Background: The Prevention Index is a methodology for using electronic medical records to identify and evaluate practice variations in the delivery of preventive care.
Methods: The Prevention Index was used to evaluate the provision of 10 recommended adult preventive services using electronic medical record data for the years 1999 through 2002 among the 450,000 members of a large Northwest integrated care system. The analyses were conducted in 2005. The Prevention Index determines the proportion of person-time that is covered using consensus guidelines as a standard of care. It is analyzed at the population level and produces quality measures at the individual, practice, clinic, and system levels. The Prevention Index also removes diagnostic services in evaluating preventive care.
Results: Overall, about 47% of recommended person-time was actually covered by the services in 2002. For nine services with care guidelines, the percent of covered person-time ranged from 19% for chlamydia screening to 80% for blood pressure screening. The percent of recommended person-time covered by these preventive services varied widely across clinical practices. From 17% to 53% of preventive screening tests were delivered for non-screening purposes.
Conclusions: There are wide variations across clinical practices in the adherence to standard prevention guidelines, and also wide variations across different recommended clinical services. The Prevention Index methodology may allow the identification of the source of these variations, allowing system corrections and other remedial actions to be applied precisely and efficiently.