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Temporal Trends (1986-1997) in Cholesterol Level Assessment and Management Practices in Patients With Acute Myocardial Infarction
A Population-Based Perspective
Jorge Yarzebski, MD, MPH;
Frederick Spencer, MD;
Robert J. Goldberg, PhD;
Darleen Lessard, MS;
Joel M. Gore, MD
Arch Intern Med. 2001;161:1521-1528.
ABSTRACT
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Background Elevated serum cholesterol levels are associated with increased risk
for acute myocardial infarction (AMI) and adverse patient outcomes. It is
unclear what proportion of patients have their serum cholesterol levels measured
during hospitalization for AMI and are given hypolipidemic therapy.
Objective To examine decade-long trends in measurement of serum cholesterol levels
during hospitalization for AMI and use of hypolipidemic therapy.
Methods Observational study of 5204 residents of the Worcester, Mass, metropolitan
area hospitalized with validated AMI in all greater Worcester hospitals in
seven 1-year periods from 1986 through 1997.
Results Increases in the measurement of serum cholesterol levels during hospitalization
for AMI were observed between 1986 and 1991, followed by a progressive decrease;
only 24% of patients with AMI in 1997 underwent cholesterol level testing.
Younger age, male sex, and absence of a history of cardiovascular disease
were associated with an increased likelihood measurement of serum cholesterol
levels. Although the relative use of hypolipidemic therapy increased significantly
over time (0.4% in 1986 vs 10.7% in 1997), the absolute rate of use remained
low. In patients with elevated serum cholesterol levels ( 6.2 mmol/L [240
mg/dL]), 1.9% received hypolipidemic therapy in 1986 and 36.6% in 1997.
Conclusions These findings suggest recent declines in the assessment of total cholesterol
levels in patients hospitalized with AMI. Although the use of hypolipidemic
therapy during hospitalization for AMI has increased over time, considerable
room for improvement remains.
INTRODUCTION
ONE OF THE MOST important risk factors for coronary heart disease (CHD)
is an elevated total blood cholesterol level.1
Elevated serum cholesterol levels are associated with progression of coronary
artery disease in patients with angiographically confirmed disease2-3 and with an increased risk for recurrent
coronary events and all-cause mortality in patients with acute myocardial
infarction (AMI).4 The results of a large number
of clinical trials have provided convincing evidence that intervention with
hypolipidemic drugs is associated with a reduced risk for CHD events, mortality,
and use of health care services.5-9
Based on these and additional findings, guidelines and indications for the
treatment of patients with elevated total and low-density lipoprotein (LDL)
cholesterol levels have been published.10-12
Despite the development and dissemination of these guidelines and calls
for more widespread application of dietary and hypolipidemic therapy in high-risk
patients and those with confirmed CHD, multiple studies suggest that these
therapeutic approaches remain underused.13-15
Accordingly, a number of health care organizations have identified the measurement
and subsequent treatment of elevated serum cholesterol levels, specifically
LDL cholesterol, as a benchmark of quality health care in patients with recent
AMI. The National Committee for Quality Assurance has recently implemented
a performance measure that reflects the effectiveness of cholesterol level
management in patients with CHD. Managed care organizations currently looking
for accreditation from the National Committee for Quality Assurance must act
in accord with the latest measure of the Health Plan Employer and Data Information
Set. This measure mandates the assessment and report of the proportion of
patients with major CHD events in whom LDL cholesterol levels of less than
3.4 mmol/L (<130 mg/dL) have been achieved within 2 months to 1 year after
hospital discharge.16
The appropriate timing of lipid level measurements after AMI has also
been the subject of controversy.17-18
Indeed the 1993 guidelines from the National Cholesterol Education Program
Adult Treatment Panel II (NCEP ATP II) suggested delaying baseline assessment
and treatment of lipid levels until 6 weeks after AMI.11
Unfortunately, postponing the measurement of serum lipid levels in patients
with acute coronary events until after hospital discharge will lead to missed
opportunities for the identification and treatment of this important coronary
prognostic factor. This concern prompted the American Heart Association Task
Force on Risk Reduction to call for the immediate measurement of serum lipid
levels in patients admitted to the hospital for AMI.19
The purpose of the present study was to examine, from a multihospital,
communitywide perspective, decade-long trends in the practices of cholesterol
level assessment and the institution of hypolipidemic therapy in patients
with confirmed AMI. The study sample consisted of residents of greater Worcester,
Mass, admitted to all hospitals in the Worcester metropolitan area in seven
1-year periods from between 1986 and 1997 with validated AMI.
MATERIALS AND METHODS
The population under study consisted of metropolitan Worcester residents
hospitalized with validated AMI in 16 university-affiliated and community
hospitals in the Worcester metropolitan area during 1986, 1988, 1990, 1991,
1993, 1995, and 1997. Fewer hospitals were included in recent years because
of hospital closures or their conversion to chronic care or rehabilitation
facilities. The methods of sample identification and diagnostic criteria used
in this study have been described in detail previously.20-22
In brief, to be considered for study inclusion, patients had to be residents
of the Worcester metropolitan area (1990 census estimate, 437 000) and
have at least 2 of 3 predefined criteria consistent with AMI. Determination
of eligibility was based on the review of medical records of patients hospitalized
with a primary or secondary discharge diagnosis of AMI (International Classification of Diseases, Ninth Revision [ICD-9] code 410) and other possible discharge diagnoses in which AMI
may have been misclassified (ICD-9 codes 411-414
and 786.5) at all Worcester metropolitan area hospitals. These criteria included
a typical history of prolonged chest pain (ie, lasting >20 minutes) not relieved
by rest and/or use of nitrates, peak serum enzyme level elevations above normal
hospital values, and serial electrocardiographic tracings during hospitalization
showing evolutionary changes in the ST segment and/or Q waves typical of AMI.20-22
A total of 5998 residents of greater Worcester sustained a validated
AMI during the 7 study years. Information about measurement of a more complete
serum lipid-level profile (eg, triglycerides and high-density lipoprotein
[HDL] and LDL cholesterol) was available only for patients hospitalized in
1995 and 1997; their characteristics were not examined in this study, as the
primary focus of this report was the measurement of total serum cholesterol
levels. Patients receiving hypolipidemic medication before the index hospitalization
(n = 403), those transferred from other hospitals (n = 406), and those whose
serum cholesterol levels were considered to be elevated due to laboratory
measurement error (n = 13) were excluded from further consideration. After
these exclusions, 5204 patients constituted the sample of interest. (Some
patients met more than 1 of the exclusion criteria.)
DATA COLLECTION
The medical records of hospitalized residents were individually reviewed
and validated according to the preestablished diagnostic criteria. Information
about demographics, medical history, clinical characteristics, the use of
various therapies before and during the acute hospitalization, and therapy
prescribed at the time of hospital discharge was abstracted from the medical
records of geographically eligible patients satisfying the study inclusion
criteria. Prescription of hypolipidemic medications during hospitalization
for AMI and/or at the time of hospital discharge was ascertained through the
review of notes by physicians and nurses indicating the use of any hypolipidemic
medication during the index event. Total serum cholesterol levels were measured
in automated clinical chemistry analyzers at the laboratories of participating
hospitals.
DATA ANALYSIS
Demographics, medical history, and clinical factors associated with
test-ordering practices for cholesterol level measurement and changes over
time therein were examined in the study sample. Analysis of variance was used
to examine differences between various comparison groups for continuous variables,
whereas  2 tests of statistical significance were used for
the analysis of differences in discrete variables. All tests of statistical
significance were 2-tailed. Multivariable regression analyses were used to
examine the association between whether total serum cholesterol levels were
measured during hospitalization for AMI and demographic characteristics, medical
history, and clinical factors.
RESULTS
SAMPLE CHARACTERISTICS
The mean age of the study sample was 68 years; 59.2% of the subjects
were men. A history of angina was present in 24.4%; diabetes, in 26.1%; and
hypertension, 52.0%. An initial AMI was present in 68.0% of the sample, and
a Q-wave MI developed in 44.6% during the index hospitalization.
OVERALL AND DECADE-LONG TRENDS IN THE MEASUREMENT OF TOTAL SERUM CHOLESTEROL
LEVELS
A total of 3067 (58.9%) patients had their total cholesterol level measured
during hospitalization for AMI between 1986 and 1997. Trends in serum cholesterol
level measurement during the index hospitalization are shown in Figure 1. Measurement of total cholesterol levels increased markedly
from 1986 through 1991, after which time a significant decline occurred such
that slightly less than one quarter of patients with AMI hospitalized in 1997
had their serum cholesterol levels measured. Overall, 72.7% of those patients
who had their total cholesterol levels measured did so during the first day
of hospitalization (76.0% in 1986 vs 40.8% in 1997). In 1995, 9.1% of patients
had a complete lipid-level profile performed (triglycerides and HDL and LDL
cholesterol), whereas 15.0% of patients had a complete profile performed in
1997.
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Figure 1. Trends in total cholesterol level
measurement during hospitalization for acute myocardial infarction in the
Worcester, Mass, Heart Attack Study.
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CHARACTERISTICS OF PATIENTS ASSOCIATED WITH ORDERING PRACTICES FOR
TOTAL CHOLESTEROL LEVELS
The demographic characteristics, medical history, and clinical characteristics
of patients with AMI according to whether a total serum cholesterol level
measurement was performed are shown in Table 1. These data are presented for the total study sample and
stratified according to several aggregated periods to make trends over time
more interpretable. During the combined periods, total cholesterol level was
significantly more likely to be measured during the acute hospitalization
in younger patients, men, and patients without selected comorbidities. Patients
with an initial Q-wave AMI were also significantly more likely to have assays
of cholesterol levels performed than patients with a previous or non–Q-wave
MI.
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Table 1. Characteristics of Patients With AMI According to Serum Cholesterol
Level Measurement Practices and Study Period*
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Trends in the relationship of these demographic and clinical factors
to the measurement of serum cholesterol levels in the 3 aggregated periods
under study are also shown (Table 1).
Despite differences over time in the absolute number and proportion of patients
having their serum cholesterol level measured, the association of selected
factors with the measurement of serum cholesterol level was relatively similar
during the periods under study.
FACTORS ASSOCIATED WITH SERUM CHOLESTEROL LEVEL MEASUREMENT DURING
HOSPITALIZATION FOR AMI
Several multivariable regression analyses were performed to examine
the association of selected patient characteristics with the measurement of
total cholesterol level in patients with AMI overall as well as during the
earliest (1986-1988) and most recent (1995-1997) study periods. The independent
factors controlled for in these analyses included patient age; sex; medical
history of angina, diabetes, hypertension and/or stroke; and AMI-associated
characteristics (Table 2). The
results of this analysis in the total study sample showed that the likelihood
of having total cholesterol level measured during the index hospitalization
declined with advancing age and was significantly more likely to be performed
in patients with Q-wave AMI. Patients with a history of diabetes and hypertension
were significantly less likely to have their total cholesterol level measured
than were patients without these conditions. During the earliest study period
(1986-1988), measurement of serum cholesterol levels declined with advancing
age, and patients with a history of angina and those who presented with an
anterior MI were significantly less likely to have a cholesterol test ordered.
In 1995-1997, increasing age was inversely associated with having a cholesterol
test performed.
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Table 2. Factors Associated With Total Serum Cholesterol Level Measurement
During Hospitalization for AMI*
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TRENDS IN THE PRESCRIPTION OF HYPOLIPIDEMIC AGENTS
Overall, 3.3% of patients were prescribed hypolipidemic therapy during
hospitalization for AMI. A significant increase was observed in the use of
hypolipidemic therapy in hospitalized patients between 1986 (0.4%) and 1997
(10.7%) (P<.001).
Among patients in whom total serum cholesterol level was measured, hypolipidemic
drug therapy was initiated during hospitalization for AMI and/or at discharge
in a minority of patients (Figure 2). Patients with total cholesterol levels measured in 1997 had a 4-fold increased
likelihood of receiving hypolipidemic therapy compared with patients who did
not have their lipid levels measured in the most recent period under study.
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Figure 2. Trends in prescribing hypolipidemic
therapy according to whether cholesterol level measurements were obtained
during hospitalization for acute myocardial infarction in the Worcester, Mass,
Heart Attack Study.
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Overall, hypolipidemic therapy was initiated during hospitalization
and/or at the time of hospital discharge in 8.0% of patients with a total
cholesterol level of at least 6.2 mmol/L (240 mg/dL). In 1986, 1.9% of
patients with an elevated serum cholesterol level received hypolipidemic therapy,
compared with 36.6% in 1997. In a subgroup analysis of individuals reported
to be receiving hypolipidemic medication before the index hospitalization,
slightly less than three quarters (72.7%) of these patients were discharged
receiving hypolipidemic therapy.
COMMENT
The results of this population-based study of residents from a geographically
defined, representative northeast metropolitan area show a significant decline
in the measurement of total serum cholesterol levels in patients hospitalized
for AMI between 1986 and 1997. After simultaneously controlling for a number
of characteristics, patient age, in particular, emerged as a significant factor
influencing whether a serum cholesterol level test was ordered during hospitalization
for AMI; with advancing age, patients were much less likely to have their
cholesterol levels checked. This trend remained prominent even in the most
recently hospitalized cohort. In contrast to declines in the measurement of
serum cholesterol level over time, there was a significant increase in the
initiation of hypolipidemic therapy during hospitalization for AMI, although
the absolute rate of use remained low even in the mid to late 1990s.
MEASUREMENT OF SERUM CHOLESTEROL LEVELS DURING HOSPITALIZATION FOR
AMI
The importance of the identification and appropriate treatment of hypercholesterolemia
in patients with coronary artery disease through lifestyle interventions and/or
pharmacological approaches is undisputed.23
Several large, well-designed, randomized controlled clinical trials have demonstrated
significant reductions in subsequent morbidity and/or mortality in patients
with coronary artery disease and hypercholesterolemia who were given hypolipidemic
therapy.6, 8, 24-27
Accordingly, the NCEP ATP II has recommended that a complete blood lipid-level
profile be performed in all patients with established CHD.11
Despite these recommendations and the development and clinical availability
of increasingly effective hypolipidemic agents, there is substantial evidence
to suggest that coronary artery disease and hyperlipidemia remain underdiagnosed
and untreated. Analysis of data from the Behavioral Risk Factor Surveillance
study suggests that fewer than one third of patients who needed treatment
for high blood cholesterol levels were receiving it between 1986 and 1990.28 An analysis of approximately 50 000 adult outpatients
with a diagnosis of coronary artery disease revealed that only 25% of patients
had reached the NCEP target level for lipid values.29
Our study is one of the first to report on the use (or nonuse) of cholesterol
level measurements in patients hospitalized for AMI. An argument could be
made that secondary prevention efforts to reduce the occurrence of subsequent
coronary events in these high-risk patients should begin with the index hospitalization.
The initial hospital period represents an important opportunity to diagnose
and initiate therapy for important cardiac risk and prognostic factors, including
an elevated serum cholesterol level. Delays in diagnosis and/or treatment
of hyperlipidemia until after hospital discharge may result in underuse of
hypolipidemic therapy for a variety of reasons, ie, diminished resources in
the outpatient setting, communication breakdowns between cardiologists and
generalists, patient perception of lipid level management as a less important
issue, and patients being lost to follow-up. Evidence suggests that the inpatient
initiation of certain lifestyle interventions and medical therapies results
in better long-term compliance and more lasting rates of success. Smoking
cessation incentives initiated in the hospital setting have been shown to
be more effective than those postponed until outpatient follow-up.30 Rates of use of angiotensin-converting enzyme inhibitors
in a population with heart failure were improved by an inpatient disease management
program compared with conventional methods.31
Accordingly, the immediate assessment of total cholesterol levels in patients
with AMI on admission to the hospital and early initiation of and discussions
about the benefits of a low-fat diet and hypolipidemic therapy, if needed,
are encouraged by the American Heart Association Task Force on Risk Reduction.19 Despite this background, our study documents significant
declines in the measurement of serum cholesterol levels during hospitalization
for AMI during the past decade, with particularly low screening rates in the
mid to late 1990s.
The reasons for the declining use of this simple screening tool are
unclear. Confusion about the appropriate timing of this assay after AMI and
questions about the validity of this measure as a reflection of usual levels
may be playing a role in the underuse of this test. Other possible explanations
may be related to the current health care environment, ie, busy physicians,
capitated care, and decreased lengths of stay. Unfortunately, these variables
could not be assessed adequately in the present study. With the purpose of
getting cardiologists interested in lipid-level management, particularly in
high-risk cardiac patients, and engaging patients at windows of opportunity
such as hospitalization for AMI, Roberts32
examined the reasons why cardiologists might have limited interest in cholesterol
management. Confusion about rapidly changing recommendations from lipid experts,
inadequate knowledge about nutrition and implementation of appropriate dietary
changes, perception of hypolipidemic agents as expensive and fraught with
adverse effects, and lack of financial compensation for time spent in this
endeavor were major reasons cited for physicians' lack of attention to cholesterol
level management.
We suspect that confusion about the validity of cholesterol level measurements
ascertained within the first few hours after AMI may play a role in the observed
trends of decreasing testing of serum cholesterol levels. Data from the Framingham
Heart Study suggest that cholesterol level measurements in the first 24 hours
after AMI are valid, reflect baseline values, and can be used for the institution
of dietary or therapeutic intervention programs.33
On the other hand, data from limited studies have suggested that lipid values
fall significantly after the first few days of hospitalization and can take
up to several weeks to months to return to baseline.34
However, there are several problems with a "wait-and-see" approach to the
measurement of serum cholesterol levels after AMI. As previously noted, the
index hospitalization represents an opportune time to initiate secondary prevention
efforts. Delays in diagnosis and treatment may result in significant undertreatment
of an important and modifiable risk factor for CHD.
One could argue that in the setting of an AMI, physicians have too many
issues to deal with in the first few days of hospitalization to consider the
institution of proper management of lipid levels. Ironically, data from our
study suggest otherwise. Physicians were not only checking serum lipid levels
more often in the past, but they were also more likely to check them in the
first 24 hours after AMI, when these measurements may be more likely to reflect
basal levels.
The outpatient approach to lipid level measurement after AMI also presupposes
that a high number of lipid-level profiles will be falsely low and result
in patients and physicians being falsely reassured or necessitating the cost
of an additional test at 6 to 8 weeks after hospitalization for AMI. In fact,
it has been shown that in patients hospitalized for AMI, most have baseline
LDL levels of greater than 2.6 mmol/L (>100 mg/dL) and/or fail to achieve
LDL levels of less than 2.6 mmol/L (<100 mg/dL) after 3 months of lifestyle
changes.35 In the present study, 20% of lipid
level measurements performed after the initial hospital day demonstrated levels
that were elevated at greater than 6.2 mmol/L (>240 mg/dL). Indeed, the NCEP
ATP II recommendations suggest that a preliminary cholesterol level measurement
during the acute phase of MI provides an approximation that, if elevated,
can assist with initial management decisions.11
In addition, the NCEP ATP II in 1997 recommended the immediate assessment
of a lipoprotein-level profile on admission for AMI.12
A more complete serum lipid-level profile, which requires physicians to be
more proactive in their test-ordering practices, was infrequently ordered
in our study in the late 1990s. Although having data available about the profile
of other serum lipoprotein levels may provide additional insights to patients'
risk and need for more targeted therapies, this testing remains underused
in most hospitalized patients with AMI.
AGE AND OTHER FACTORS ASSOCIATED WITH CHOLESTEROL LEVEL MEASUREMENT
Of the demographic characteristics, medical history, and AMI characteristics
included in our regression analyses, age appeared to have the greatest influence
on whether serum cholesterol levels were measured. This was especially true
in the most recent hospitalized cohort (1995-1997) in which patients aged
75 years and older were 65% less likely to have their cholesterol levels checked
than those aged 55 years and younger.
The appropriateness of screening for, and treatment of, hypercholesterolemia
in older patients, including those with underlying coronary disease, has generated
considerable controversy.36-37
However, analyses from 2 of the more recent trials for hypolipidemic agents
suggest that older patients may also benefit from the receipt of hypocholesterolemic
agents.38-39 These and other data
suggest that the relative absence of cholesterol level measurements in elderly
patients hospitalized with AMI in the present study may result in important
failures to diagnose and subsequently modify an easily correctable risk factor
in a high-risk patient population. Underuse of effective cardiac therapies
in elderly patients with AMI has been noted previously in several other reports
from our communitywide registry, including treatment with ß-blockers,
thrombolytic agents, and aspirin.15
Overall, and within each time period, cholesterol levels were more likely
to be measured in men than women and in those without than with a specific
comorbidity. In subsequent regression analyses, however, including age as
a controlling variable, most of these factors were no longer associated with
cholesterol level measurement. A history of diabetes or hypertension was weakly,
albeit inversely, associated with the measurement of serum cholesterol level
in the entire study sample. Patients with a history of some form of cardiovascular
disease and in whom an AMI develops may receive less cholesterol level testing
because they had a prior assessment of their serum lipid levels and may have
previously received drug treatment.
INITIATION OF HYPOLIPIDEMIC THERAPY
Although significant increases in the initiation of hypolipidemic therapy
were noted from 1986 through 1997, a remarkable underuse of this therapy remains,
even in those with clearly elevated cholesterol levels. Much of this underuse
is, no doubt, secondary to failure to check serum cholesterol levels during
the index hospitalization. However, of patients in whom serum lipid levels
were checked and found to be elevated (>6.2 mmol/L [>240 mg/dL]), only 8.0%
started appropriate drug therapy during hospitalization. Although there was
a marked improvement during the course of our study in the prescribing of
hypolipidemic agents in patients with hypercholesterolemia, the absolute rate
of initiation of hypolipidemic therapy remained low, peaking at 36.6% in 1997.
The extent of use of low-fat and/or other special diets in these patients
is unknown. A perplexing finding was the observation that slightly less than
three quarters of patients who reportedly received hypolipidemic therapy before
the index hospitalization were discharged receiving these medications. This
may be due to poor or inaccurate patient reports of medication use, inadequate
documentation of discharge medications, or physician reluctance to continue
therapy with these agents for varying reasons.
The reasons for the underuse of hypolipidemic therapy, even in patients
with documented undesirable serum cholesterol levels, are unclear. The previously
cited findings of Roberts32 may partially explain
physician reluctance to start therapy in these high-risk patients. It is also
possible that physicians, while noting the increased cholesterol levels, prefer
to wait until after hospital discharge for the initiation of drug therapy
and/or discussions about the importance of making dietary changes. Unfortunately,
by delaying therapy, a window of opportunity for the initiation of hypolipidemic
treatment and other possible secondary prevention measures is lost. Increasing
evidence suggests that the presently used agents (eg, statins) exert an important
plaque-stabilizing effect in addition to their ability to lower cholesterol
levels.40 It is possible that the early initiation
of therapy with these highly effective agents may decrease the occurrence
of early recurrent coronary events, especially in patients at high risk (ie,
those with unstable angina and non–ST-segment elevation MI). A reasonable
quality standard might be that screening for dyslipidemia ought to be performed
before hospital discharge in patients who have not undergone screening for
hyperlipidemia in the past year. This recommendation is in part based on the
rationale that an elevated total cholesterol level in the hospital setting
is likely to be even higher in the usual home environment, and that appropriate
follow-up with subsequent testing in the outpatient setting should be documented.
STUDY STRENGTHS AND LIMITATIONS
Although the focus of the present report was on the inpatient measurement
of serum lipid levels and the initiation of hypolipidemic therapy in patients
with AMI, a limitation of this descriptive epidemiological study was our inability
to describe the measurement of serum cholesterol levels and/or institution
of hypolipidemic therapy after discharge from areawide hospitals. It is certainly
possible that physicians increasingly opt to check patients' cholesterol levels
after discharge from the hospital during their initial outpatient encounters
and more systematically develop a dietary and/or medication plan to more favorably
influence their serum lipid- and lipoprotein-level profile. Unfortunately,
some data suggest that community physicians do not treat patients adequately
with hypolipidemic therapy after a diagnosis of coronary disease.41-42 This will require further explanation
and study. We can only comment on the consistently decreasing inpatient measurements
of cholesterol levels during the decade-long study and the missed opportunity
for the initiation of early secondary prevention modalities that this represents.
Furthermore, an outpatient approach to the diagnosis and management of hyperlipidemia
does not explain the low rates of use of hypolipidemic therapy in patients
documented to have hyperlipidemia.
Similarly, a certain proportion of patients may have had cholesterol
levels measured in the preceding year, and repeated testing was therefore
deemed unnecessary. However, as target cholesterol levels differ in patients
with and without coronary artery disease, and given the rapidity at which
serum cholesterol levels can worsen with adverse dietary changes, one could
argue that even subjects with previously acceptable serum cholesterol levels
should undergo retesting after AMI. As with any observational study, there
may have been additional factors that influenced the determination of serum
cholesterol levels as well as initiation of hypolipidemic therapy. Other factors
that may have influenced physicians' test-ordering and treatment practices
include severity of underlying and acute coronary disease, presence of other
comorbidities, sociodemographic status, insurance coverage, and patients'
adherence to lifestyle and/or treatment recommendations. Data were also not
available about the number and characteristics of patients who may have already
had their cholesterol status known, particularly during a recent period before
their AMI, which may have reduced the likelihood of further testing of lipid
levels during their index hospitalization. We were similarly unable to assess
whether physician specialty or practice type played a significant role in
affecting these end points. Although the extent of this situation remains
unknown, a number of patients admitted for AMI likely had undergone previous
screening for hyperlipidemia. There may have been many reasons why these individuals
were not receiving hypolipidemic drugs at the time of hospital admission,
including that the patients were not hyperlipidemic at the time of the screening,
that hyperlipidemia was managed with changes in diet, or that the patients
had been prescribed hypolipidemic drugs but did not take them because of adverse
effects, costs, or other reasons. Finally, we did not compare the long-term
outcomes among those who did, compared with those who did not, undergo measurement
of cholesterol levels. Although these data are available, the nonrandomized
nature of this study precludes any meaningful conclusions being derived about
the effects (or lack thereof) of current test-ordering practices, given the
influence of a variety of potentially confounding factors, only some of which
were measured.
The strengths of this study include its ability to reflect accurately
hospital cholesterol level measurement practices in a large number of patients
with AMI from a predefined geographic area during a prolonged period. We believe
that this is the first report presenting data concerning trends in the early
assessment and management of cholesterol levels in patients with AMI from
the perspective of a multihospital, population-based study. Moreover, the
socioeconomic and demographic characteristics of residents of the Worcester
metropolitan area have been shown to be similar to those of the rest of the
United States, enhancing the potential generalizability of our study findings.
CONCLUSIONS
This study reports a decreasing use of cholesterol level measurement
in patients hospitalized for AMI. In addition, an increasing proportion of
these tests are being performed at a later time during the index hospitalization
than has been shown to be valid, which increases the likelihood of artificially
low test results. Although the initiation of hypolipidemic therapy is occurring
in increasing proportions of patients with AMI who have documented hyperlipidemia,
it still occurs in a minority of eligible subjects. Our analyses suggest that
the most important factor negatively influencing test-ordering practices is
advancing age. The present results suggest that substantial room remains for
improvement in the diagnosis and management of hyperlipidemia in all patients
with AMI with the goal of reducing subsequent morbidity and mortality in these
patients.
AUTHOR INFORMATION
Accepted for publication October 3, 2000.
Supported by grant RO1 HL35434 from the National Heart, Lung, and Blood
Institute, Bethesda, Md.
Corresponding author and reprints: Jorge Yarzebski, MD, MPH, Division
of Cardiovascular Medicine, University of Massachusetts Medical School, 55
Lake Ave N, Worcester, MA 01655 (e-mail: jorge.yarzebski{at}umassmed.edu).
From the Division of Cardiovascular Medicine, Department of Medicine,
University of Massachusetts Medical School, Worcester.
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