Table 1. Characteristics of included studies.
| Author | Country | Language | Design | Diagnosis | N(H)CQ/Ctl | HCQ/CQ regimen | Counterpart regimen | Age | M/F | Severity | Baseline imbalance | Methodological weakness led to high risk of bias |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Randomized controlled trials | ||||||||||||
| Chen J | China | Chinese | Open RCT | PCR | 15/15 | HCQ 400 mg qd, d1–5 | None | 48.6 | 21/9 | Unclear | None | Not blinded |
| Chen Z | China | English | RCT | rtPCR | 31/31 | HCQ 200 mg bid, d1–5 | None | 44.7 | 29/33 | Mild, pneumonia | None | No description of blinding |
| Huang | China | English | RCT | rtPCR | 10/12 | CQ 500 mg bid, d1–10 | Lopinavir/ritonavir 400/100 mg bid d1–10 | 44 | 13/9 | Moderate 14, severe 8 | Earlier treatment in CQ arm (2.5 vs. 6.5 d, P<0.001) | No description of blinding; not registered; baseline imbalance |
| Tang | China | English | Open RCT | Real time rtPCR | 75/75 | HCQ 1,200 mg d1–3; 800 mg d4–21 | None | 46.1 | 82/68 | Mild/moderate 148, severe 2 | None | Not blinded |
| Observational studies | ||||||||||||
| Chen X | China | English | Retro obs | Real time rtPCR | 17/121 | CQ dose unspecified | None | Apx 48 | Apx 54%/46% | Moderate or less: apx 84%, serious/critical: apx 16% | Unclear | Not registered retrospective design; inconsistent CQ dosage; not adjusted for covariate; lack of basal data in each arm |
| Gautret | France | English | Pro obs | Real time rtPCR | 26/16 | HCQ 200 mg tid (+AZM 500 mg d1, 250 mg d2–; 6 patient) | None | Apx 45.1 | Apx 42%/58% | Unclear | Elder in HCQ arm (mean 51 vs. 37 yo, P=0.06) | Attenuation in HCQ arm; less recruited than protocol; inconsistent addition of azm; baseline imbalance; not adjusted for covariate |
| Rosenberg | USA | English | Retro obs | Laboratory confirmed | 735/271/ 211/221 | HCQ + AZM/HCQ/AZM/neither, dose unspecified | Four-arm factorial design | Apx 60 | 858/580 | Unclear | HCQ + AZM and HCQ were more frequently used for shock and oxygen desaturation cases | Not registered retrospective design; inconsistent CQ dosage; baseline imbalance |
| Mahevas | France | English | Retro obs, propensity score | PCR | 84/97 | HCQ 600 mg/d | None | 60 | 128/33 | Moderate (O2, not ICU), Pneumonia | None | Not registered retrospective design |
Age: median or mean age. Apx: approximately, exact data were unclear because Chen et al. aggregated data including cases who were treated with other antiviral drugs and because Gautret et al. presented data after excluding lost cases. RCT, randomized controlled trial; pro obs, prospective observational study; retro obs, retrospective observational study; rtPCR, reverse transcription PCR; N(H)CQ/Ctl, numbers of patients in HCQ/CQ arm and control arm; CQ, chloroquine; HCQ, hydroxychloroquine; AZM, azithromycin; M/F, male female ratio.