I don't have any statistics, but reporting a significant loss in ANY year will increase your DIF score which increases the likelihood that the return gets audited. That's not to say you're likely to get audited, but a higher chance than the <1% overall average. IRS computer systems are so outdated, I don't know that it takes any multi-year patterns into account, but once the return is assigned to an agent, they will look at prior year returns to see if you're been reporting losses for years. In a single year thing, if it's something like a restaurant in 2020 or a Google search shows that your business burned down that year, the agent can make a judgement call to "survey" the return and you'd never even know your return was selected for audit by the computer.
Source: former revenue agent