An Analysis on the Clinical Features of MHD Patients with Coronavirus Disease 2019: A Single Center Study

Background: In this study, we aimed to find out the features of the maintenance hemodialysis (MHD) patients infected with Coronavirus Disease 2019 (COVID-19) in and provide evidences for clinical treatment. Methods: We collected the data of all the MHD patients in this hemodialysis center by February 20, 2020, including those infected with COVID-19. These patients were divided into three groups: the control group (537 cases), confirmed group (66 cases) and suspected group (24 cases). We compared the relevant data of the three groups and analyzed the factors that may affect the possibility of catching COVID-19. Results: 1. By February 20, 2020, there were 627 MHD patients in the Hemodialysis Center of Wuhan No.1 Hospital. The prevalence rate of the COVID-19 was 14.35% (90/627, including 66 confirmed cases and 24 suspected cases); the fatality rate 13.33% (12/90, including 12 death cases); the mortality rate 1.91% (12/627). 2. The comparison between the three groups revealed the following results: weekly hemodialysis duration (WHD), ultrafiltration volume (UFV) and ultrafiltration rate (UFR) of the confirmed group were obviously lower than those of the control and suspected groups ( P 0.05); the neutrophil ratio (N%), neutrophil (N#), monocyte (M#) and total carbon dioxide (TCO 2 ) were significantly higher than those of the control group while the lymphocyte ratio (L%) was much lower ( P 0.05). 3. The lung CT scans found three common features: bilateral abnormalities (81.54%), multiple abnormalities (84.62%) and patchy opacity (61.54%). 4. The binary logstic regression analysis showed that diabetes ( OR =5.404,95% CI 1.95014.976, P =0.001) and hypertension ( OR =3.099,95% CI 1.3806.963, P =0.006) are independent risk factors

cases and 24 suspected cases); the fatality rate 13.33% (12/90, including 12 death cases); the mortality rate 1.91% (12/627).2. The comparison between the three groups revealed the following results: weekly hemodialysis duration (WHD), ultrafiltration volume (UFV) and ultrafiltration rate (UFR) of the confirmed group were obviously lower than those of the control and suspected groups (P 0.05); the neutrophil ratio (N%), neutrophil (N#), monocyte (M#) and total carbon dioxide (TCO 2 ) were significantly higher than those of the control group while the lymphocyte ratio (L%) was much lower (P 0.05).3. The lung CT scans found three common features: bilateral abnormalities (81.54%), multiple abnormalities (84.62%) and patchy opacity (61.54%). 4 Conclusion: MHD patients with diabetes or hypertension are more likely to be infected with COVID-19. In clinical treatment, hemodialysis duration, UFR and SF levels should be controlled appropriately to reduce the risk of infection. 4 Background In December 2019, a series of pneumonia cases of unknown cause emerged in Wuhan, Hubei Province, China [1] . A novel coronavirus was subsequently identified as the causative pathogen, provisionally named 2019 novel coronavirus (2019-nCoV) [2,3] . This is a high-infectivity coronavirus that transmits quickly and mainly through droplet and contact. The clinical manifestations of the pneumonia include fever, fatigue, dry cough, gradually developing into dyspnea. Most of the patients have a good prognosis while some patients may develop acute respiratory distress syndrome or septic shock, or even die. New infected cases are still increasing. As we all know, hemodialysis (HD) patients tend to suffer from low immunity and complications like cardiovascular diseases and diabetes. Since HD patients need to go to hospital frequently, they are more likely to be attacked by the 2019-nCoV. Additionally, the crowded and closed space in the hemodialysis room also increase the possibility for HD patients to be infected. The research aims to describe the clinical features of MHD patients infected with COVID-19, find out the risk factors of the infection, and provide evidence for reducing the incidence of COVID-19.

Research Objects
In this single center study, all data are from the HIS system of Wuhan No.1 Hospital and all the patients have taken 2019-nCoV nucleic acid detection with their pharynx or nasal swab samples and / or had lung CT scanning.

Data Collection
General information, hemodialysis indicators and laboratory indexes of the patients were collected. A comparison between the hemodialysis indicators of the three groups showed the WHD, UFV and UFR of the confirmed group were significantly lower than those in the control and suspected group (P 0.05). (Table 2) A comparison between the laboratory indexes of the three groups revealed that the N%, N#, M#, and TCO 2 of the confirmed group were significantly higher than the control group, and that of L% much lower than the control group (P 0.05). (Table 3) The lung CT scans of 65 suspected and confirmed patients were collected. Among these patients, 12 A binary logstic regression was used to analyze the risk factors for MHD patients to be infected with NCP (confirmed cases). The binary logstic regression was applied to analyze the data collected in this research and the forward stepwise regression was adopted in multi-factor analysis.

Discussion
Existing studies indicated about half of COVID-19 patients (51%) also suffer from a number of chronic diseases [5] , among which chronic kidney disease (CKD) is one of the common diseases. CKD claims a prevalence rate of 10.8% in China's adult population and currently around 120 million CKD patients live in China [6] .This gives rise to the increasing demand of renal replacement therapy. It is estimated the incidence of HD reached 402.18 per million population in China [7] , while the pneumonia incidence of MHD patients is 14~16 times of ordinary people [8] . Therefore, MHD patients are one of the susceptible populations of COVID-19 and require high attention.
Results of this research revealed that the prevalence rate at our Hemodialysis Center was 14.35% while the case fatality rate reached 13.33%, higher than the results of single-center research by Wuhan Jinyintan Hospital [5] and significantly higher than the national total CFR (2.3%) [9] . MHD patients tend to suffer from multiple basic diseases, including hypertension, diabetes and coronary heart disease, and are susceptible to anemia, hypoalbuminemia, hyperphosphatemia and other factors that may increase death risk. The attack of the 2019-nCoV on their already weak immune system could be fatal. In this study, the primary diseases of COVID-19 patients included primary glomerulonephritis (37.78%), hypertension (26.67%) and diabetes (17.78%), a combination slightly different from other studies that surveyed patient groups with primary diseases of diabetes (20%), hypertension (15%) and cardiovascular diseases (15%) [1] . Logstic regression analysis revealed that hypertension and diabetes are among the independent risk factors of COVID-19. Therefore, more importance should be attached to controlling the primary diseases like hypertension and diabetes on MHD patients. COVID-19 patients in this research have an average age of 61.34 years old, older than that of similar studies (55.5 years old) [5] , which might accounted for the higher mortality rate in this study. In addition, the most common clinical manifestations for COVID-19 patients in this study are cough (36%), followed by fatigue(16%) and dyspnea (16%), which is slightly different from other studies that reported fever as the main symptom [1,5] . Besides, this study found the majority of MHD patients (26%) displayed no clinical manifestations, similar to the results of certain studies [10] . This would significantly increase the difficulty to screen COVID-19 patients. Therefore, measures should be taken in the clinical aspect to reinforce the screening of COVID-19 on MHD patients.
Meanwhile, this study revealed the WHD, UFR and UFV of the confirmed group were much lower than those of the control and suspected group. This indicates that MHD patients infected with COVID-19 might have received inadequate hemodialysis that didn't remove the excessive toxins and water from the patients, thus giving rise to a series of complications including the retention of water and sodium, electrolyte disturbance and malnutrition, increasing death risk. Moreover, though the confirmed group had a TCO 2 level falling within the normal range, its level was higher than that in the other two groups. The mechanisms behind the high TCO 2 level in the confirmed group remain unclear and require further research. The logstic regression analysis of this study revealed that the WHD, UFR and TCO 2 are the independent risk factors of COVID-19 infection. This offers the enlightenment that during the outbreak of the COVID-19, measures should be taken to lengthen hemodialysis durations for MHD patients and appropriately increase UFR, ensuring the adequacy of hemodialysis to decrease the amount of CO 2 and lower the risk of infection. The laboratory indexes revealed that the L% of the confirmed group was significantly lower than that of the control group, which is consistent with the results of similar studies [1,9,10] . The fact that the N%, N# and M# of the confirmed group were much higher than the control group indicates that MHD patients may also suffer from bacterial infection when they were infected with 2019-nCoV. Therefore, based on the patient's condition, anti-bacterium therapies might be given to MHD patients infected with COVID-19 along with anti-virus therapies.
Surveyed COVID-19 patients in his study presented in their lung CT scans common features of bilateral abnormalities, multiple abnormalities and patchy opacity. In comparison, relevant diagnostic guidelines [4,11] pointed out that COVID-19 in early stage presented the imaging features of multiple small patchy opacity or interstitial changes, followed by bilateral multiple ground-glass opacity and even pulmonary consolidation in severe cases. In this regard, screening work should be conducted in time on the lung CT scans of MHD patients to achieve early detection of the disease and put the patients in quarantine and in treatment as early as possible. Xin Fang et al [12] found that the COVID-19 might rebound and exacerbate the conditions of patients in the recovery stage. This also proves the key role lung CT scan plays in diagnosing COVID-19 in testing and locating the abnormalities and keeping dynamic observations, especially in circumstances where nucleic acid detection presents low sensitivity.
In conclusion, considering that this is a horizontal research, further longitudinal research might be required to discuss other complexities of COVID-19. Secondly, given the insufficiency and low sensitivity of 2019-nCoV nucleic acid detection reagent at the early phase of the epidemic, some MHD The normal distribution is expressed by (x±s)  The normal distribution is expressed by (x±s)The skew distribution are expressed by M (P25, P75).  Confirmed Case = 1, Non-confirmed Case = 0; Diabetes = 1, Non-diabetes = 0; Hypertension = 1, Non-hypertension = 0. Figure 1 The Distribution of Patients' Residence Places (patients/%). Note: The designations employed and the presentation of the material on this map do not imply the expression of any opinion whatsoever on the part of Research Square concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. This map has been provided by the authors.

Figure 2
Bilateral patchy ground-glass opacity Right lung multiple small patchy ground-glass opacity Figure 4 Multiple patchy ground-glass opacity right lower lobe Solitary ground-glass opacity in right lower lobe