“H” is not for hydroxychloroquine—“H” is for heparin: lack of efficacy of hydroxychloroquine and the role of heparin in COVID-19—preliminary data of a prospective and interventional study from Brazil

More than one year ago, in December 2019, an outbreak caused a respiratory illness in Wuhan, China, caused by a novel coronavirus (nCov) and later named Coronavirus disease 2019 (COVID-19) [1]. The severe form of this disease, characterized by hypoxemic respiratory failure, was called Severe Acute Respiratory Syndrome (SARS-Cov-2) [1]. Although we have made some progress on its therapy management, the disease has unfortunately resulted in 152.406.001 confirmed cases and 3.196.275 deaths globally till now [2]^.Despite the fact that many potential vaccines were developed, there are immense logistical challenges in distributing to all vulnerable people, especially in developing countries. So, with the spread of COVID-19 moving on and a “third” wave emerging, there are no option out of caring for hospitalized patients with COVID-19.

Hydroxychloroquine (HCQ), an aminoquinolone used on the treatment of autoimmune diseases and malaria showed, on a small non-randomized trial, in the beginning of the COVID-19 pandemic, high efficacy with virologic cure when associated with azithromycin (AZTH) [3].

In Brazil, since March 2020, the Ministry of Health made available both Hydroxychloroquine and azithromycin for severe cases, at the discretion of the treating physician [4]. On May, both drugs had the recommendation expanded for mild cases [5]. With the first COVID-19 case recorded in Brazil located in São Paulo, considering the threat of the COVID-19 pandemic and with no randomized controlled trials available on timeframe, we performed an unicentric, prospective, interventional and consecutive non-randomized study to assess whether HCQ alone or in combination with azithromycin, would impact on mortality outcomes in hospitalized patients with documented pneumonia for COVID-19 on Public Health System in Brazil.

At the beginning of a frightening and unique pandemic moment, with no randomized controlled trial available, with local recommendations in favor of the use of the HCQ, our study was carried out based on ethical concerns and in order to answer the question of its benefit and guide us towards of good quality for clinical decisions. Also, the rationale and decision for prescribing this drug was based on the preliminary study in France, which showed virological cure in patients who received HCQ combined with azithromycin, the confidence and experience of Brazilians physicians with the use of HCQ for decades on the treatment of malaria, autoimmune disorders and prompt availability of the drug [2, 3].

With limitations regarding an unicentric, small number of cases and a more serious manifestation of SARS-Cov-2 infection in our cohort, our finding is consistent with a more robust data showing no benefit of HCQ in adults hospitalized with COVID-19 [5, 6]. Although in our study the cardiac toxicity effect of HCQ could not be unreliable assessed because most patients were using azithromycin and synergistic toxic effects are well known, the 5 days use of both drugs were done inpatient, so that monitoring and adherence were well controlled [7]. Also, another limitation of our study was the lack of a panel flu-test. Although part of our study occurred during influenza season and oseltamivir was administered for 76.6% of the patients, clinical symptoms can overlap with the COVID-19 [8]. Yet, RT-PCR for SARS-Cov-2 was positive in all cohort.

In our cohort, 51.3% (79/154) evolved to death during hospitalization in a median time of 21 days (95% CI, 17.047–24.953) from the onset of symptoms. In agreement with others reports, the most frequent symptoms of our patients with COVID-19 were dyspnea, cough and fever, found in 128/154 (83.1%) patients [9, 10]. Likewise, unspecific gastrointestinal symptoms of nausea, vomiting and diarrhea were seen in 17/154 (11%) patients. As expected, respiratory symptoms were present in the majority of patients.

In comparison to others studies, our casuistic comprehended more vulnerable patients with higher risk to develop complications and death by COVID-19. In our cohort, the median age of patients were 60 years and 136/154 (88.3%) of them presented comorbidities, being systemic arterial hypertension the most frequent, observed in 50.6% of them (78/154). Malignant neoplasms were present in 20.8% (32/154) of patients. Therefore, these worse clinical aspects of our casuistic may justify our higher mortality in comparison with other studies. Fei Zhou et cols. reported that in a total of 191 inpatients in a Hospital in Wuhan, China, the epicenter of the beginning of the SARS-Cov-2 pandemic, 137 were discharged and 54 (28.3%) died [11]. In this report 91 (48%) of patients presented comorbidities. In multivariate analysis, they showed, like us, that older age was associated with higher risk of in-hospital death. [11]. Wu Z et al., showed that 49% of inpatients with severe COVID-19 had comorbidities [12].

The univariate analysis showed that age equal or higher than 60 years, mechanical ventilation necessity, presence of at least two comorbidities, no heparin use and SAH were predictive of death. However, in multivariate analysis age equal or higher than 60 years and EOT necessity remained as independent factors for mortality. Interestingly, heparin use was beneficial and related to lower mortality. Age equal or higher than 60 years was also predictive for ICU admission in multivariate analysis. The ICU care was required for 76.9% (117/152) patients and 67.5% (79–117) of them evolved to death. During this study, the ICU beds were widely available and all patients were immediately admitted in this unit when necessary. In the beginning of the pandemic it was verified that risk of death increased with older age. In a Chinese series, the mortality was 0.5% in patients younger than 50 years, 2% (50–59 years), 4% (60–69 years), 8% (70–79 years) and 16% (> 80 years) [13]. The authors reported 67% of mortality in patients over 80 years, 20% between 70 and 79 years and 8% between 60 and 69 years [13]. However, the comparison of mortality among many countries is not all reliable, because of different medical resources.

Despite of the scientific advances acquired last year, till now some parts of the world are astonishing and in some words lost with this disease. In fact, in the beginning old people were dragged into this tourbillion named SARS-Cov-2 pandemic and although our cohort also found age an important and independent factor for mortality in patients with COVID-19 hospitalized, now we are faced with new mutations, younger patients requiring medical assistance and dealing with the hospitalized patient is an everyday practice for many physicians. Unfortunately, in Brazil, apart from initial recommendations regarding HCQ use, no former protocol regarding the best of care for inpatient COVID-19 was made available by the Ministry of Health until April 2021.

Aging is associated with decline of immune function, T and B lymphocytes dysfunction [14‐16] as well as lower level of interferon type 1 [17‐19]. On the other hand, old people carry more comorbidities and consequently higher probability to develop more complication in the setting of infection. Aging is also associated with a higher inflammatory steady-state caused by a higher production of cytokines [20]. These conditions certainly have contributed to the clinical severity and higher mortality associated with COVID-19 in older people [20].

Another important aspect of the COVID-19 is that an explosion of thrombi-inflammation seen in the hyper inflammation phase results in micro-thrombosis of lung vasculature and in a severe interstitial pneumonia characterized by severe hypoxemia with acute respiratory insufficiency, with necessity of high concentration of oxygen supplying and, in more severe patients, invasive ventilatory support. Less frequently, patients can also develop acute renal failure increasing the gravity of the disease [21].

Because of this physiopathology and the high rate of thromboembolic complication in patients with COVID-19 [22], prophylactic administration of low-molecular weight heparin (LMWH) for hospitalized COVID-19 patients is recommended [23]. However, Paranjpe et al. showed that systemic anticoagulation has been associated with COVID-19 benefit only in subgroup of patients with EOT [24]. Unexpectedly, at the time of this study was conducted, in the beginning of the pandemic in Brazil, we found that heparin was and independent protector factor against mortality in multivariate analysis in our casuistic. Beyond it anticoagulation action, heparin also have others functions, like inhibition of heparase enzyme and linked to endothelial leakage. It also capable of neutralizing chemokines, cytokines and the cell influx of extracellular cytotoxic histones. Moreover, heparin prevents the viral cellular uptake and interfere with leukocyte trafficking [23, 25], directly interfering with pathophysiological mechanisms associated with viral infection progression and endothelial damage.

Some limitations should be highlighted in our study. Although evaluation by computed tomography is considered the gold standard for assessing pulmonary parenchyma involvement by COVID-19 and quantifying its extension, only 76% of our patients (117/154) were evaluated using this imaging technique. Most of the remaining cases had an image evaluation done by chest radiography, because these are severe cases, including patients on mechanical ventilation, whose transport to the imaging sector offered logistical difficulties and imminent risk to the patient's life during transport. However, these cases showed evident involvement of the pulmonary parenchyma with more than 50% involvement of this organ on the chest X-ray.

Individuals with COVID-19 included in the HCQ and non-HCQ groups have comparable clinical characteristics as summarized in Table 3, with the exception of a higher percentage of neoplasia and alcoholism in the non-HCQ group. Regarding therapeutic management variables, the non-HCQ group had a lower percentage of exposure to oseltamivir, azithromycin and heparin, with a statistically significant difference. In multivariate analysis, therapy with oseltamivir and azithromycin had no impact on risk of death.

Unlike what was demonstrated by the RECOVERY study, where exposure to low doses of corticosteroids (dexamethasone) was associated with a 28-day mortality reduction in patients with COVID-19 who required mechanical ventilation [6], our study did not demonstrate a statistically significant association between treatment with corticosteroids and reduced mortality in the population included. We believe that our results may have been influenced by the lack of standardization regarding the type, dose and timing of corticosteroid introduction.

With regard to the use of heparin, only 5.2% of the patients (8/154) were not exposed to this drug, which makes the comparison groups discrepant and may lead to an analysis bias. The low prevalence of individuals in the group not exposed to heparin may affect the conclusions drawn from the results found in our study. However, the analysis of hazard ratio (HR) contemplates this difference, which makes the results found in our cohort statistically acceptable. Among the 8 patients not exposed to heparin, 5/8 did not receive the medication because they were severely thrombocytopenic and/or with active bleeding and 2/8 evolved with cardio-respiratory arrest in the first 24 h of hospital admission, making it impossible to prescribe the medication. This may have influenced the results found, since patients not treated with heparin may have had a higher mortality due to present a more severe disease. However, one point that corroborates the potential benefit of heparin in patients hospitalized with COVID-19 was the low incidence of thromboembolic events (1.29%—2/154) observed in our cohort, and possibly, this is a reflection of the massive use of prophylactic heparin in the patients included in the study. Although there was no active search for thromboembolism, several case series demonstrate higher rates of thromboembolic events in populations similar to ours [22, 26].

Despite of this work has been done to answer a question about HCQ in the setting of the COVID-19, it allowed us to take a picture of the clinical characteristics of our patients in the setting of this disease. We also could identify the main factors associated with mortality in our center.

In conclusion we confirmed that age and association of comorbid were predictive of poor prognosis in COVID-19 and higher chance of mortality. However, heparin administration was associated with less mortality and hydroxychloroquine did not influence the mortality.