In this post, we analyze the 1622 COVID related articles published up to the 14th of July, with the term Meta-analysis in the title, available in Scopus. We conducted a keyword co-occurrence analysis, and a coupling analysis.
With the vast amounts of research on COVID, and the value in examining the results of multiple studies, meta-analysis are important studies, that generally yield more reliable results, as well as potentially identifying moderators and mechanisms single studies are ill-suited for.
In the keyword co-occurrence analysis, we se the terms group into 9 clusters. We include the top 10 keywords in each cluster in the table below.
Cluster 1 | Cluster 2 | Cluster 3 | Cluster 4 | Cluster 5 | ||||||||||||||
Keyword | Weighted degree | Occurrence | Keyword | Weighted degree | Occurrence | Keyword | Weighted degree | Occurrence | Keyword | Weighted degree | Occurrence | Keyword | Weighted degree | Occurrence | ||||
artificial ventilation | 150 | 3123 | viral pneumonia | 415 | 6741 | mortality | 509 | 7898 | disease severity | 346 | 6797 | virology | 268 | 4516 | ||||
mortality rate | 140 | 2882 | prevalence | 307 | 4870 | risk factor | 299 | 5245 | prognosis | 167 | 3353 | procedures | 139 | 2039 | ||||
treatment outcome | 173 | 2709 | clinical outcome | 138 | 2572 | comorbidity | 226 | 4329 | severity of illness index | 156 | 2963 | quality control | 104 | 1914 | ||||
antivirus agent | 90 | 2084 | risk assessment | 130 | 2211 | hypertension | 168 | 3556 | c reactive protein | 92 | 2701 | isolation and purification | 102 | 1735 | ||||
adult respiratory distress syndrome | 86 | 2048 | epidemiology | 131 | 1771 | diabetes mellitus | 162 | 3353 | blood | 123 | 2533 | nonhuman | 75 | 1541 | ||||
hydroxychloroquine | 82 | 1855 | age | 89 | 1715 | disease association | 163 | 3100 | d-dimer | 76 | 2029 | diagnosis | 90 | 1472 | ||||
drug efficacy | 83 | 1715 | sars | 88 | 1442 | outcome assessment | 133 | 2450 | procalcitonin | 50 | 1556 | children | 82 | 1442 | ||||
drug therapy | 102 | 1500 | cohort analysis | 62 | 1252 | cardiovascular diseases | 111 | 2306 | biological marker | 67 | 1511 | pathogenicity | 64 | 1401 | ||||
antiviral agents | 73 | 1459 | infection risk | 70 | 1243 | mortality risk | 77 | 1429 | laboratory test | 51 | 1459 | reverse transcription polymerase chain reaction | 58 | 1100 | ||||
lopinavir plus ritonavir | 46 | 1447 | medline | 60 | 1190 | retrospective study | 72 | 1371 | lactate dehydrogenase | 48 | 1449 | real time polymerase chain reaction | 51 | 996 | ||||
drug safety | 68 | 1429 | major clinical study | 55 | 1074 | newcastle-ottawa scale | 74 | 1337 | interleukin 6 | 56 | 1414 | immunology | 47 | 968 | ||||
drug effect | 71 | 1299 | sex difference | 52 | 1029 | chronic obstructive lung disease | 52 | 1315 | metabolism | 63 | 1360 | genetics | 43 | 850 | ||||
corticosteroids | 50 | 1241 | adolescent | 53 | 981 | disease course | 57 | 1178 | disease exacerbation | 61 | 1336 | clinical laboratory techniques | 36 | 816 | ||||
azithromycin | 46 | 1222 | health care personnel | 59 | 858 | malignant neoplasm | 45 | 1176 | biomarkers | 57 | 1253 | laboratory technique | 36 | 816 | ||||
chloroquine | 47 | 1080 | practice guideline | 43 | 836 | very elderly | 55 | 1106 | lymphocyte count | 45 | 1212 | diagnostic accuracy | 29 | 527 | ||||
Cluster 6 | Cluster 7 | Cluster 8 | Cluster 9 | |||||||||||||||
Keyword | Weighted degree | Occurrence | Keyword | Weighted degree | Occurrence | Keyword | Weighted degree | Occurrence | Keyword | Weighted degree | Occurrence | |||||||
intensive care units | 219 | 4354 | fever | 124 | 3250 | diarrhea | 87 | 2179 | pathophysiology | 115 | 2198 | |||||||
complication | 233 | 3744 | clinical features | 121 | 2951 | aspartate aminotransferase | 62 | 1759 | headache | 50 | 1319 | |||||||
hospitalization | 178 | 3609 | coughing | 105 | 2724 | alanine aminotransferase | 58 | 1677 | cerebrovascular disease | 45 | 1087 | |||||||
hospital admission | 121 | 2476 | dyspnea | 83 | 2409 | vomiting | 48 | 1314 | cerebrovascular accident | 30 | 682 | |||||||
incidence | 130 | 2316 | fatigue | 67 | 1915 | nausea | 45 | 1231 | hospital discharge | 33 | 636 | |||||||
hospital mortality | 69 | 1331 | ct | 83 | 1666 | abdominal pain | 42 | 1056 | dizziness | 18 | 555 | |||||||
hospital patient | 64 | 1277 | myalgia | 53 | 1496 | bilirubin | 31 | 1004 | anosmia | 28 | 426 | |||||||
acute kidney failure | 52 | 1167 | lymphocytopenia | 46 | 1399 | gastrointestinal symptom | 39 | 924 | nausea and vomiting | 15 | 407 | |||||||
intensive care | 49 | 1001 | pathology | 75 | 1333 | thrombocytopenia | 37 | 850 | neurologic disease | 20 | 334 | |||||||
heart injury | 39 | 947 | pneumonia | 57 | 1240 | liver disease | 36 | 808 | smelling disorder | 23 | 311 | |||||||
critical illness | 44 | 779 | sore throat | 35 | 1168 | anorexia | 22 | 698 | brain ischemia | 13 | 273 | |||||||
invasive ventilation | 31 | 690 | diagnostic imaging | 50 | 993 | liver injury | 31 | 650 | brain hemorrhage | 12 | 261 | |||||||
acute kidney injury | 38 | 609 | infant | 40 | 953 | aspartate aminotransferase blood level | 17 | 561 | ageusia | 12 | 252 | |||||||
lung embolism | 30 | 595 | pregnancy | 46 | 846 | alanine aminotransferase blood level | 15 | 503 | olfaction disorders | 17 | 219 | |||||||
heart arrhythmia | 26 | 577 | symptoms | 37 | 786 | gastrointestinal disease | 27 | 486 | taste disorder | 13 | 216 |
The coupling analysis gives a similar clustering. If you open the map in VOSviewer, it is possible to click on individual studies, see which the are closely linked to, and open the paper directly in a browser.
VOSViewer files:
To open the map directly in VOSviewer, please use the coupling MAP and NET files from December 1st, available through the Open Science Foundation (OSF) repository:
https://osf.io/54gqw/