Selection Criteria for Heart Failure Patients
Of those with a documented ICD-9-CM code 428.00, patients included were those with 3 or more office visits with heart failure documented in the assessment (suspected heart failure) and for whom another competing diagnosis for volume overload was not later determined (verified heart failure). Of the 420 patients with a billing diagnosis of heart failure, 25 had insufficient documentation in the medical record. Thus, data from 395 records were studied for compliance with the diagnostic criteria for heart failure, as these records reflected physician suspicion of the condition during at least 3 visits. Of these, an additional 57 patient charts were excluded, because an etiology for volume overload was found other than simple left ventricular failure. These records included those patients with valvular heart disease and those with volume overload due to noncardiac etiologies. Thus, we assessed 338 medical records documenting sustained management of heart failure by the primary care physician for their compliance with the treatment review criteria. We report this data for 2 subgroups according to left ventricular ejection fraction (LVEF) test result, to differentiate systolic heart failure from diastolic and unclassified heart failure.
Measures Used
Initially we developed 4 review criteria9 using a measurement validity method described by Palmer and colleagues.10 This method is a systematic and rigorous approach for translating guideline recommendations into measurable review criteria. We expanded our data collection to test 5 additional criteria recommended by researchers at RAND11Table 1. Three of the 9 criteria focused on the diagnosis of heart failure and education; 6 measured pharmacologic management and monitoring of patients known to have systolic heart failure defined as an LVEF 40%. Two of these criteria (laboratory tests and patient counseling) had multiple measures, making a total of 17 adherence measures. Patients’ cardiac functional status was assessed by asking each primary physician to rate their patients using the New York Heart Association (NYHA) classification system.14 Responses were returned no later than October 1997.
Medical Record Review
In 1996, a separate study enabled the development and testing of the chart extraction form using 99 patients in 4 practices. Minor revisions were made on the basis of recommendations from the nurse chart extractors and the participating physicians. The revised medical record reviews took an average of 1 hour and 15 minutes to complete. They included any data found within the office medical record, such as medication lists, problem lists, progress notes, consultation letters, hospital discharge data, emergency department visits, laboratory results, radiographic data, and old records from other physicians.
The chart extractors first collected data related to the initial date of diagnosis. Next, they recorded all LVEF tests, emergency department visits, and hospitalizations that occurred between the date of initial diagnosis and the date of the medical record review. Finally, between either January 1, 1994, or the date of diagnosis (whichever date was more recent) and the date of the medical record review, all progress notes for office visits were examined for documentation of heart failure evaluation, medications prescribed, and test use. This period provided a potential for 3 years of follow-up. Chart review occurred from December 1996 through March 1997.
To evaluate consistency across reviewers, a second blinded record review was completed using 45 patient records selected randomly. The k statistic was estimated to assess interrater reliability for each review criterion. For these analyses, only the 8 measures (representing 5 criteria) with a k Ž0.4 were used for analyses of adherence. The highest ratios were for the measurement of LVEF (0.57), measurement of renal function (0.63), prescribed trial of angiotensin-converting enzyme (ACE) inhibitors (0.80), and ACE inhibitor at target dose (0.72). In addition to this assessment of data quality, the chart extraction manager evaluated each extraction form; any questionable or missing information was verified during a follow-up chart review.
Analyses
The unit of analysis for both research questions was at the patient level, and weighted performance rates are reported for the total population of heart failure patients in the 25 practices. Initial plans to analyze performance at the physician and practice levels were hindered by the small number of patients in each practice. Seven of the 25 practices had · 10 patients with evidence of heart failure; 13 practices had 11 to 25 patients. Recent evidence suggests that performance rates lack stability with such small numbers.15 Weighted adherence rates were calculated to adjust for the systematic sampling in the 5 larger practices.
For the first research question (How many heart failure patients found through claims data are actually eligible for measuring quality of care in accordance with an evidence-based guideline for systolic dysfunction?), we calculated the adjusted percentages of patients listed in the administrative datasets who had evidence of heart failure in the chart (more than 3 visits with documentation), had verified heart failure, and had confirmed systolic heart failure (LVEF · 40%). For the second research question (What are the adherence rates to specific measurable review criteria among this sample of primary care physicians?), we used several denominators for the various review criteria. For the 3 diagnostic criteria, we used the estimated total number of patients who had evidence of heart failure documented in their charts. For the first ACE inhibitor review criterion, we evaluated performance separately among the systolic heart failure patients and all other heart failure patients (those with a normal LVEF or no LVEF documented). For the second ACE inhibitor criterion (evaluating dosages), the denominator was the estimated number of patients taking the drug at the time of the chart review.