PubMed Central, : RMMJ Rambam Maimonides Medical Journal Rambam Health Care Campus 2020 July; 11(3): e0025. ISSN: 2076-9172Published online 2020 July 31. doi: 10.5041/RMMJ.10416.

Study Design	Pts	Study Groups	Results: Primary/Secondary^* Outcomes	Methodological Issues
Comparative multinational registry analysis²⁹	96,032	1. CQ 2. CQ+macrolide 3. HCQ 4. HCQ+macrolide 5. SOC	Primary Outcome Significant ↑ of in-hospital mortality rates for CQ (16.4%); CQ+macrolide (22.2%); HCQ (18.0%); HCQ+macrolide (23.8%); vs SOC (9.3%) Secondary Outcome All Tx groups independently associated with ↑ risk of de novo ventricular arrhythmia during hospitalization	Publication retracted as per request of three co-authors The corporation that initially provided the Pt dataset refused to transfer the full dataset, client contracts, and ISO audit reports for re-analysis
Comparative observational study²⁶	42	1. HCQ 2. SOC	Sig.Dif. in virological cure rates between HCQ (70%) and SOC (12.5%) groups (P=0.001)	Selection bias: SOC group comprised Pts who refused HCQ Tx Failure to follow-up Pts for adequate post-treatment periods Age difference between HCQ and SOC groups: mean age 51.2 years vs 37.3 years, respectively (P=0.06) Unclear exclusion criteria for HCQ group 5 SOC Pts with no virological test on day 6 were included in the final analysis as COVID-19-positive cases
Re-analysis of study,²⁶ including the missing datasets²⁷	42	1. HCQ 2. SOC	No significant differences in virological cure rates on treatment days 3, 4, 5, or 6^*	None. Study refers to methodological problems of the abovementioned study
Uncontrolled observational study²⁸ aimed at replicating the above comparative observational study²⁶	11	1. HCQ	20% of patients were virologically cured at day 5–6 post-inclusion^*

^*Only primary outcomes are shown, unless the study also provided secondary outcomes.

↑, increased/higher; CQ, chloroquine; ISO, International Organization for Standardization; HCQ, hydroxychloroquine; Pt(s), patient(s); RT-qPCR, reverse transcription polymerase chain reaction; Sig.Dif., significant difference(s); SOC, standard of care; Tx, treatment.