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:

PURPOSE: The aim of this study was to evaluate risk factors for COVID-19 infection and mortality and to document if any relation exists between 25 (OH) Vitamin D and COVID-19 infection. METHODS: This retrospective study evaluated 151 HD patients. Patients infected with COVID-19 were compared to patients without the infection. Risk factors for intensive care unit (ICU) stay and mortality were analyzed. Deceased infected patients were also compared to patients who died due to other causes. RESULTS: The mean age of all HD patients was 57.15 +/- 15.73 years and 51.7% were male. The mean 25 (OH) Vitamin D level of all patients was 16.48 +/- 8.45 ng/ml. Thirty-five infected patients were significantly older, had a higher Charlson comorbidity index (CCI) score. They also had a higher number of patients with diabetic nephropathy, cerebrovascular accident (CVA) and coronary heart disease (CHD). Patients who needed to stay in ICU had higher CCI score, a higher number of patients with diabetic nephropathy, pulmonary diseases and had statistically significantly higher CRP levels. Deceased infected patients were significantly older, had higher CCI scores and lower PTH than survived infected patients. Deceased infected patients had lower PTH, but had significantly lower leukocyte, lymphocyte counts and urea levels at admission when compared to patients who died due to other causes. Patients with poor prognosis had lower neutrophil and lymphocyte counts before infection and at admission; respectively. 25 (OH) Vitamin D level was not related to the risk of COVID-19 infection, ICU stay or mortality. CONCLUSION: Older age, higher CCI scores, diabetic nephropathy, CHD, CVA, pulmonary diseases, and lower neutrophil and lymphocyte counts were found as poor prognostic factors. The comparisons yielded no significant finding for 25 (OH) Vitamin D, acetylsalicylic acid, erythropoietin, intravenous iron, ACEI, ARBs, and dialysis adequacy parameters.
["Diagnosis", "Treatment"]