classify these trajectories. Linked health care data sets were used to examine characteristics of individuals in different trajectory groups.Among 3 474 490 individuals who initiated a prescription opioid (1 831 230 females [52.7%]; mean [SD] age, 49.7 [19.3] years), 5 trajectories of long-term opioid use were identified: very low use (75.4%), low use (16.6%), moderate decreasing to low use (2.6%), low increasing to moderate use (2.6%), and sustained use (2.8%). Compared with individuals in the very low use trajectory group, those in the sustained use trajectory group were older (age ≥65 years: 22.0% vs 58.4%); had more comorbidities, including cancer (4.1% vs 22.2%); had increased health services contact, including hospital admissions (36.9% vs 51.6%); had higher use of psychotropic (16.4% vs 42.4%) and other analgesic drugs (22.9% vs 47.3%) prior to opioid initiation, and were initiated on stronger opioids (20.0% vs 50.2%).Results of this cohort study suggest that most individuals commencing treatment with prescription opioids had relatively low and time-limited exposure to opioids over a 5-year period. The small proportion of individuals with sustained or increasing use was older with more comorbidities and use of psychotropic and other analgesic drugs, likely reflecting a higher prevalence of pain and treatment needs in these individuals.