A cohort observational study was conducted to compare the clinical outcomes between older COVID-19 patients (>50 years old) who received a combination of vitamin D, magnesium, and vitamin B12 (DMB) and older patients who did not receive DMB. The primary clinical outcome was classified as needing any oxygen support or intensive care unit (ICU) support. It was found that when compared to the patients who did not receive DMB, it was significantly less likely for patients who did receive DMB to need oxygen support. Further, when adjusting for both hypertension and age, receiving DMB was a significant protective factor against exacerbation of clinical outcomes. No adverse reactions or side effects resulted from receiving DMB combination.