A population-based study would be useful to identify the association between chronic kidney disease (CKD) or acute kidney injury (AKI) and prognosis of coronavirus disease 2019 (COVID-19) patients. This retrospective study utilized the claim data from Korea. Patients who underwent COVID-19 testing and were confirmed to be positive were included and divided into the following three groups based on the presence of CKD or requirement of maintenance dialysis: Non-CKD (participants without CKD), non-dialysis CKD (ND-CKD), and dialysis-dependent CKD (DD-CKD) patients. We collected data on the development of severe clinical outcomes and death during follow-up. Severe clinical outcomes were defined as the use of inotropics, conventional oxygen therapy, high-flow nasal cannula, mechanical ventilation, or extracorporeal membrane oxygenation and the development of AKI, cardiac arrest, myocardial infarction, or acute heart failure after the diagnosis of COVID-19. AKI was defined as the initiation of renal replacement therapy after the diagnosis of COVID-19 in patients not requiring maintenance dialysis. Death was evaluated according to survival at the end of follow-up. Altogether, 7,341 patients were included. The median duration of data collection was 19 (interquartile range, 11-28) days. On multivariate analyses, odds ratio (OR) for severe clinical outcomes in the ND-CKD group was 0.88 (95% confidence interval [CI], 0.64-1.20; P = 0.422) compared to the Non-CKD group. The DD-CKD group had ORs of 7.32 (95% CI, 2.14-33.90; P = 0.004) and 8.32 (95% CI, 2.37-39.21; P = 0.002) compared to the Non-CKD and ND-CKD groups, respectively. Hazard ratio (HR) for death in the ND-CKD group was 0.79 (95% CI, 0.49-1.26; P = 0.318) compared to the Non-CKD group. The DD-CKD group had HRs of 2.96 (95% CI, 1.09-8.06; P = 0.033) and 3.77 (95% CI, 1.29-11.06; P = 0.016) compared to the Non-CKD and ND-CKD groups, respectively. DD-CKD alone was associated with severe clinical outcomes and higher mortality. There was no significant difference in frequency of severe clinical outcomes or mortality rates between the Non-CKD and ND-CKD groups. In patients not requiring maintenance dialysis, AKI was associated with old age, male sex, and high Charlson's comorbidity index score but not with the presence of CKD. HRs for patients with AKI were 11.26 (95% CI, 7.26-17.45; P < 0.001) compared to those for patients without AKI in the multivariate analysis. AKI was associated with severe clinical outcomes and patient survival, rather than underlying CKD. CKD requiring dialysis is associated with severe clinical outcomes and mortality in patients with COVID-19; however, the development of AKI is more strongly associated with severe clinical outcomes and mortality.

Immune thrombocytopenic purpura (ITP) is prevalent in children aged 2–5 years but may occur in all pediatric age groups. In 50–60% of pediatric patients, ITP is preceded by an upper respiratory tract infection 1–4 weeks before its onset. In this study, the relationship between the development of ITP and viral infections in children was assessed. We analyzed data of 6487 patients aged < 18 years with incident ITP from the Health Insurance Review and Assessment Open Access Big Data Platform (2015 to 2018) and the Korea Disease Control and Prevention Agency. The monthly positive detection rate (PDR) of seven respiratory and four acute diarrhea viruses was calculated. The virus PDR seasonal trend data was analyzed through ARIMA modeling. The ITP diagnostic data and prevalence of viral infection 1 and 2 months prior were analyzed using the Granger test. The overall male to female (M/F) ratio was 1.2, whereas it was 1.4 in the youngest age group (< 1 year). The overall ITP incidence rate was 18.1 per 100,000 person-years. Respiratory syncytial virus, rhinovirus, rotavirus, and astrovirus infections influenced ITP occurrence in children. However, rotavirus infection is positively associated with the etiology of ITP after 1–2 months.

Kawasaki disease (KD) is a systemic vasculitis that occurs mainly in children under 5 years of age and is often accompanied by coronary artery lesions. The cause of the disease remains undetermined, but it is estimated to result from viral or bacterial infections. Certain studies have shown infection as a leading cause of KD. The purpose of this study was to investigate the relationship between KD incidence and viral infections in different pediatric age groups, using the Health Insurance Review and Assessment (HIRA) Open Access Big Data Platform, to confirm seasonal trends by analyzing monthly patterns. We investigated the HIRA data of KD patients (M30.3) who were treated with intravenous immunoglobulin from 2015 to 2018. Weekly virus positive detection rate data (PDR) for this period was obtained from the Korea Disease Control and Prevention Agency for human adenovirus (HAdV), human parainfluenza virus (HPIV), human respiratory syncytial virus (HRSV), influenza virus (IFV), human coronavirus (HCoV), human rhinovirus (HRV), human bocavirus (HBoV), human metapneumovirus (HMPV), rotavirus, norovirus, and astrovirus. We then analyzed the weekly/monthly virus PDR and its association with KD incidence, including monthly incidence patterns, and seasonal trends. Seasonal trend analysis of the virus PDR was performed using the time series analysis method through ARIMA (Autoregressive Integrated Moving Average). Correlations between KD incidence and PDR at 1- and 2-month intervals were analyzed using the Granger test. A total of 16,740 patients were diagnosed with KD during the study period, mainly young children, with a male-to-female ratio of 1.35. Specifically, 15,635 (93%) patients were under 5 years of age, with an incidence rate of 172.4/100,000 person-years. Annually, the cumulative number of cases per month was the highest in January, with an average of 469 cases, and was the lowest in September, with an average of 291 cases, although most were diagnosed with KD in winter (29.3%). Granger tests showed that PDR for HRSV, rotavirus, and norovirus were related with KD incidence by 1 month, while PDR for HRSV, HRV, rotavirus, and norovirus by 2 months. This study found that detection rates of respiratory and enteric viruses preceded KD by 1–2 months. Further research is needed to confirm the association between these viruses and KD.

Background: This study aimed to evaluate the association between sex and clinical outcomes in patients with coronavirus disease (COVID-19) using a population-based dataset. Methods: In this retrospective study, insurance claims data from the Korea database were used. Patients who tested positive for COVID-19 were included in the study. All diseases were defined according to the International Classification of Diseases 10th revision. During follow-up, the clinical outcomes, except mortality, were assessed using the electrical codes from the dataset. The clinical outcomes noted were: hospitalization, the use of inotropics, high flow nasal cannula, conventional oxygen therapy, mechanical ventilation, extracorporeal membrane oxygenation, development of acute kidney injury, cardiac arrest, myocardial infarction, acute heart failure, pulmonary embolism, and disseminated intravascular coagulation after the diagnosis of COVID-19. Results: A total of 7327 patients were included; of these, 2964 patients (40.5%) were men and 4363 patients (59.5%) were women. There were no significant differences in the Charlson comorbidity index score between men and women in the same age group. The incidence of mortality and clinical outcomes was higher among men than among women. The mortality rate was the highest for the populations aged 50–64 or ≥65 years. The subgroup analyses for age, diabetes mellitus, or hypertension showed favorable results for patient survival or clinical outcomes for women compared to men. Conclusion: Our population-based study showed that female patients with COVID-19 were associated with favorable outcomes. Furthermore, the impact of sex was more evident in patients aged 50–64 or ≥65 years.

Park ES, et al. J Korean Med Sci. 2019 Nov;34(49):e316. https://doi.org/10.3346/jkms.2019.34.e316

Viral infections are a common cause of encephalitis. This study investigated the relationship between the incidence of encephalitis and that of respiratory and enteric viral infections in all age groups from 2015 to 2019, using the Health Insurance Review and Assessment (HIRA) Open Access Big Data Platform. We identified monthly incidence patterns and seasonal trends using the autoregressive integrated moving average (ARIMA). The Granger causality test was used to analyze correlations between encephalitis incidence and the positive detection rate (PDR) at 1-month intervals. A total of 42,775 patients were diagnosed with encephalitis during the study period. The incidence of encephalitis was highest in the winter (26.8%). The PDRs for respiratory syncytial virus (HRSV) and coronavirus (HCoV) were associated with the trend in encephalitis diagnosis in all age groups, with a 1-month lag period. In addition, an association with norovirus was observed in patients aged over 20 years, and with influenza virus (IFV) in patients aged over 60 years. This study found that HRSV, HCoV, IFV, and norovirus tended to precede encephalitis by 1 month. Further research is required to confirm the association between these viruses and encephalitis.