Strålin Kristoffer, Wahlström Erik, Walther Sten, Bennet-Bark Anna M, Heurgren Mona, Lindén Thomas, Holm Johanna, Hanberger Håkan
Department of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden.
Department of Medicine, Huddinge, Karolinska Institutet, Stockholm, Sweden.
Lancet Reg Health Eur. 2021 May;4:100054. doi: 10.1016/j.lanepe.2021.100054. Epub 2021 Feb 26.
It is important to know if mortality among hospitalised COVID-19 patients has changed as the pandemic has progressed. The aim of this study was to describe the dynamics over time of mortality among patients hospitalised for COVID-19 in Sweden, using nationwide data compiled by the Swedish National Board of Health and Welfare.
Observational cohort study where all patients hospitalised in Sweden between March 1 and September 30, 2020, with SARS-CoV-2 RNA positivity 14 days before to 5 days after admission and a discharge code for COVID-19 were included. Outcome was 60-day all-cause mortality. Patients were categorised according to month of hospital admission. Poisson regression was used to estimate the relative risk of death by month of admission, adjusting for, age, sex, comorbidities, care dependency, country of birth, healthcare region, and Simplified Acute Physiology, version 3 (patients in intensive care units; ICU).
A total of 17,140 patients were included, of which 2943 died within 60 days of admission. The overall 60-day mortality was thus 17·2% (95% CI, 16·6%-17·7%), and it decreased from 24·7% (95% CI, 23·0%-26·5%) in March to 10·4% (95% CI, 8·9%-12·1%) post-wave (July-September). Adjusted relative risk (RR) of death was 0·46 (95% CI, 0·39-0·54) post-wave, using March as reference. Corresponding RR for patients not admitted to ICU and those admitted to ICU were 0·49 (95% CI, 0·42-0·59) and 0·49 (95% CI, 0·33-0·72), respectively. The proportion of patients admitted to ICU decreased from 19·4% (95% CI, 17·9%-21·1%) in the March cohort to 8·9% (95% CI, 7·5%-10·6%) post-wave.
There was a gradual decline in mortality during the spring of 2020 in Swedish hospitalised COVID-19 patients, independent of baseline patient characteristics. Future research is needed to explain the reasons for this decline. The changing COVID-19 mortality should be taken into account when management and results of studies from the first pandemic wave are evaluated.
This study was funded by Sweden's National Board of Health and Welfare.
了解随着新冠疫情的发展，住院新冠患者的死亡率是否发生变化很重要。本研究的目的是利用瑞典国家卫生与福利委员会汇编的全国性数据，描述瑞典因新冠住院患者死亡率随时间的动态变化。
观察性队列研究，纳入2020年3月1日至9月30日期间在瑞典住院的所有患者，这些患者在入院前14天至入院后5天SARS-CoV-2 RNA呈阳性，且有新冠出院诊断代码。观察指标为60天全因死亡率。患者按入院月份分类。采用泊松回归估计按入院月份划分的死亡相对风险，并对年龄、性别、合并症、护理依赖程度、出生国家、医疗区域和简化急性生理学评分第3版（重症监护病房患者）进行调整。
共纳入17140例患者，其中2943例在入院60天内死亡。因此，总体60天死亡率为17.2%（95%置信区间，16.6%-17.7%），从3月的24.7%（95%置信区间，23.0%-26.5%）降至疫情高峰后（7月至9月）的10.4%（95%置信区间，8.9%-12.1%）。以3月为参照，疫情高峰后调整后的死亡相对风险（RR）为0.46（95%置信区间，0.39-0.54）。未入住重症监护病房患者和入住重症监护病房患者的相应RR分别为0.49（95%置信区间，0.42-0.59）和0.49（95%置信区间，0.33-0.72）。入住重症监护病房的患者比例从3月队列中的19.4%（95%置信区间，17.9%-21.1%）降至疫情高峰后8.9%（95%置信区间，7.5%-10.6%）。
2020年春季，瑞典住院新冠患者的死亡率逐渐下降，与患者基线特征无关。需要进一步研究来解释死亡率下降的原因。在评估第一波疫情期间的研究管理和结果时，应考虑新冠死亡率的变化。
本研究由瑞典国家卫生与福利委员会资助。
