Investigators with the Office of Inspector General are recommending a closer look at federal regulators’ controversial “two-midnight” rule for Medicare beneficiaries.

An OIG report released in late December found “vulnerabilities” caused by the policy, which requires hospital stays spanning at least “two midnights” to qualify for skilled nursing care.

Report authors recommend that the Centers for Medicare & Medicaid Services improve oversight of the policy and “analyze the potential impacts of counting time spent as an outpatient toward the 3-night requirement for SNF services so that beneficiaries receiving similar hospital care have similar access to these services.”

The report found that an increasing number of Medicare beneficiaries in outpatient stays had more limited access to skilled nursing services than they would have, had they been qualified as an inpatient stay. Investigators analyzed Medicare hospital claims from fiscal years 2013 and 2014 to assess the policy, which was implemented in fiscal 2014.

That year Medicare beneficiaries had 633,000 hospital stays that lasted at least three nights but did not include three inpatient nights, a necessity to becoming eligible for Medicare SNF coverage. That number represents a 6% increase of non-SNF eligible stays over fiscal 2013, the OIG noted.