Visual analysis of the research trend and status on the association between vitamin D and immunity: From 2012 to 2021

Objective We conducted this study to visualize hot spots and trends in the correlation between vitamin D and immunity over the past decade with bibliometric analysis. Methods We collected relevant articles in the Web of Science Core Collection from 2012 to 2021 as the data source, and then used CiteSpace software to perform the data analysis. Some graphics were done with Graphpad software. Results A total of 1,656 articles were retrieved, with an average citation count of 25.2 times. The United States (439 articles, 26.51%) has the top number of published articles, followed by China (164 articles, 9.90%), England (135 articles, 8.15%), Italy (114 articles, 6.88%), and India (82 articles, 4.95%). The most literature is found in areas of Immunology (337 articles, 20.35%) and Biochemistry Molecular Biology (179 articles, 10.81%). In terms of institutions, the top five institutions with the highest number of publications all belong to Europe. Among them, the League of European Research Universities (LERU) (121, 7.31%) has a greater proportion of output articles. The United States Department of Health Human Services (225, 13.59%) and National Institutes of Health United States (223, 13.47%) funded most articles. The leading five authors with the largest number of publications were Hewison M (19, 1.15%), Bergman P (14, 0.85%), Agerberth B (13, 0.76%), Carlberg C (12, 0.73%), and White JH (12, 0.73%). The top five keywords with the highest co-occurrence frequency are “vitamin d” (367), “d deficiency” (217), “expression” (195), “association” (151), and “d receptor” (132). Among the 17 keyword clusters, the largest cluster is #0 “diet.” Despite cluster #13 “covid-19,” most of the clusters were conducted the studies before 2012. Conclusion The overall development of research in this field is promising. Western developed countries made outstanding contributions in this area and still take the leading role. But the participation of developing and low-income countries is also impressive. The potential therapeutic effects of vitamin D in immune-related diseases have been noted, especially in multiple sclerosis, COVID-19, etc. This is also the focus and frontier of current research. However, there is still no consensus conclusion in this field. Further research is needed in the future.

Bibliometric analysis of the global research status and trends of the association between Vitamin D and infections from 2001 to 2021

Objective The objective of this study was the visualization of hot spots and evolving trends in research on the association between vitamin D and infections through the use of bibliometric analysis. Methods Based on 3046 relevant articles collected in the Web of Science Core Collection for the period of 2001–2021, the data were processed using CiteSpace software. GraphPad software was used for some of the graphics. Results A total of 3,046 literature were retrieved, with an average citation frequency of 27.89 times. The number of published papers in the direction of “Immunology” (453 articles, 14.9%) and “Infectious diseases” (312 articles, 10.2%) is much higher. The United States presents the highest publication count (890, 29.2%) and shows a strong leadership in this field. Country burst shows that since 2015, many developing countries and low-income countries have carried out enthusiastic research in this regard, including China, Pakistan, and Iran. As for institutions, the League of European Research Universities produces a larger proportion of articles (220, 7.2%). In terms of authors, Martineau AR and Camargo CA have the highest number of published articles, contributing 30 (0.99%) and 28 articles (0.92%), respectively. Major studies are supported by the United States Department of Health Human Services funding (394, 12.9%). According to the keyword co-occurrence diagram, the 10 most frequent keywords from 2001 to 2021 are “vitamin D”, “infection”, “d deficiency”, “risk”, “association”, “expression”, “disease”, “d supplementation”, “vitamin d deficiency”, and “children”. The top 10 cited articles in 2021 are all related to COVID-19, suggesting it is a hotspot in recent times. Conclusion Research on the association between vitamin D and infection has grown rapidly since 2012 and is generally developing well. While developed Western countries continue to be leading roles in this field, research trends in developing countries are also very promising. It is demonstrated that the relationship between vitamin D and respiratory infections, especially respiratory viruses and the more recently COVID-19, has received a lot of attention in the last two decades, suggesting that this is the hotspot and frontier of research issue.

Impact of apixaban treatment discontinuation on the risk of hospitalization among patients with nonvalvular atrial fibrillation and COVID-19.

INTRODUCTION: This study evaluated the risk of hospitalization among nonvalvular atrial fibrillation (NVAF) patients with an outpatient COVID-19 diagnosis who discontinued vs continued apixaban treatment. METHODS: Adult patients with NVAF with an apixaban prescription prior to an outpatient COVID-19 diagnosis were identified from Optum Clinformatics claims database (1 April 2020-31 March 2021). Continuers were those who continued apixaban as of the index date (date of initial outpatient COVID-19 diagnosis) and discontinuers were those who had the last day of apixaban supply on or before index. Patients were followed from COVID-19 diagnosis to change of continuation/discontinuation status, switch, death, end of continuous coverage or study end, whichever occurred first. Inverse probability treatment weighting (IPTW) was performed to balance cohorts. Cox proportional hazard models were used to compare the risk of all-cause hospitalization and hospitalization for ischemic stroke (IS), venous thromboembolism (VTE), myocardial infarction (MI), bleeding and mortality. RESULTS: A total of 7869 apixaban patients with COVID-19 were included: 6676 continuers (84.8%) and 1193 discontinuers (15.2%). Compared with continuers, discontinuers had a higher risk of all-cause hospitalization (hazard ratio [HR]: 1.23; 95% confidence interval [CI]: 1.08-1.40), IS (HR: 2.00; 95% CI: 1.03-3.87), VTE (HR: 2.37; 95% CI: 1.06-5.27) and mortality (HR: 2.28; 95% CI: 1.85-2.80). There were no significant differences in the risk of MI (HR: 1.01; 95% CI: 0.54-1.90) or bleeding-related hospitalization (HR: 1.13; 95% CI: 0.73-1.76). CONCLUSION: NVAF patients with COVID-19 who discontinued apixaban had a higher risk of hospitalization and thrombotic events vs those who continued apixaban, with no significant difference in bleeding-related hospitalization.

Thrombotic and bleeding events, mortality, and anticoagulant use among 546,656 hospitalized patients with COVID-19 in the United States: a retrospective cohort study.

This study describes demographics, thrombotic and bleeding events, mortality, and anticoagulant use among hospitalized patients with COVID-19 in the United States. Premier Healthcare Database data were analyzed to identify inpatients with a discharge diagnosis for COVID-19 (ICD-10-CM code: U07.1) from April 1, 2020 to March 31, 2021, and matched historical controls without COVID-19 (inpatients discharged between April 1, 2018 and March 31, 2019). Thrombotic [including venous thromboembolism (VTE)] and bleeding events were based on ICD-10-CM discharge diagnosis codes. Of the 546,656 patients hospitalized with COVID-19, 20.1% were admitted to the ICU, 62.8% were aged ≥ 60 years, 51.5% were male, and 31.0% were non-white. Any thrombotic event was diagnosed in 10.0% of hospitalized and 20.8% of ICU patients with COVID-19 versus (vs) 11.5% and 24.4% for historical controls, respectively. More VTE events were observed in hospitalized and ICU patients with COVID-19 than historical controls (hospitalized: 4.4% vs 2.7%, respectively; ICU: 8.3% vs 5.2%, respectively; both P < 0.0001). Bleeding events were diagnosed in 10.2% of hospitalized and 21.8% of ICU patients with COVID-19 vs 16.0% and 33.2% for historical controls, respectively. Mortality among hospitalized (12.4%) and ICU (38.5%) patients with COVID-19 was higher vs historical controls (2.4%, P < 0.0001 and 9.4%, P < 0.0001, respectively) and higher in hospitalized patients with COVID-19 who had thrombotic events (29.4%) vs those without thrombotic events (10.8%, P < 0.0001). VTE and mortality were higher in hospitalized and ICU patients with COVID-19 vs historical controls. The presence of thrombotic events was associated with worse outcomes.