Jeffrey Karen, Woolford Lana, Maini Rishma, Basetti Siddharth, Batchelor Ashleigh, Weatherill David, White Chris, Hammersley Vicky, Millington Tristan, Macdonald Calum, Quint Jennifer K, Kerr Robin, Kerr Steven, Shah Syed Ahmar, Rudan Igor, Fagbamigbe Adeniyi Francis, Simpson Colin R, Katikireddi Srinivasa Vittal, Robertson Chris, Ritchie Lewis, Sheikh Aziz, Daines Luke
Usher Institute, University of Edinburgh, Edinburgh, UK.
Public Health Scotland, Glasgow and Edinburgh, UK.
EClinicalMedicine. 2024 Apr 11;71:102590. doi: 10.1016/j.eclinm.2024.102590. eCollection 2024 May.
Long COVID is a debilitating multisystem condition. The objective of this study was to estimate the prevalence of long COVID in the adult population of Scotland, and to identify risk factors associated with its development.
In this national, retrospective, observational cohort study, we analysed electronic health records (EHRs) for all adults (≥18 years) registered with a general medical practice and resident in Scotland between March 1, 2020, and October 26, 2022 (98-99% of the population). We linked data from primary care, secondary care, laboratory testing and prescribing. Four outcome measures were used to identify long COVID: clinical codes, free text in primary care records, free text on sick notes, and a novel operational definition. The operational definition was developed using Poisson regression to identify clinical encounters indicative of long COVID from a sample of negative and positive COVID-19 cases matched on time-varying propensity to test positive for SARS-CoV-2. Possible risk factors for long COVID were identified by stratifying descriptive statistics by long COVID status.
Of 4,676,390 participants, 81,219 (1.7%) were identified as having long COVID. Clinical codes identified the fewest cases (n = 1,092, 0.02%), followed by free text (n = 8,368, 0.2%), sick notes (n = 14,469, 0.3%), and the operational definition (n = 64,193, 1.4%). There was limited overlap in cases identified by the measures; however, temporal trends and patient characteristics were consistent across measures. Compared with the general population, a higher proportion of people with long COVID were female (65.1% versus 50.4%), aged 38-67 (63.7% versus 48.9%), overweight or obese (45.7% versus 29.4%), had one or more comorbidities (52.7% versus 36.0%), were immunosuppressed (6.9% versus 3.2%), shielding (7.9% versus 3.4%), or hospitalised within 28 days of testing positive (8.8% versus 3.3%%), and had tested positive before Omicron became the dominant variant (44.9% versus 35.9%). The operational definition identified long COVID cases with combinations of clinical encounters (from four symptoms, six investigation types, and seven management strategies) recorded in EHRs within 4-26 weeks of a positive SARS-CoV-2 test. These combinations were significantly (p < 0.0001) more prevalent in positive COVID-19 patients than in matched negative controls. In a case-crossover analysis, 16.4% of those identified by the operational definition had similar healthcare patterns recorded before testing positive.
The prevalence of long COVID presenting in general practice was estimated to be 0.02-1.7%, depending on the measure used. Due to challenges in diagnosing long COVID and inconsistent recording of information in EHRs, the true prevalence of long COVID is likely to be higher. The operational definition provided a novel approach but relied on a restricted set of symptoms and may misclassify individuals with pre-existing health conditions. Further research is needed to refine and validate this approach.
Chief Scientist Office (Scotland), Medical Research Council, and BREATHE.
新冠后遗症是一种使人衰弱的多系统疾病。本研究的目的是估计苏格兰成年人口中新冠后遗症的患病率，并确定与其发生相关的风险因素。
在这项全国性的回顾性观察队列研究中，我们分析了2020年3月1日至2022年10月26日期间在苏格兰注册并居住在当地的所有成年人（≥18岁）的电子健康记录（EHR）（覆盖98 - 99%的人口）。我们将来自初级保健、二级保健、实验室检测和处方的数据进行了关联。使用了四种结局指标来识别新冠后遗症：临床编码、初级保健记录中的自由文本、病假条上的自由文本以及一种新的操作定义。该操作定义是通过泊松回归开发的，以从一组根据检测SARS-CoV-2呈阳性的时变倾向匹配的新冠阴性和阳性病例样本中识别出表明新冠后遗症的临床接触情况。通过按新冠后遗症状态对描述性统计进行分层，确定了新冠后遗症可能的风险因素。
在4,676,390名参与者中，81,219人（1.7%）被确定患有新冠后遗症。临床编码识别出的病例最少（n = 1,092，0.02%），其次是自由文本（n = 8,36８，0.2%）、病假条（n = 14,469，0.3%）以及操作定义（n = 64,193，1.4%）。这些指标识别出的病例重叠有限；然而，不同指标的时间趋势和患者特征是一致的。与普通人群相比，新冠后遗症患者中女性比例更高（65.1%对50.4%）、年龄在38 - 67岁之间（63.7%对48.9%）、超重或肥胖（45.7%对29.4%）、有一项或多项合并症（52.7%对36.0%）、免疫抑制（6.9%对3.2%）、接受防护（7.9%对3.4%）或在检测呈阳性后２８天内住院（8.8%对3.3%），并且在奥密克戎成为主要变异株之前检测呈阳性（44.9%对35.9%）。操作定义识别出在SARS-CoV-2检测呈阳性后的4 - 26周内，电子健康记录中记录有临床接触情况（来自四种症状、六种检查类型和七种管理策略）组合的新冠后遗症病例。这些组合在新冠阳性患者中比在匹配的阴性对照中显著更常见（p < 0.0001）。在病例交叉分析中，通过操作定义识别出的患者中有16.４%在检测呈阳性之前有类似的医疗模式记录。
根据所使用的指标，初级保健中出现的新冠后遗症患病率估计为0.02 - 1.7%。由于诊断新冠后遗症存在挑战以及电子健康记录中信息记录不一致问题，新冠后遗症的实际患病率可能更高。操作定义提供了一种新方法，但依赖于一组有限的症状，可能会对已有健康状况的个体进行错误分类。需要进一步研究来完善和验证这种方法。
首席科学家办公室（苏格兰）、医学研究理事会和BREATHE。
