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Validating a Measure of Hypertension Care Using Administrative Databases
Dan R. Berlowitz, MD MPH
VA Bedford HealthCare System, Bedford, MA
Funding Period: April 2000 - September 2001
Hypertension affects over 20 percent of adults, with most patients poorly controlled, resulting in excess morbidity. Thus, improving hypertension care is critical. While many processes of care are important in delivering high quality hypertension care, the critical process in achieving good blood pressure (BP) control is likely to be clinician management of anti-hypertensives. We recently developed a novel approach for measuring intensity of anti-hypertensive therapy and applied it to the problem of BP control. Those receiving more intensive therapy had better BP control. This measure could be used in profiling clinician practices and promoting practice improvements. However, our work was limited since it was based on paper medical records and included only 800 patients. Clinical information available from VA databases has increased in recent years. These data could be used in our therapy intensity measure.
Objectives are: 1) to examine availability, reliability, and validity of key data elements used in modeling clinician practices with anti-hypertensives; 2) to validate our previous model for predicting changes in anti-hypertensives using information in existing VA databases.
At each of 10 VA sites, we randomly selected approximately 100 patients with a diagnosis of hypertension receiving regular medical care. We undertook a retrospective chart review for the period January 1 to December 31, 1999, abstracting data on visit type, BP, medications and diagnoses. We will compare BP measurements, diagnoses, and prescribed anti-hypertensives described in VISTA databases and the OPC with information derived from clinicians’ notes. We will evaluate whether BPs from outpatient medical visits are recorded in the database, whether hypertension-related diagnoses are accurately captured, and whether changes in anti-hypertensives described in the database can be accurately assigned to a clinic visit. Next, we will validate our model predicting therapy changes in this new study sample and with this new data source. We will determine whether the model continues to discriminate among patients at different probability of having a therapy increase and whether simple model modifications improve its performance.
Objective 1: data collection and chart abstractions have been completed at all 10 sites. Preliminary analyses suggest that detailed information on BP control is available at these sites; of 4620 visits, 71 percent had at least one BP in VISTA; only 38 percent had a BP in clinicians’ notes and only 27 percent had a BP from both sources. Data analysis for objective 1 is nearing completion. Objective 2: data collection is nearing completion.
This project represents an important intermediate step in our plans for developing a quality measurement and improvement program for hypertension care in the VA. Specifically, we will learn whether necessary data are available and whether these data can be used to model the decision to change anti-hypertensive medication therapy. Subsequent studies will then be able to profile hypertension care in the VA using readily available data sources.
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DRA: Health Systems
DRE: Technology Development and Assessment
Keywords: Cardiovasc’r disease, Pharmaceuticals, Quality assessment
MeSH Terms: none