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:

Our hypothesis was that high hemoglobin (Hb) level might be associated with hypercoagulable state and death due to COVID-19. Of the 9467 hospitalized COVID-19 patients, patients were subdivided into 5 groups based on the level of Hb; Hb < 10 g/dL, 10 g/dL </= Hb < 12 g/dL, 12 g/dL </= Hb < 14 g/dL, 14 g/dL </= Hb < 16 g/dL, and Hb >/= 16 g/dL. Compared to patients with 12 g/dL </= Hb < 14 g/dL, patients with Hb >/= 16 g/dL had significantly higher adjusted in-hospital mortality (OR [95% CI] 1.62 [1.15-2.27], P = 0.005).
["Diagnosis", "Treatment"]