Table 3

Characteristics of included studies

StudyStudy designCountry/
Intervention(s) descriptionInclusion criteriaConfounders (variables, how measured)Analysis methodOutcomes of interestTotal participants (n)
Seeland et al, 202020 Retrospective database cohortDerived from electronic health records of multiple healthcare organisations across 17 countriesHormone use: estradiol and CHC.
Hormone use was identified via RxNorm codes 4083 (estradiol), 4124 (ethinyl estradiol), progestins VA:HS800, and systemic contraceptives VA:HS200
Pre-menopausal women aged 15–49 who were COVID-19-positive in the last 7 monthsTriNetX analytics tools were used to assess baseline characteristics including ‘demographics, diagnoses, procedures, and medication’.
No information on exactly which variables were collected or how they were measured
A logistic regression analysis was performed for the combined outcome variable ‘death’ incorporating the propensity score matchingMortalityn=18 892
Mujumdar et al, 202021 Retrospective database cohortTertiary medical centre in the USAHormonal contraception including levonorgestrel-intrauterine device, progestin-only pills, CHC, and injectable progestin reported in medical chartReproductive age women ages 12–49 who tested COVID-19-positiveUncertainLogistic regressionHospitalisation.
n=123 COVID-19-positive patients
Costeira et al, 202122 Prospective cohort studyUsers of the application in
the UK
Combined hormonal oral contraceptive use (self-report)Female app users aged 20–45 with BMI between 18–35 kg/m2 Age, BMI, smoking status (self-reported)Binomial generalised mixed models with a log-odds/logit link function used for association
Age: continuous fixed effect.
BMI: continuous fixed effect.
Smoker: categorical fixed effect – never, former, and current.
Sensitivity analyses performed to match the mean and median age of cases and controls for the exposure variables in subsets of users in 5-year age bins
Hospitalisationn=295 689
Chima et al, 202123 Case series41 healthcare organisations participating in TriNetX - data for 8 patients in the USACHC
Case definition: pulmonary embolism: defined using any ICD-10 root diagnostic code; medications 30 days before and after acute PE diagnosis and COVID-19 diagnosis
Paediatric patients <18 years old with PE and COVID-19-positive. PE diagnosed concurrently or within 30 days of COVID-19 diagnosisAge, BMI, race, ethnicity, lab results, medicationsDescriptivePulmonary embolismn=6 girls
Hameed et al, 202124 Case seriesMulticentre multinational study – 10 tertiary care centres in Pakistan, Egypt, Singapore, and the USA‘Oral contraception’
CVT case definition: ‘Diagnosis of CVT was confirmed by at least one of the following imaging studies according to the established criteria: MR imaging, MR venography, CT, CT venography, or cerebral venography
Patients aged 18 or older with ‘recent COVID-19 infection, confirmed either by reverse transcriptase-polymerase chain reaction assay of a nasopharyngeal swab or serum antibody testing for COVID-19’‘Risk factors, clinical features, laboratory findings, imaging findings, COVID-19-related information’Descriptive: frequencies and correlationsCerebral venous thrombosisn=7 women with CVT
  • BMI, body mass index; CHC, combined hormonal contraception; CVT, cerebral venous thromboembolism; ICD-10, International Classification of Diseases, 10th revision; PE, pulmonary embolism.