Results
Tests of 2 proportions were run for the 2 pharmacologic review criteria to determine if the performance rates were significantly higher in the systolic heart failure group than with all other heart failure patients. Also, chi-square tests and comparison-of-mean t tests were conducted to compare descriptors of heart failure presentation and specific comorbidities between these 2 groups (using the original unadjusted sample).
Patient Characteristics in Cohort
The average age of the patients was 76 years (± 11 years), with nearly one fourth of the sample aged 85 years or older. Although nearly half (48%) of the patients had been given their diagnosis less than 2.5 years before the chart-review period, almost one fourth (24%) had received the diagnosis more than 5 years ago. The prevalence of comorbidities was high among these patients. Eighty-six percent of the sample had one or more diseases associated with heart failure. Chronic obstructive pulmonary disease, diabetes, and arthritis were documented in approximately one third of the patient medical records (29%, 35%, and 32%, respectively).
The comparison of heart failure presentation descriptors and comorbidities is presented in Table 2. Systolic heart failure patients were younger at the time of diagnosis and were less likely to have arthritis or osteoporosis listed as a comorbidity. Although the prevalence of coronary artery disease was statistically similar in the 2 groups, significantly more (P = .01) of the systolic heart failure patients had a history of myocardial infarction (55% of patients with low LVEF vs 45% among the others). In all other comparisons, including NYHA functional classification, no difference was found between the groups.
Accuracy of Administrative Databases
Of 740 patients in the billing database with the ICD-9-CM code for heart failure, the adjusted number with suspected heart failure was 661 (89%). Only 572 (77%) had verified heart failure by clinical criteria. In the study sample, a low LVEF consistent with systolic heart failure was found for only 142 patients (37% of those with documented evidence of heart failure), though a normal LVEF was found for an equal number of patients (n = 145, 37%). Thus, we estimate only 31% of all patients labeled with heart failure in administrative databases in these 25 practices had documented systolic dysfunction.
Diagnostic Criteria
The adjusted performance rates based on our weighted sampling for the diagnostic review criteria are presented in Table 3. Within 3 months before or following diagnosis, 60% of all suspected heart failure patients (n = 661 estimated) had a measure of LVEF documented. This rate increased to 67% for the time interval of 6 months before or after diagnosis. When any time frame was disregarded, we found that 82% had an LVEF test documented in the medical record.
Higher adherence rates would have been found for use of LVEF if we had used more specific criteria. Of 72 charts reviewed that did not have any documentation of an LVEF measure,13 (18%) showed the test had been ordered but no documentation of the result. Physicians were queried about LVEF testing for the remaining patients. They reported another 10 (14%) patients had LVEF measures taken while in the hospital and 8 (11%) patients refused the test. For our study these 31 patients were all grouped in the nonadherence category. Those patients without any LVEF measurement were significantly older (82 vs 75 years; t test P< .001) and had fewer comorbidities (average = 2.6 vs 3.5; t test P <.001) than patients who had the test.
Measuring initial laboratory evaluation was complicated by uncertainty about the time of diagnosis, place of diagnosis, and the time frame chosen for compliance. Thus, several review criteria had low ks (< 40%) and were not reported. For laboratory evaluation, performance rates ranged from a low of 30% for thyroid function to a high of 72% for renal function tests. Documentation of patient education about diet changes was also low (21% compliance). However, low compliance should be interpreted with caution, as medical record review has been found to be unreliable in assessing patient education.16
Treatment Review Criteria
The performance rates for treatment review criteria are shown in Table 3. The adjusted rate of ACE inhibitor use in all patients with a diagnosis of heart failure was 74% (n = 421). We report data for compliance with each class of heart failure to illustrate the importance of documenting a low LVEF. The adjusted adherence rate was significantly higher for systolic heart failure patients (91%) than for patients with normal LVEFs or no LVEF measured (62%) (for the test of the difference between 2 population proportions z = 7.88, P <.001). The performance rates for achieving the target dosages were also significantly different in the 2 groups (z = -2.38; P <.01). Eighty-seven percent of the estimated number of systolic heart failure patients taking an ACE inhibitor at the time of the chart audit (n = 421 adjusted and estimated) were achieving the target dose, compared with 94% of the other patients. The 95% confidence interval for this performance rate in the systolic heart failure group did overlap the proposed standard of quality. Of the 267 patients in the initial sample who had been prescribed a trial of ACE inhibitors,37 (11%) met exclusion criteria for not taking one at the time of the chart review.