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:

OBJECTIVES: Low molecular weight heparin (LMWH) may provide beneficial effects on outcomes of COVID-19. We aimed to examine the impact of LMWH treatment on clinical outcomes (duration of hospitalization, admission to intensive care unit, the requirement for mechanical ventilation, and death) of COVID-19 patients with normal D-dimer levels at admission. BACKGROUND: Coronavirus disease-2019 (COVID-19) predisposes patients to arterial and venous thrombosis. METHODS: In this retrospective, multicentre and observational study we analysed the data of 308 confirmed COVID-19 patients with normal D-dimer levels at initial admission. After propensity score matching (PSM) patients were grouped; Group 1; patients who received LMWH with D-dimer </=0.5 mg/L, Group 2; patients who received LMWH after D-dimer levels exceeded 0.5 mg/L, and Group 3; patients who did not receive LMWH. RESULTS: After PSM, each group comprised 40 patients. The patients in Group1 had the best clinical outcomes compared to the other groups. Group 3 had the worst clinical outcomes (p<0.005). The benefit of LMWH increased with early prophylactic therapy especially when started while the D-dimer levels were </=0.5 mg/L. CONCLUSION: Our results strongly suggest that proactive LMWH therapy improves clinical outcomes in hospitalized COVID-19 patients even with normal D-dimer levels (</= 0.5 mg/L) (Tab. 3, Fig. 2, Ref. 34).
["Diagnosis", "Treatment"]