The Centers for Medicare & Medicaid Services should collaborate with states to develop a systematic approach for collecting and sharing promising practices through which states have identified and reduced improper Medicaid payments, the Government Accountability Office said in a report publicly released on Monday.

From fiscal years 2014 through 2016, according to the report, CMS conducted focused reviews of so-called program integrity efforts in 31 states. Personal care services have been determined to be a high-risk area; one review in that area was conducted in 2014 and another in 2015, the GAO said. Other Medicaid-related high-risk areas reviewed during that time included oversight of managed care plans, with 28 reviews; provider enrollment and screening, with nine reviews; and nonemergency medical transportation, with three reviews.

The focused reviews helped identify areas for improvement, state officials told the GAO. During reviews related to personal care services, CMS assessed the extent of state oversight, including processes for enrolling providers and monitoring services provided.

“CMS officials said they generally found a lack of sufficient state oversight of personal care services and non-emergency medical transportation, and recommended states take action,” the report said. “For example, in one state, CMS found that there were limited program integrity requirements in the state’s contract with the organization that conducts program integrity activities related to personal care services. The contract did not require oversight that involved unannounced visits of personal care service providers, or provide sufficient direction about the re-enrollment of those providers.”

GAO representatives spoke with officials in one state where CMS had reviewed personal care services, according to the report. “The state officials noted that … due to CMS’s review, they would pay increased attention to certain vulnerabilities,” the GAO said. “These state officials added that CMS’s focused reviews can help bring program integrity vulnerabilities to the attention of state Medicaid staff responsible for administering the program, not just their program integrity staff.”

CMS officials told the GAO that they plan to continue conducting focused reviews related to personal care services and managed care in fiscal year 2017.

CMS also should encourage states to work with agency contractors in “collaborative audits” to uncover improper Medicaid payments, the GAO recommended.