Filling the gaps in the characterization of the clinical management of COVID-19: 30-day hospital admission and fatality rates in a cohort of 118 150 cases diagnosed in outpatient settings in Spain

  1. Daniel Prieto-Alhambra
  2. Elisabet Balló
  3. Ermengol Coma
  4. Núria Mora
  5. María Aragón
  6. Albert Prats-Uribe
  7. Francesc Fina
  8. Mència Benítez
  9. Carolina Guiriguet
  10. Mireia Fàbregas
  11. Manuel Medina-Peralta
  12. Talita Duarte-Salles

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Abstract

Background

Currently, there is a missing link in the natural history of COVID-19, from first (usually milder) symptoms to hospitalization and/or death. To fill in this gap, we characterized COVID-19 patients at the time at which they were diagnosed in outpatient settings and estimated 30-day hospital admission and fatality rates.

Methods

This was a population-based cohort study.

 

Data were obtained from Information System for Research in Primary Care (SIDIAP)—a primary-care records database covering >6 million people (>80% of the population of Catalonia), linked to COVID-19 reverse transcriptase polymerase chain reaction (RT-PCR) tests and hospital emergency, inpatient and mortality registers. We included all patients in the database who were ≥15 years old and diagnosed with COVID-19 in outpatient settings between 15 March and 24 April 2020 (10 April for outcome studies). Baseline characteristics included socio-demographics, co-morbidity and previous drug use at the time of diagnosis, and polymerase chain reaction (PCR) testing and results.

 

Study outcomes included 30-day hospitalization for COVID-19 and all-cause fatality.

Results

We identified 118 150 and 95 467 COVID-19 patients for characterization and outcome studies, respectively. Most were women (58.7%) and young-to-middle-aged (e.g. 21.1% were 45–54 years old). Of the 44 575 who were tested with PCR, 32 723 (73.4%) tested positive. In the month after diagnosis, 14.8% (14.6–15.0) were hospitalized, with a greater proportion of men and older people, peaking at age 75–84 years. Thirty-day fatality was 3.5% (95% confidence interval: 3.4% to 3.6%), higher in men, increasing with age and highest in those residing in nursing homes [24.5% (23.4% to 25.6%)].

Conclusion

COVID-19 infections were widespread in the community, including all age–sex strata. However, severe forms of the disease clustered in older men and nursing-home residents. Although initially managed in outpatient settings, 15% of cases required hospitalization and 4% died within a month of first symptoms. These data are instrumental for designing deconfinement strategies and will inform healthcare planning and hospital-bed allocation in current and future COVID-19 outbreaks.

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  1. Version published to 10.1093/ije/dyaa190
  2. ScreenIT

    SciScore for 10.1101/2020.05.04.20090050: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    Institutional Review Board Statementnot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    A pre-specified list of medicines was created based on the same previous literature3–5, and identified using ATC codes (Supplementary Table 2). Outcomes: Both study outcomes were studied in the 30 days after index date.
    ATC
    suggested: None

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    Our study has a number of limitations. First, the use of routinely collected data allowed for the inclusion of a large number of participants, but misclassification is possible as other flu-like or respiratory conditions could potentially be diagnosed as COVID-19 in the context of the current pandemic. However, SIDIAP is a well validated data source9 with many previous studies conducted24. In a subsample with RT-PCR data available, almost 3 in 4 cases were positive, suggesting that the positive predictive value of primary care diagnosis in our context approached 75%. Given that the other 1 in 4 had better health outcomes (less hospitalizations and lower fatality), it is likely that this misclassification has led to an underestimation of the risk of complications, admissions, and fatality related to COVID-19 infection in our study. Secondly, although we include milder forms of COVID-19 than previous characterisation studies, it is still likely that asymptomatic and cases with little symptoms were advised to stay home and self-isolate to avoid contact and spread in healthcare facilities including primary care practices and hospitals. This study also has many strengths. The use of primary care records linked to hospital, mortality and testing registers obtained from a universal tax-funded healthcare system allowed for a complete characterisation of the natural history of COVID-19 infection from symptom onset. In addition, the inclusion of COVID-19 cases treated exclusively in ou...

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    About SciScore

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  3. Version published to 10.1101/2020.05.04.20090050v1 on medRxiv