HICPAC’s key points on case finding, risk adjustment

HICPAC’s key points on case finding, risk adjustment

Template addresses difficult areas

The Centers for Disease Control and Prevention’s (CDC) Healthcare Infection Control Practices Advisory Committee (HICPAC) recently released a template document for officials seeking to establish infection rate disclosure laws.¹ Key recommendations in the areas of patient populations, case finding, and risk adjustment are summarized as follows:

• Identifying Patient Populations for Monitoring. CDC and other authorities no longer recommend collection or reporting of hospitalwide overall health care-associated infection (HAI) rates because rates are low in many hospital locations (which makes routine inclusion of these units unhelpful); collecting hospitalwide data is labor-intensive and may divert resources from prevention activities; and methods for hospitalwide risk adjustment have not been developed. Rather than hospitalwide rates, reporting rates of specific HAIs for specific hospital units or operation-specific rates of surgical-site infection (SSI) is recommended. This practice can help ensure data collection is concentrated in populations where HAIs are more frequent and rates that are calculated are more useful for targeting prevention and making comparisons among facilities or within facilities over time.
• Case Finding. Once the population at risk for HAIs has been identified, standardized methods for case finding should be adopted. Such methods help reduce surveillance bias (i.e., the finding of higher rates at institutions that do a more complete job of case finding). Incentives to find cases of HAI may be helpful. Conversely, punitive measures for hospitals that report high rates may encourage underreporting. Traditional case-finding methods for HAIs include review of medical records, laboratory reports, and antibiotic administration records. However, these standard case-finding methods can be enhanced. For example, substantially more SSIs are found when administrative data sources (e.g., International Classification of Diseases, 9th Revision [ICD-9], discharge codes) are used in combination with antimicrobial receipt to flag charts for careful review. However, the accuracy of case finding using ICD-9 codes alone likely varies by HAI type and by hospital. Therefore, ICD-9 discharge codes should not be relied upon as the sole source for HAI monitoring systems.
• HAI Rates and Risk Adjustment. For optimal comparison purposes, HAI rates should be adjusted for the potential differences in risk factors. For example, in CDC sentinel surveillance, device-associated infections are risk adjusted by calculating rates per 1,000 device-days and stratifying by unit type. Similarly, risk adjustment of SSIs is done by calculating of operation-specific rates stratified by a standardized risk index. Although these methods do not incorporate all potential confounding variables, they provide an acceptable level of risk adjustment that avoids the data collection burden that would be required to adjust for all variables. Risk adjustment is labor-intensive because data must be collected on the entire population at risk (the denominator) rather than only the fraction with HAIs (the num-erator). Risk adjustment cannot correct for variability among data collectors in the accuracy of finding and reporting events. Further, current risk-adjustment methods improve but do not guarantee the validity of interhospital comparisons, especially comparisons involving facilities with diverse patient populations (e.g., community vs. tertiary-care hospitals). Valid event rates are facilitated by selecting events that occur frequently enough and at-risk populations that are large enough to produce adequate sample sizes. Unfortunately, use of stratification (e.g., calculation of rates separately in multiple categories) for risk adjustment may lead to small numbers of HAIs in any one category and thereby yield unstable rates, as is the case of a small hospital with low surgical volume.

Reference

1. Centers for Disease Control and Prevention. Guidance on Public Reporting of Health Care-Associated Infections Recommendations of the Healthcare Infection Control Practices Advisory Committee. Web: www.cdc.gov/ncidod/hip/PublicReportingGuide.pdf.