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:

Background and Objectives: The COVID-19 pandemic is an ongoing public health emergency. Patients with chronic diseases are at greater risk for complications and poor outcomes. The objective of this study was to investigate the liver function abnormalities and clinical outcomes in patients with COVID-19 and chronic hepatitis C. Materials and Methods: This retrospective, single-center study was conducted on a cohort of 126 patients with a history of hepatitis C, confirmed with COVID-19 between 01 April 2020 and 30 December 2020. Several clinical outcomes were compared between patients with active and non-active HCV infection, and the risks of liver impairment and all-cause mortality in active HCV patients were analyzed using a multivariate logistic regression model. Results: Among 1057 patients under follow-up for chronic HCV infection, 126 (11.9%) were confirmed with COVID-19; of these, 95 (75.4%) were under treatment or achieved SVR, while in the other 31 (24.6%), we found active HCV replication. There was a significantly higher proportion of severe COVID-19 cases in the active HCV group as compared to the non-active HCV group (32.2 vs. 7.3%, p < 0.001). Multivariate analysis showed that age, sex, alanine aminotransferase, C-reactive protein, procalcitonin, and HCV viral load were significant independent risk factors for liver impairment and all-cause mortality. The length of stay in hospital and intensive care unit for COVID-19 was significantly higher in patients with active HCV infection (p-value < 0.001), and a higher proportion of these patients required mechanical ventilation. Conclusions: Active HCV infection is an independent risk factor for all-cause mortality in COVID-19 patients.
["Diagnosis", "Treatment"]