A systematic review and meta-analysis on virological and clinical cure in patients treated with hydroxychloroquine (HCQ) for COVID-19

HCQ treatment was found to be beneficial in terms of reducing the number of COVID-19 patients with radiological progression with no rise in the rate of adverse effects compared to the control group.

WHO has declared coronavirus disease or COVID-19, a global pandemic. But, to date, there is no availability of the treatment options for this deadly disease. The worldwide increase in the number of infected cases and deaths has generated an urgent need to look for safe and effective treatment strategies for COVID-19. Lopinavir/ritonavir has been initially used for disease management in the first place, but a recent study by Cao et al. demonstrated no significant benefit in primary endpoint when lopinavir/ritonavir was compared with the standard of care. On the other hand, chloroquine (CQ) has emerged as a potential treatment for COVID-19 as it has shown to inhibit SARS-CoV-2 in-vitro. CQ has shown to alter the pathogenesis of the disease in-vitro by increasing endosomal pH and altering the glycosylation of ACE2 receptors. CQ has significant immunomodulatory activity and also increases the activity of regulatory T-cells. In a recent randomized controlled trial, CQ was found to be more effective than lopinavir-ritonavir. But, CQ is a well-known antimalarial drug, and its overuse may become a reason for its resistance. Also, the toxicity of CQ is another major challenge. Hydroxychloroquine (HCQ), a derivative of CQ, is less toxic. However, there have been contradictory reports regarding its potency. A research group found it to be more potent than CQ, while the other group found it to be less potent. In the study conducted by Yao et al., 0.72µM was found to be the EC50 required to inhibit the SARS-CoV infected Vero cells. PBPK model established that HCQ 400 mg BD was the loading dose needed to achieve the concentration mentioned above on the first day, accompanied by 200mg two times a day for SARS-CoV-2 infection.

Rationale behind research:

Numerous clinical trials comparing the efficacy of HCQ with other therapies for COVID-19 have been initiated worldwide. However, the results of only 7 studies have been reported and that is why researchers conducted this analysis.

Objective:

The objective of this first systematic and meta-analysis study was to estimate the safety and efficacy of HCQ for COVID-19 patients.

Literature Search:

A total of 16 literature databases (CINAHL, Wiley online library, SCOPUS, Web of Science, Embase, medRxiv and bioRxiv, Pubmed, OVID, Cochrane CENTRAL, Epistemonikos, PAHO (Pan American Health Organization), Trip Database, Science Direct, Nature,  CNKI and mediterranee-infection.com/pre-prints-ihu, Virtual Health Library (VHL)) were searched from the date of origin till April 8th 2020. To find out the articles of high relevance, the reference list of the identified articles was thoroughly screened. No language barrier was there. The main keywords used for the search were 2019 novel coronavirus, coronavirus disease 2019, 2019-nCoV, COVID-19, Hydroxychloroquine, Hydroxychloroquine sulfate, Chloroquine and Plaquenil.

Inclusion criteria:

Setting: The systematic review part of the study included single group prospective observational/ interventional studies, case studies, RCTs and other observational study designs. Whereas, for the meta-analysis part, only RCTs and retrospective and prospective observational comparative studies were considered.

Participants: The patients diagnosed with COVID-19 confirmed by the lab were included

Study Drug: Hydroxychloroquine

Control: Conventional/Standard therapy

Objectives/Outcomes:

• Clinical cure (Time to cough relief, Time for body temperature to get normal)
• Virological cure after 6 or 7 days of the beginning of therapy
• Death or worsening of disease during treatment
• Radiological progression during treatment
• Infection recurrence during the treatment
• HCQ's safety and tolerability

Comparisons:

• HCQ versus standard conventional therapy/control
• HCQ combination therapy vs. conventional therapy/control

Study selection:

After completing the database search and removal of duplicate articles, the independent screening of abstracts or titles was initiated using the criteria for selection by two authors (HRDK and HK). The full text for further evaluation was collected for all the articles where were relevant.

Risk of Bias:

The Cochrane risk of bias tool for randomized controlled studies was used for RCTs. ROBINS-I tool was used for the non-randomized interventional studies. Newcastle Ottawa Scale was used for the observational studies. The Possibility of bias was separately estimated by the three authors using the above tools. A funnel plot was not utilized for calculating publication bias as for meta-analysis part, only three studies were included.

Data Extraction:

Two authors separately carried out the data extraction using the pre-tested data extraction forms. These forms were in accordance with the template given by Cochrane data extraction. Google translate was used for the articles which were published in a language other than English.

Assessment of heterogeneity:

Chi-square test and I2 statistics were used to estimate the statistical heterogeneity. An I2 value of 0<40% is not regarded as statistically significant. Moderate heterogeneity is the I2 value of 30-60%, 50-90% is substantial heterogeneity, and 75-100% is the significant one.

Statistical Analysis:

As all the data were dichotomous, the point estimate was measured using either risk ratio (RR) or odds ratio (OR) in addition to 95% CI. As considerable clinical heterogeneity was lacking, the meta-analysis was performed using the inverse-variance method or Mantel Hazel method for continuous and dichotomous data, respectively. In case of low to moderate statistical heterogeneity, the data were pooled using the fixed-effect model; otherwise, the random-effects model was employed.  

Outcomes:

Comparison 1: HCQ versus standard conventional therapy/control

Three studies compared the efficacy and safety of HCQ with the standard conventional therapy or control (n=128).

1. Clinical cure:

• Duration of cough: A study conducted by Zhaowei et al., 2020, showed a significant decrease in the number of cough days with HCQ (2.0 ± 0.2 days) as compared to the control group (3.1 ± 1.5 days).
• Time to body temperature normalization: The mean/median time for the temperature to get normal was reported by two studies (normalization maintained for at least 72 hours). A study conducted by Jun et al., 2020 found that in the HCQ group, the time for body temperature normalization was 1 (0-3) days whereas it was 1 (0-2) days in the control group. Another study by Zhaowei et al., 2020 found significantly lesser time for body temperature normalization with HCQ (2.2 ± 0.4 days) compared to 3.2 ± 1.3 days for the control group.

2. Virological cure after 6 or 7 days of the beginning of therapy: Two studies compared the virological score on day 6-7. There was no difference in the virological score between the two groups (HCQ and control). Random effect model was used due to high heterogeneity.

3. Death or worsening of disease during treatment: The death or clinical worsening of the disease was reported by all the three studies (HCQ arm (n=66), Control group (n=62). A total of 20 patients received HCQ alone (lost to follow-up=6) in a study conducted by Gautret et al., 2020.  For analysis, the last observation carried forward (LOCF) was utilized. Worsening of clinical condition was considered if the patient needed ICU during the therapy. There was no difference between the two arms OR 1.37 (95% C.I. 0.09 to 21.97) in terms of death or clinical worsening of the disease. Random effect model was used due to moderate heterogeneity (I2=59%).

4. Radiological progression during the treatment: The radiological progression of lung damage/pneumonia, as shown by CT scan was significantly decreased with the HCQ therapy (OR 0.31 (0.11 to 0.9)). Fixed effect model was used due to low heterogeneity.

5. Recurrence of infection during the treatment: This was defined as the negativity of PCR results initially during the treatment followed by recurrence of positivity of PCR results. A study by Gautret et al, 2020, showed that a patient who received HCQ and azithromycin tested negative after 6 days of starting therapy and again tested positive on day 8.

6. Safety of HCQ:  In the HCQ group (n=66), seven adverse events were reported while only three adverse events were reported in the standard treatment group (n=62). A study by Jun et al., 2020 reported abnormal liver function and diarrhoea in four patients (26.7%) of HCQ group and three patients (20%) of the control group. A study conducted by Zhaowei et al., 2020, reported mild adverse reactions in two patients, rash in one patient and headache in one patient with the HCQ therapy. Gautret et al. 2020 in their study reported termination of treatment in one patient due to nausea on day three and one patient death with HCQ therapy (Death case was not included as an adverse effect as the details of the case were not available). The combined results suggested no considerable difference in the occurrence of adverse effects between the two arms [OR 2.19 (0.59 to 8.18)]. Fixed effect model was used due to low heterogeneity (I2=0).

Sensitivity analysis: Due to the high risk of bias of the first study on HCQ by Gautret et al, 2020, a sensitivity analysis was conducted. The same set of data was analyzed and the study data of Gautret et al, 2020 was removed from the analysis. Even after removing data, there was no difference in terms of the clinical cure, virological cure and safety of HCQ.

Comparison 2: HCQ combination therapy vs. conventional therapy/control.

Efficacy: 

• The efficacy of HCQ + azithromycin was estimated in four studies, while the safety of the combination was evaluated in the five studies. Two studies among these were conducted by Gautret et al., 2020 and the patient population in the first study was also included in the second study. In the  Gautret et al., 2020 first study, the combination of HCQ and azithromycin (n=6) caused 100% virological cure as compared to 57.1% with the HCQ monotherapy (n=14) and 12.5% (n=16) with the control treatment. The safety data was not available.
• The second single-arm study by the same researchers with a greater sample size (n=80 COVID-19 cases) reported virological cure in 83% patients on day seven and in 93% of patients on day 8. While the study report was published, the discharge was noted in 65 patients with a mean length of hospital stay of 4.6 days. The same group in their other study reported virological cure in 91.7% patients on day 10. A total of 4.3% of patients had a poor outcome with the mortality rate of 0.47%.
• A single group prospective study estimated the efficacy of the combination of HCQ and azithromycin. No significant efficacy of the combination at the same dose was established as 8 of the 10 patients tested positive for the virus post 5-6 days of therapy. One patient died, and two required ICU of the total of 11 patients included in the study. However, 8 out of the 11 included patients were of COVID-19 with other serious co-morbidities.

Safety:

• A second study conducted by Gautret et al., 2020 found the commonly reported adverse events with the combination therapy; diarrhoea (5%), nausea/vomiting (2.5%) and blurring of vision (1.2%). No patient reported any signs of cardiac toxicity in the study by Million et al., 2020. A study by Molina et al. reported persistent QT prolongation in one patient due to which medicines had to be withdrawn. In a survey by Chorin et al., 2020, 84 patients were recruited. 30% of patients had QTc prolongation by >40 ms while 11% showed QTc of more than 500 ms. As per the multivariate analysis, the development of acute renal failure was found to be the powerful predictor of extreme QTc prolongation.

The present study reported the overall safety and efficacy of HCQ by reducing the number of patients showing the radiological progression with a similar rate of adverse effects shown by control/standard/conventional treatment.

The treatment with HCQ effectively reduces the number of cough days and time for the body temperature to normalize. But, no significant effect was reported in terms of composite death or worsening of the disease and virological cure post 6-7 days of beginning the therapy. HCQ, as well as the control group, were not found to be different in terms of safety.

A study by Gautret et al., 2020 reported recurrence of the disease in one patient while the patient was still receiving HCQ plus azithromycin combination treatment. This could be possibly due to the drug resistance during the treatment and requires thorough monitoring.

The results depicting the efficacy of HCQ + Azithromycin combination treatment are inconclusive and are reported mainly by the same research group. The mild adverse events like nausea/vomiting, blurred vision and diarrhoea have been reported in the study conducted by Gautret et al., 2020. One patient reported electrocardiographic evidence of QT prolongation in a survey by Molina et al., 2020. A study by Chorin et al., 2020 reported significant QTc prolongation (>500 ms) in 11% of patients on combination treatment. Also, the study reported the development of acute renal failure as a critical predictor of extreme QTc prolongation. More clinical studies are needed to draw a definite conclusion regarding the efficacy and safety of HCQ + Azithromycin combination.