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Short Report| Volume 53, 103613, February 2023

COVID-19 infection and maternal morbidity in critical care units in Scotland: a national cohort study

Open AccessPublished:December 01, 2022DOI:https://doi.org/10.1016/j.ijoa.2022.103613

      Highlights

      • Outcomes of women in critical care with COVID-19 are under-reported.
      • Less than 5% of this national cohort had received any form of vaccination.
      • 12% needed an emergency non-obstetric hospital re-admission within 90 days.

      Abstract

      Background

      Previous research has shown that, in comparison with non-pregnant women of reproductive age, pregnant women with COVID-19 are more likely to be admitted to critical care, receive invasive ventilation, and die. At present there are limited data in relation to outcomes and healthcare utilisation following hospital discharge of pregnant and recently pregnant women admitted to critical care.

      Methods

      A national cohort study of pregnant and recently pregnant women who were admitted to critical care in Scotland with confirmed or suspected COVID-19. We examined hospital outcomes as well as hospital re-admission rates.

      Results

      Between March 2020 and March 2022, 75 pregnant or recently pregnant women with laboratory-confirmed COVID-19 were admitted to 24 Intensive Care Units across Scotland. Almost two thirds (n=49, 65%) were from the most deprived socio-economic areas. Complete 90-day acute hospital re-admission data were available for 74 (99%) patients. Nine (12%) women required an emergency non-obstetric hospital re-admission within 90 days. Less than 5% of the cohort had received any form of vaccination.

      Conclusions

      This national cohort study has demonstrated that pregnant or recently pregnant women admitted to critical care with COVID-19 were more likely to reside in areas of socio-economic deprivation, and fewer than 5% of the cohort had received any form of vaccination. More targeted public health campaigning across the socio-economic gradient is urgently required.

      Keywords

      Introduction

      Risk factors for the development of severe COVID-19 disease such as multimorbidity, socio-economic deprivation, ethnicity and age, are well established.
      • Lone N.I.
      • McPeake J.M.
      • Stewart N.I.
      • et al.
      Influence of socioeconomic deprivation on interventions and outcomes for patients admitted with COVID-19 to critical care units in Scotland: A national cohort study.
      • Richardson S.
      • Hirsch J.B.
      • Narasimham D.O.
      • et al.
      Presenting characteristic, comorbidities and outcomes among 5700 patients hospitalised with COVID-19 in the New York City area.
      Ongoing research has also shown that, in comparison with non-pregnant women of reproductive age, pregnant women with COVID-19 are more likely to be admitted to critical care, receive invasive ventilation, and die.
      • Stock S.J.
      • Carruthers J.
      • Calvert C.
      • et al.
      SARS-CoV-2 infection and COVID-19 vaccination rates in pregnant women in Scotland.
      • Allotey J.
      • Fernandez S.
      • Bonet M.
      • et al.
      Clinical manifestations, risk factors, and maternal and perinatal outcomes of coronavirus disease 2019 in pregnancy: living systematic review and meta-analysis.
      Despite this, the clinical course of pregnant and recently pregnant women admitted to critical care warrants further investigation, especially in relation to hospital outcomes and healthcare utilisation following hospital discharge.
      To understand the care trajectory of this patient group, we report a complete national cohort of pregnant and recently pregnant women admitted to critical care in Scotland with confirmed or suspected COVID-19. Uniquely, we also examined re-admission rates in the 90 days following hospital discharge.

      Methods

      The Scottish Intensive Care Audit Group (SICSAG) received approval by the Public Benefit and Privacy Panel for Health and Social Care (1920-0093) to undertake work relating to the COVID-19 pandemic.
      Data sources were linked via the Community Health Index number, a unique patient identifier. This linkage included: the Scottish Morbidity Record (SMR) 01 which captures acute, non-obstetric hospital activity; the Electronic Communication of Surveillance in Scotland which captures virology testing; the National Records of Scotland death records; and the SICSAG database. The SICSAG database prospectively captures all adult intensive care unit (ICU) and general high dependency unit (HDU) activity within Scotland, including pregnancy status on admission, and is subject to regular validation assessments.
      Using a cohort study design, we examined patients aged 16 years or older, admitted to Scottish critical care units, who were pregnant or recently pregnant (within six weeks of delivery), with a positive polymerase chain reaction test for nucleic acid for SARS CoV-2 before or during critical care admission.
      Demographic and acute illness variables were obtained from the SICSAG dataset. Ethnicity was derived from categories of the Scottish Census (2011) with low frequencies aggregated. Socio-economic deprivation was defined using quintiles of the Scottish Index of Multiple Deprivation (SIMD), which is an area-based ranking index based on postcode of residence.

      Scottish Government. Scottish Index of Multiple Deprivation 2020. Available from https://www.gov.scot/collections/scottish-index-of-multiple-deprivation-2020/. Accessed 16 April, 2022.

      Vaccination status was categorised as: one dose, two or more doses, or unvaccinated. We divided time periods into ‘waves’ of COVID-19 critical care admissions, which were defined by Public Health Scotland: Wave 1 from 1 March, 2020 to 31 July, 2020; Wave 2 from 1 August, 2020 to 18 May, 2021; Wave 3 from 19 May, 2021 to 13 March, 2022.

      Public Health Scotland (2022) Scottish Intensive Care Society Audit Group report on COVID-19. As at 11th of January 2022. https://publichealthscotland.scot/media/11407/2022-02-02_sicsag_report.pdf. Accessed 16 April, 2022.

      We included waves in our descriptive analysis as these reflect the different predominant variants of SARS CoV-2 during the time period.

      Public Health Scotland (2022) Scottish Intensive Care Society Audit Group report on COVID-19. As at 11th of January 2022. https://publichealthscotland.scot/media/11407/2022-02-02_sicsag_report.pdf. Accessed 16 April, 2022.

      Data were analysed using R version 3.6.1 (R Core Team (2018)).

      Results

      Between March 2020 and March 2022, 75 pregnant or recently pregnant women with laboratory-confirmed COVID-19 were admitted to 24 ICUs across Scotland. The majority of women (n=51, 68%) were admitted during the third pandemic ‘wave’ (Fig. 1).
      Figure thumbnail gr1
      Fig. 1Number of admissions of pregnant or recently pregnant patients with COVID-19 disease to Scottish Critical Care units by month, stratified by ‘wave’. Waves are defined as: Wave 1 from 1 March, 2020 to 31 July, 2020; Wave 2 from 1 August, 2020 to 18 May, 2021; Wave 3 from 19 May, 2021 to 13 March, 2022. May 2021 therefore incorporates the end of Wave 2 and beginning of Wave 3
      The median age of the cohort was 31 (interquartile range (IQR) 27.5–35) years and almost two thirds (n=49, 65%) were from the most deprived socio-economic geographical areas (SIMD 1 and 2). Across the cohort, 48 (64%) women were pregnant on admission to ICU and 27 (36%) were within six weeks of delivery. Less than 5% of the cohort had received any form of vaccination. In total, nine (12%) patients had a recorded comorbidity on admission (Table 1).
      Table 1Demographics and outcomes of cohort
      Characteristicn=75
      Age, years (median, IQR)31 (27.5–35)
      Pregnancy status on admission:
        - Antenatal48 (64.0%)
        - Postnatal27 (36.0%)
      Socio-economic status quintile (SIMD)
        - 1 (most deprived)31 (41.3%)
        - 218 (24.0%)
        - 312 (16.0%)
        - 49 (12.0%)
        - 5 (least deprived)5 (6.7%)
      Vaccination status on admission
        - One dose1 (1.3%)
        - Two or more doses1 (1.3%)
        - Unvaccinated73 (97.3%)
      Admission diagnosis
        - COVID-19 confirmed chest infection/viral chest infection57 (76%)
        - Other18 (24%)
      Ethnicity
        - White58 (79.5%)
        - Black/Caribbean/African4 (5.5%)
        - Asian8 (11.0%)
        - Other3 (4.1%)
        - Missing2 (2.7%)
      Count of previous comorbidity
      SICSAG-defined severe comorbidities were combined with Charlson-defined comorbidities in order to report the most prevalent comorbidities.
        - 066 (88.0%)
        - 1 or more9 (12.0%)
      Admission wave
        - Wave 12 (2.7%)
        - Wave 222 (29.3%)
        - Wave 351 (68.0%)
      Critical care length of stay, days (median, IQR)4 (1.5–9)
      Total hospital length of stay, days (median, IQR)10 (6–17)
      Requirement for advanced respiratory support33 (44.0%)
      Requirement for non-invasive respiratory support44 (58.7%)
      Requirement for non-invasive and invasive respiratory support19 (25.3%)
      Duration of advanced respiratory support, days (median, IQR)5 (2–10)
      Requirement for cardiovascular support24 (32.0%)
      Duration of cardiovascular support, days (median, IQR)2.5 (2.8–5)
      Requirement for renal replacement therapy1 (1.3%)
      Hospital mortality1 (1.3%)
      Emergency hospital re-admission for non-obstetric causes (n=74)
        - within 30 days7 (9.5%)
        - within 60 days8 (10.8)
        - within 90 days9 (12.2%)
      * SICSAG-defined severe comorbidities were combined with Charlson-defined comorbidities in order to report the most prevalent comorbidities.
      The median critical care length of stay (LOS) was 4 (IQR 1.5–9) days and median hospital LOS was 10 (IQR 6–17) days. Advanced respiratory support was required by 33 (44%) patients, while non-invasive support was required by 44 (59%) and one quarter (n=19, 25%) required a combination of both types of respiratory support. Almost one third (n=24, 32%) required cardiovascular support. Ultimate hospital mortality was 1.3% (n=1).
      Complete 90-day, acute hospital re-admission data were available for 74 (99%) patients. Nine (12%) women required an emergency non-obstetric hospital re-admission within 90 days.

      Discussion

      This complete national cohort of pregnant or recently pregnant women admitted to critical care with COVID-19 has shown a high need for organ support and a non-obstetric re-admission rate of 12%. Despite significant public health campaigning around the benefits of vaccination, vaccination rates were low in this cohort.
      Less than 5% of this cohort had been vaccinated, findings which support the vital role that vaccination plays in pregnancy. Urgent public health attention is required to inform people of the benefits of vaccination and the significant impact that severe COVID-19 can have on the entire family unit. Moreover, future clinical trials which investigate vaccinations must explicitly include pregnant women to ensure that women can benefit fully from potentially life-saving treatments.
      • Knight M.
      • Morris R.K.
      • Furniss J.
      • et al.
      Include pregnant women in research- particularly COVID-19 research.
      Nearly two thirds of the cohort were from areas of socio-economic deprivation. This is higher than that reported for an unselected non-pregnant cohort, where fewer than half of the population were from areas of socio-economic deprivation.
      • Lone N.I.
      • McPeake J.M.
      • Stewart N.I.
      • et al.
      Influence of socioeconomic deprivation on interventions and outcomes for patients admitted with COVID-19 to critical care units in Scotland: A national cohort study.
      Lower levels of vaccination uptake have been associated with socio-economic position.
      • Dolby T.
      • Finning K.
      • Baker A.
      • et al.
      Monitoring sociodemographic inequality in COVID-19 vaccination uptake in England: a national linked data study.
      More targeted public health campaigning across the socio-economic gradient is urgently required.
      Following discharge, one in eight women in this cohort experienced an emergency re-admission in the 90 days following hospital discharge. Although this re-admission rate was lower than that of the wider critical care COVID-19 cohort in Scotland (16%) and other critical care cohorts, these non-maternity cohorts are older and have a higher prevalence of comorbidity.
      • McPeake J.
      • Bateson M.
      • Christies F.
      • et al.
      Hospital readmission after critical care survival: a systematic review and meta-analysis.
      Previous research has demonstrated that those most at risk of re-admission following critical illness are likely to be those survivors with established frailty or complex comorbidity, a distinctly different group from this current cohort.
      • McPeake J.
      • Bateson M.
      • Christies F.
      • et al.
      Hospital readmission after critical care survival: a systematic review and meta-analysis.
      This analysis was unable to delineate reasons for re-admission, so future research should seek to understand the causes of re-admission in this cohort.
      In parallel with understanding the medical management of this cohort, it is also essential that psychological sequelae are addressed. It is well known that patients can have psychological problems such as anxiety and post-traumatic stress symptomology following a critical illness and following a pregnancy complicated by severe morbidity.
      • Wade D.
      • Howell D.
      • Weinman A.
      • et al.
      Investigating risk factors for psychological morbidity three months after intensive care: a prospective cohort study.
      • Hinton L.
      • Locock L.
      • Knight M.
      Maternal critical care: what can we learn from patient experience? A qualitative study.
      Well-established psychological interventions in pregnancy or the postpartum period may not have been available for this cohort due to the nature of their illness, which may worsen these psychological issues further. Clinicians should ensure that patients have access to rehabilitation services across the recovery trajectory.
      The strengths of our study include the complete, nationwide capture of critically ill pregnant or recently pregnant women with COVID-19, and the ability to report hospital re-admission. Limitations include being unable to report more person-centred outcomes, such as psychological sequelae, and neonatal outcomes. Moreover, we do not have data on why women were re-admitted to hospital or which women gave birth during their critical care admission. Finally, this cohort lacks a comparator cohort, and as such we are unable to determine if the problems described were unique to the pregnant or recently pregnant cohort.
      This national cohort study has demonstrated that pregnant or recently pregnant women admitted to critical care with COVID-19 were more likely to reside in areas of socio-economic deprivation and that <5% of the cohort had received any form of vaccination. More targeted public health campaigning across the socio-economic gradient is urgently required.

      Declaration of interests

      JM is supported by a University of Cambridge (The Healthcare Improvement Studies Institute). Research Fellowship (PD-2019-02-16).

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