Finally Present on Admission but Needs Attention

Abstract

Momentum has finally gathered for a long-overdue addition to coding of hospital discharge diagnoses using the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM): indicating whether or not discharge diagnoses were when patients were admitted to hospitals. The present on (POA) indicator could greatly increase the utility of discharge diagnoses for various administrative, quality assurance, and research purposes. For many years, the primary rationale focused on using POA indicators for quality screening and monitoring, under the presumption that conditions that newly arise during hospital stays might possibly be more likely to represent complications and potential quality problems (yes, the wordy equivocation is intentional). POA indicators could particularly inform risk adjustment of hospital outcomes like mortality rates, specifically eliminating diagnoses representing hospitalacquired complications from risk-adjustment algorithms. In June 1992, the National Committee on Vital and Health Statistics (NCVHS) proposed multiple changes to the Uniform Hospital Discharge Data Set (UHDDS; the data required for all acute hospital discharges reimbursed by Medicare and Medicaid since 1974). Among several proposals for new UHDDS data elements, NCVHS suggested adding an alpha POA qualifier to each discharge diagnosis. NCVHS based this proposal on experiences at Mayo Clinic and in New York state, where POA indicators added modest additional to data collection.1 A dozen years later, NCVHS again recommended adding a discharge diagnosis modifier/flag for POA, this time specifically proposing modifications to UB-04 (the uniform bill submitted by hospitals) and the ANSI X12N Implementation Guide.2 The federal government never adopted NCVHS's proposals. Recent Medicare policy mandates have made adding POA indicators suddenly urgent. The Deficit Reduction Act of 2005 requires Medicare to stop paying hospitals for the costs of treating certain infections that occur in-hospital starting in October 2008. POA indicators offer the only feasible option to support this new mandate.3 Standard hospital bills already contain ICD-9-CM discharge diagnosis codes required to assign diagnosisrelated groups (DRGs), which determine Medicare hospital reimbursement levels. Effective March 1, 2007, UB-04 adds fields for POA indicators for discharge diagnoses, using standard coding guidelines.4 By definition, principal diagnoses are generally on admission inasmuch as they caused the hospitalization, but ICD-9-CM coding conventions require that a few conditions not POA be recorded as principal (eg, V codes for chemotherapy). Therefore, UB-04 has POA slots for both principal and secondary diagnoses. (The POA concept does not apply to certain ICD-9-CM codes, such as V codes for personal history of malignant neoplasm; coding guidelines exempt such codes from requiring POA indicators.3) These UB-04 changes apply to the paper form of the bill; modifications for electronic claims submission, used by the majority of providers, are still required. In this issue of Medical Care, Zhan et al5 demonstrate how POA indicators might alter Medicare payments for hospitalizations. Using hospital claims from California and New York, which have had POA indicators for over a decade, they assigned DRGs using all diagnoses and then again using only POA diagnoses. Relatively few cases (1 .4%) shifted to lower cost DRGs using only POA diagnoses for DRG assignment, and projected nationwide cost savings were