You are presented with a paragraph from a COVID-19 literature. Classify the topics of this piece of text by choosing from the following categories:

- Epidemic Forecasting: The content relates to predictions about the spread of COVID-19.
- Treatment: The paragraph discusses therapeutic methods or medication for COVID-19.
- Prevention: The content covers measures to prevent the spread of COVID-19.
- Mechanism: The paragraph explains the biological mechanisms of the virus.
- Case Report: The content is a report of a COVID-19 case.
- Transmission: The paragraph discusses how COVID-19 is transmitted.
- Diagnosis: The content is about diagnosing COVID-19 in individuals.

Your classification should be provided as an element within a JSON array. The array should be formatted with topics enclosed in double quotes and separated by commas, following the JSON format, for example: ["Topic1", "Topic2", ...]. Include all applicable topics within the array. Your output should be a valid JSON array, and no additional text should be included in your response.

Article:

OBJECTIVE: To determine the difference in the rate of thromboembolic complications between hospitalized coronavirus disease 2019 (COVID-19)-positive compared with COVID-19-negative patients. PATIENTS AND METHODS: Adult patients hospitalized from January 1, 2020, through May 8, 2020, who had COVID-19 testing by polymerase chain reaction assay were identified through electronic health records across multiple hospitals in the Mayo Clinic enterprise. Thrombotic outcomes (venous and arterial) were identified from the hospital problem list. RESULTS: We identified 3790 hospitalized patients with COVID-19 testing across 19 hospitals, 102 of whom had positive test results. The median age was lower in the COVID-positive patients (62 vs 67 years; P=.03). The median duration of hospitalization was longer in COVID-positive patients (8.5 vs 4 days; P<.001) and more required intensive care unit care (56.9% [58 of 102] vs 26.8% [987 of 3688]; P<.001). Comorbidities, including atrial fibrillation/flutter, heart failure, chronic kidney disease, and malignancy, were observed less frequently with COVID-positive admissions. Any venous thromboembolism was identified in 2.9% of COVID-positive patients (3 of 102) and 4.6% of COVID-negative patients (168 of 3688). The frequency of venous and arterial events was not different between the groups. The unadjusted odds ratio (OR) for COVID-positive-patients for any venous thromboembolism was 0.63 (95% CI, 0.19 to 2.02). A multivariable logistic regression model evaluated death within 30 days of hospital discharge; neither COVID positivity (adjusted OR, 1.12; 95% CI, 0.54 to 2.34) nor thromboembolism (adjusted OR, 0.90; 95% CI, 0.60 to 1.32) was associated with death. CONCLUSION: Early experience in patients with COVID-19 across multiple academic and regional hospitals representing different US regions demonstrates a lower than previously reported incidence of thrombotic events. This incidence was not higher than a contemporary COVID-negative hospitalized comparator.
["Diagnosis"]