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Hospitals Put on Notice: OIG to resume Short Stay Reviews

Published on 

Tuesday, December 1, 2020

The Office of Inspector General (OIG) added several new items to their Work Plan in November. Today we focus on one posted in late November, CMS Oversight of the Two-Midnight Rule for Inpatient Admissions. This type of review is not new for the OIG. In fact, targeting “short inpatient stays” has been on the OIG’s radar since before the Two-Midnight Rule.

OIG Report prior to the implementation of the Two-Midnight Rule

In July 2013, the OIG posted the completed report Hospitals' Use of Observation Stays and Short Inpatient Stays for Medicare Beneficiaries. One reason cited by the OIG for performing this review was CMS’ concern “about improper payments for short inpatient stays when the beneficiaries should have been treated as outpatients.” At that time the OIG noted that “to address these concerns, CMS recently proposed policy changes-through a Notice of Proposed Rulemaking (NPRM)-that, if promulgated as proposed, would substantially affect how hospitals bill for these stays.”

Key Findings in the OIG Report  

  • Short inpatient stays were often for the same reason as observation stays, but Medicare paid nearly three times more for a short inpatient stay than an observation stay, on average.
  • Beneficiaries also paid far more for short inpatient stays than for observation stays, on average
  • Hospitals varied widely in their use of short inpatient and observation stays.
  • Some beneficiaries had hospital stays that lasted three nights or more, but did not qualify for SNF services under Medicare.


October 1, 2013 Implementation of Two-Midnight Rule

With the implementation of the Two-Midnight Rule, in addition to scrutiny by the OIG, several Medicare Contractors have been tasked with performing short stay reviews as highlighted in the following timeline.

Timeline of Short Stay Inpatient Reviews

  • October 1, 2013: As part of the FY 2014 IPPS Final Rule the Two-Midnight Rule went into effect. Initially Medicare Administrative Contractors (MACs) were tasked with performing short stay pre-payment reviews under the then new Probe and Educate Program process.
  • October 1, 2015: The responsibility for short stay reviews shifted to the Beneficiary and Family Centered Care Quality Improvement Organizations (BFCC-QIO). Unlike the MACs, BFCC-QIO’s conducted post-payment reviews.
  • May 4, 2016: Short stay reviews were temporarily paused. At that time CMS indicated that they “took this action in an effort to promote consistent application of the medical review of patient status for short hospital stays.” In simple terms, CMS needed time to re-educate the educators.
  • September 12, 2016: BFCC-QIOS resumed short stay reviews after the following tasks were completed:
  • BFCC-QIOs completed re-training on the Two-Midnight policy;
  • BFCC-QIOs completed a re-review of claims that were previously formally denied;
  • CMS examined and validated the BFCC-QIOs peer review activities related to short stay reviews;
  • The BFCC-QIOs performed provider outreach on claims impacted by the temporary suspension; and
  • The BFCC-QIOs initiated provider outreach and education regarding the Two-Midnight policy.
  • May 8, 2019: BFCC-QIO short stay reviews were put on hold as CMS planned to procure a new BFCC-QIO contractor who would perform short stay reviews and higher-weighted-DRG reviews on a national basis. CMS anticipated awarding this contract by the 3rd quarter of calendar year 2019. To date, no contract has been awarded.


CERT Annual Supplemental Improper Payment Data

The Comprehensive Error Rate Testing (CERT) Program calculates improper payment rates for the Medicare Fee-for-Service program. Annually, the CERT publishes a report of their findings along with Medicare Fee-for-Service Supplemental Improper Payment data.

Since the Two-Midnight Rule was implemented, the annual data has included a table comparing improper payment rates for Part A hospital claims by Length of stay. While the Improper Payment Rate has dropped for “0 or 1 day” LOS claims, this group of claims continues to have the highest improper payment rate and from 2018 to 2019 seems to be going in the wrong direction.

 Percent of Improper Payments by Length of Stay
 2014 Report2015 Report2016 Report2017 Report2018 Report2019 Report
0 or 1 Day37.1%27.8%18.6%18.2%17%18.4%
2 Days20.2%11.2%7.1%5.1%6.3%5.0%
3 Days12.9%8.7%4.5%4.8%5.0%4.7%
4 Days10.9%6.0%3.4%3.3%4.1%3.5%
5 Days7.5%6.5%2.9%3.2%5.5%2.0%
> 5 Days7.1%3.9%2.7%2.6%2.8%2.3%
Data Source: CERT Report Table B7

 OIG Focus on Short Inpatient Stays after implementation of the Two-Midnight Rule

One year after implementation of the Two-Midnight Rule, the OIG included the item: New Inpatient Admission Criteria in their FY 2015 Work Plan. Specifically, the OIG indicated that they “will determine the impact of new inpatient admission criteria on hospital billing, Medicare payments, and beneficiary copayments. This review will also determine how billing varied among hospitals in FY 2014. Previous OIG work identified millions of dollars in overpayments to hospitals for short inpatient stays that should have been billed as outpatient stays. Beginning in FY 2014, new criteria state that physicians should admit for inpatient care those beneficiaries who are expected to need at least 2 nights of hospital care (known as the “two midnight policy”). Beneficiaries whose care is expected to last fewer than 2 nights should be treated as outpatients. The criteria represent a substantial change in the way hospitals bill for inpatient and outpatient stays.”  

For the FY 2016 Work Plan, the OIG followed up with a slightly different look at short stay reviews, the item, Hospitals’ use of outpatient and inpatient stays under Medicare’s two-midnight rule. The OIG noted that they “will determine how hospitals’ use of outpatient and inpatient stays changed under Medicare’s two-midnight rule, as well as how Medicare and beneficiary payments for these stays changed, by comparing claims for hospital stays in the year prior to the effective date of the two-midnight rule to stays in the year following the effective date of that rule. We will also determine the extent to which the use of outpatient and inpatient stays varied among hospitals. CMS implemented the two-midnight rule on October 1, 2013. This rule represents a substantial change to the criteria that hospital physicians are expected to use when deciding whether to admit beneficiaries as inpatients or treat them as outpatients.

On December 19, 2016, the OIG published the Report Vulnerabilities Remain Under Medicare's 2-Midnight Hospital Policy. They noted in the report that while they “found that the number of inpatient stays decreased, the number of outpatient stays increased since the implementation of the 2-midnight policy. Further, short inpatient stays decreased more than long outpatient stays. Despite these changes, vulnerabilities still exist.

  • Hospitals are billing for many short inpatient stays that are potentially inappropriate under the policy; Medicare paid almost $2.9 billion for these stays in FY 2014.
  • Medicare pays more for some short inpatient stays than for short outpatient stays, although the stays are for similar reasons.
  • Hospitals continue to bill for a large number of long outpatient stays.
  • An increased number of beneficiaries in outpatient stays pay more and have limited access to SNF services than they would as inpatients.
  • Hospitals continue to vary in how they use inpatient and outpatient stays.”

Here we are in December of 2020 and hospitals have been put on notice as the OIG once again targets short stay reviews. They note in this new Work Plan item that “Prior OIG audits identified millions of dollars in overpayments for inpatient claims with short lengths of stay. Instead of billing the stays as inpatient claims, they should have been billed as outpatient claims, which usually results in a lower payment. To reduce inpatient admission errors, CMS implemented the Two-Midnight Rule in fiscal year 2014. Under the Two-Midnight Rule, CMS generally considered it inappropriate to receive payment under the inpatient prospective payment system for stays not expected to span at least two midnights. The only procedures excluded from the rule were newly initiated mechanical ventilation and any procedures appearing on the Inpatient Only List. Revisions were made to the Two-Midnight Rule after its implementation. We plan to audit hospital inpatient claims after the implementation of and revisions to the Two-Midnight Rule to determine whether inpatient claims with short lengths of stay were incorrectly billed as inpatient and should have been billed as outpatient or outpatient with observation. We also plan to review policies and procedures for enforcing the Two-Midnight Rule at the administrative level and contractor level. While OIG previously stated that it would not audit short stays after October 1, 2013, this serves as notification that the OIG will begin auditing short stay claims again, and when appropriate, recommend overpayment collections.” The expected issue date of their findings is FY 2021.


Moving Forward: Compliance with Short Stay

In general, for any given review target, hospitals with high volume and or high paid claims tend to be subject to medical review. Questions to ask and find answers to moving forward:

  • Do you track your short stay volume overall, by MS-DRG or Physician over time?
  • Do you know what percentage of your Medicare Fee-for-Service inpatient claims are for short stays?
  • If so, is this subset of your overall claims increasing year over year at your facility?
  • Does the documentation in short stay medical records support a short stay inpatient admission?
  • Do you know if your hospital is an outlier?
  • Where can you look to find these answers?



One resource available to hospitals is the Short-Term Acute Care PEPPER (Program for Evaluating Payment Patterns Electronic Report). The PEPPER is made available to hospitals on a quarterly basis and compares your hospital to your state, MAC Jurisdiction and the nation. One-day Stays for Medical and Surgical MS-DRGs are two of the “Target Areas” at risk for improper payments included in this report.

The PEPPER Short-Term Acute Care Hospitals User's Guide provides the following suggested interventions for high One-day Stays Hospitals: 

“This could indicate that there are unnecessary admissions related to inappropriate use of admission screening criteria or outpatient observation. A sample of same- and/or one-day stay cases should be reviewed to determine if inpatient admission was necessary or if care could have been provided more efficiently on an outpatient basis (e.g., outpatient observation). Hospitals may generate data profiles to identify same- and/or one-day stays sorted by DRG, physician or admission source to assist in identification of any patterns related to same- and/or one-day stays. Hospitals may also wish to identify whether patients admitted for same- and/or one- day stays were treated in outpatient, outpatient observation or the emergency department for one or more nights prior to the inpatient admission. Hospitals should not review same- and/or one- day stays that are associated with procedures designated by CMS as “inpatient only.”


RealTime Medicare Data

Another source that can help assist you is our sister company, RealTime Medicare Data (RTMD). RTMD collects over 1.2 billion Medicare claims annually from 48 states and the District of Columbia, and allows for searching of over 10 billion historical claims and counting.

In response to the “Two-Midnight” Policy, RTMD has available in their suite of Inpatient Hospital reports a One Day Stay Report. To give you a true picture of your “at risk” volume, this report excludes claims with a discharge status for Expired (20), left against medical advice (07), hospice (50 & 51) and /or were transferred to another Acute care facility (02). This report enables a hospital to view one day stay paid claims data by DRG and Physician to direct where audits should be focused. For further information on all that RTMD has to offer you can visit their website at

Article Author: Beth Cobb, RN, BSN, ACM, CCDS
Beth Cobb, RN, BSN, ACM, CCDS, is the Manager of Clinical Analytics at Medical Management Plus, Inc. Beth has over twenty-five years of experience in healthcare including eleven years in Case Management at a large multi-facility health system. In her current position, Beth is a principle writer for MMP’s Wednesday@One weekly e-newsletter, an active member of our HIPAA Compliance Committee, MMP’s Education Department Program Director and co-developer of MMP’s proprietary Compliance Protection Assessment Tool.

This material was compiled to share information.  MMP, Inc. is not offering legal advice. Every reasonable effort has been taken to ensure the information is accurate and useful.