Freeman Spogli Institute for International Studies Program on Energy and Sustainable Development Stanford University


Measures of Patient Safety Based on Hospital Administrative Data: The Patient Safety Indicators

Evidence Report

Kathryn M. McDonald, PS Romano, Jeffrey J. Geppert, Sheryl M. Davies, Brad Duncan, KG Shojania, Angela Hansen

Published by
University of California San Francisco-Stanford Evidence-Based Practice Center under contract no. 290-97-0013. Agency for Healthcare Research and Quality, Rockville, Maryland, August 2002
Publication no. 02-0038; Technical Review no. 5

Objectives. Concerns have mounted about the complexities of the health care system potentially causing significant unintended adverse effects. With a major national interest in addressing patient safety issues, a wide spectrum of individuals and organizations are working toward developing methods and systems to detect, characterize, and report potentially preventable adverse events. One approach is to develop screening measures based on routinely collected administrative data, such as the patient safety indicators (PSIs) reported here. The purpose of the PSI project is to report 1) literature-based evidence on potential PSIs, 2) clinician panel review results of potential indicators, 3) empirical analyses on a subset of indicators, and 4) recommendations regarding potential PSIs.

Methods. A four-pronged strategy to collect validation data and descriptive information was used: 1) background literature review, 2) structured clinical panel reviews of candidate PSIs, 3) expert review of ICD-9-CM codes in candidate PSIs, and 4) empirical analyses of the potential candidate PSIs. Evidence from these four sources was used to modify and select the most promising indicators for use as a screening tool to provide an accessible and low-cost approach to identifying potential problems in the quality of care related to patient safety.

Main results. A review of previously reported measures in the literature, and of medical coding manuals, resulted in identification of over 200 ICD-9-CM codes representing potential patient safety problems. Most of these codes were grouped into clinically meaningful indicators either based on previous indicator definitions or on clinical and coding expertise. Based on literature review of the published evidence related to their validity, several potential PSIs were eliminated. Because of the limited validation literature available on PSIs and complications indicators from which many PSIs were derived, the research team conducted a clinical panel review process to assess the face validity and to guide refinements to the initial definitions of the 34 most promising PSIs. Response to a questionnaire by clinicians (i.e., physicians from a number of specialties, nurses, and pharmacists) for each indicator, augmented by coding review and initial empirical testing, provided the basis for selecting the indicators expected to be most useful for screening for potentially preventable adverse events. Twenty hospital level PSIs are recommended for implementation as the initial AHRQ PSI set (designated Accepted indicators).

Conclusions and future research. Future validation work should focus on the sensitivity and specificity of these indicators in detecting the occurrence of a complication; the extent to which failures in processes of care at the system or individual level are detected using these indicators; the relationship of these indicators with other measures of quality, such as mortality; and further explorations of bias and risk adjustment. Enhancements to administrative data are worth exploring in the context of further validation studies that utilize data from other sources. The current development and evaluation effort will best be augmented by a continuous communication loop between users of these measures, researchers interested in improving these measures, and policy makers with influence over the resources aimed at data collection and patient safety measurement.