Most but not all observational studies of statin treatment of COVID-19 patients suggest that treatment improves outcomes. However, almost all observational studies fail to consider what cardiovascular investigators have known for 15-20 years: withdrawing statins after hospital admission has detrimental effects on patient outcomes. Continuing (or starting) statin treatment after hospital admission consistently improves COVID-19 patient outcomes, whereas discontinuing treatment does not. Thus, observational studies of the effectiveness of statin treatment of COVID-19 patients must consider the consequences of statin withdrawal.