Table 1.
Basic characteristics of the included studies.
| Author | Year | Country | Study type | Data source | Sample size, n | Follow-up duration, months | Mean age, years | Diagnosis of COVID-19/diabetes | Diabetes type | Interval, days | NOS scores | Adjusted factors |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Aslam et al. (23) | 2023 | Pakistan | Retrospective cohort | Department of respiratory physiology and medicine of independent University Hospital | COVID: 55 Control: 50 |
5 | COVID: 39.5 Control: 25.65 |
COVID: medical records, RT-PCR Diabetes: medical records, HbA1c |
T2D | >1 | 7 | NR |
| Barrett et al. (24)[1] | 2022 | USA | Retrospective cohort | IQVIA | COVID: 80,893 Control: 404,465 |
12 | COVID: 12.3 Control: 12.3 |
COVID: medical records, ICD-10 Diabetes: medical records, ICD-10 |
T1D/T2D | >30 | 8 | Age, sex |
| Barrett et al. (24)[2] | 2022 | USA | Retrospective cohort | Health Verity | COVID: 439,439 Control: 439,439 |
16 | COVID: 12.7 Control: 12.7 |
COVID: medical records, PCR, ICD-10 Diabetes: medical records, ICD-10 |
T1D/T2D | >30 | 8 | Age, sex |
| Bowe et al. (21) | 2022 | USA | Retrospective cohort | VHSUS Veterans Health Administration | COVID: 234,990 Control: 5,334,729 |
27.8 | COVID: 60.12 Control: 60.12 |
COVID: medical records, RT-PCR, ICD-10 Diabetes: medical records, HbA1c, ICD-10 |
T2D | >1 | 6 | Age, sex, race, BMI, vaccination status, area deprivation index, smoking |
| Choi et al. (25) | 2023 | South Korea | Retrospective cohort | Health Insurance Review and Assessment Service | COVID: 348,180 Control: 1,044,540 |
12.5 | COVID: 43.3 Control: 43.3 |
COVID: medical records, ICD-10 Diabetes: medical records, ICD-10 |
T2D | >30 | 9 | Age, sex, hypertension, dyslipidemia |
| Daugherty et al. (26) | 2021 | USA | Retrospective cohort | United Health Group Clinical Discovery Database | COVID: 266,586 Control: 8,980,919 |
10 | COVID: 41.7 Control: 42.4 |
COVID: medical records, PCR, ICD-10 Diabetes: medical records, ICD-10 |
T2D | >21 | 7 | Age, sex, race |
| Jun Zhang et al. (27) | 2022 | China | Prospective cohort | Wuhan Hospital of Traditional Chinese Medicine | COVID: 171 Control: 77 |
3.3 | Total: 61.0 | COVID: medical records, RT-PCR Diabetes: fasting blood glucose |
T1D/T2D | After discharge | 7 | Age, sex, BMI, smoking, drinking, hypertension, comorbidities |
| Kendall et al. (28) | 2022 | USA | Retrospective cohort | TriNetX | COVID: 314,917 Control: 776,577 |
6 | COVID: 10.3 Control: 10.3 |
COVID: medical records, ICD-10 Diabetes: NR |
T1D | >1 | 7 | NR |
| Kwan et al. (29) | 2023 | USA | Retrospective cohort | Cedars-Sinai Health System | Total: 23,709 | 6 | Total: 47.4 | COVID: medical records, ICD-9, ICD-10 Diabetes: medical records, ICD-9, ICD-10 |
T1D/T2D | 0-90 | 6 | Age, sex, hypertension, hyperlipidaemia |
| Lu et al. (30) | 2023 | USA | Retrospective cohort | Montefiore Health System in Bron | COVID: 19,427 Control: 5,730 |
3 | NR | COVID: medical records, RT-PCR Diabetes: medical records, ICD-10 |
T2D | >1 | 9 | Age, sex, race, ethnicity, BMI, hypertension, HF, CKD, COPD |
| McKeigue et al. (31) | 2022 | UK | Retrospective cohort | REACT-SCOT | COVID: 365,080 Control: 1,484,331 |
20.6 | Range: <35 | COVID: medical records, PCR Diabetes: medical records |
T1D | >1 | 9 | Sex, vaccination status |
| Naveed et al. (32) | 2023 | Canada | Retrospective cohort | British Columbia COVID-19 Cohort | COVID: 125.987 Control: 503,948 |
24 | COVID: 45 Control: 41.5 |
COVID: medical records, RT-PCR Diabetes: medical records, ICD-9, ICD-10 |
T1D/T2D | >30 | 7 | Age, sex, vaccination status |
| Noorzae et al. (33) | 2023 | Denmark | Retrospective cohort | The Danish Civil Registration System | COVID: 419,260 Control: 1,174,677 |
30 | Range: 0-17 | COVID: medical records Diabetes: medical records, ICD-10 |
T1D | >30 | 7 | Age, sex, comorbidities, vaccination status |
| Qeadan et al. (34) | 2022 | USA | Retrospective cohort | Cerner Real-World Data | COVID: 2,489,266 Control: 24,803,613 |
22 | COVID: 44.5 Control: 41.1 |
COVID: medical records, laboratory test Diabetes: medical records, ICD-10 |
T1D | >1 | 6 | Age, sex, race, ethnicity, marital status, region |
| Rathmann et al. (35) | 2022 | Germany | Retrospective cohort | Disease Analyzer | COVID: 35,865 Control: 35,865 |
16.7 | COVID: 42.6 Control: 42.6 |
COVID: medical records, ICD-10 Diabetes: medical records, ICD-10 |
T2D | >1 | 9 | Age, sex, obesity, hypertension, hyperlipidemia |
| Rege et al. (36) | 2023 | Israel | Retrospective cohort | Clalit | COVID: 157,936 Control: 157,936 |
10.9 | COVID: 43 Control: 43 |
COVID: medical records, PCR Diabetes: medical records, ICD-9 |
T1D/T2D | >1 | 9 | Age, BMI, socioeconomic status, hypertension, dyslipidemia, smoking status |
| Rezel-Potts et al. (37) | 2022 | UK | Retrospective cohort | CPRD Aurum | COVID: 428,650 Control: 428,650 |
12 | COVID: 35 Control: 35 |
COVID: medical records, PCR Diabetes: medical records, HbA1c |
T1D/T2D | 0-120 | 9 | Age, sex, ethnicity, BMI, smoking status |
| Soysal and Yilmaz (38) | 2022 | Turkey | Retrospective cohort | Obstetrics outpatient clinic of the Obstetrics and Gynecology Department of Ankara | COVID: 150 Control: 150 |
27 | COVID: 28.73 Control: 28.29 |
COVID: medical records Diabetes: medical records, OGTT |
GDM | >1 | 9 | NR |
| Xie and Al-Aly (22) | 2022 | USA | Retrospective cohort | VHA | COVID: 181,280 Control: 4,278,701 |
11.6 | COVID: 60.9 Control: 61.5 |
COVID: medical records, laboratory test Diabetes: medical records, ICD-10 |
T2D | >30 | 6 | Age, sex, race, area deprivation index, BMI, smoking status, comorbidities |
| Yongkang Zhang et al. (39) | 2022 | USA | Retrospective cohort | PCORnet | COVID: 316,249 Control: 2,775,331 |
3 | Non-hospitalized COVID: 48.9 Hospitalized COVID: 59.9 Non-hospitalized control: 52.8 Hospitalized control: 55.9 |
COVID: medical records, PCR, lCD-10 Diabetes: medical records, ICD-10 |
T1D/T2D | 31-150 | 6 | Age, sex, race, BMI, ethnicity, smoking status, comorbidities |
| Zareini et al. (17) | 2023 | Denmark | Retrospective cohort | Danish National Patient Registry; Danish National Prescription Registry; The Danish Cause of Death Registry; Danish Population Registry Danish Microbiology Database | COVID: 338,670 Control: 1,004,688 |
84 | Total: 12.8 | COVID: medical records, PCR Diabetes: medical records |
T1D | >1 | 9 | Age, sex, vaccination status |
T1D, type 1 diabetes; T2D, type 2 diabetes; GDM, gestational diabetes mellitus; PCR, polymerase chain reaction; RT-PCR, reverse transcription polymerase chain reaction; ICD-10, International Classification of Diseases 10th Revision; ICD-9, International Classification of Diseases 9th Revision; BMI, body mass index; OGTT, oral glucose tolerance test; HF, heart failure; CKD, chronic kidney diseases; COPD, chronic obstructive pulmonary disease; NR, not reported.