Insights Into the Contemporary Epidemiology and Outpatient Management of
Congestive Heart Failure

(Jon's note: epidemiology's braod definition is the study of all things that
contribute to the occurrence or non-occurrence of a disease in a certain
population of patients)

	September 10, 1999 - We studied the epidemiology and prognosis in
patients with chronic CHF, who were treated and followed at a specialized
clinic. Consecutive patients were followed up in a CHF clinic between
September 1989 and March 1996.
	Of the 628 patients, 566 were confirmed to have CHF. Average follow-up
was 518 days. Average patient age was 66 and 68% were men. Patients with
preserved systolic function were older, more often female, had higher average
systolic BP, less ischemic heart disease and fewer arrhythmias than those with
systolic dysfunction. Although there a lower EF meant greater risk of
mortality, the survival of those with preserved systolic function wasn't much
different from those with systolic failure.
	Increased mortality was seen with increasing age, class 4 status,
ischemic cause of disease, elevated blood creatinine level, diuretic use, and
systolic dysfunction. Beta-blocker use was associated with reduced risk.
	Our data suggest that a specialized outpatient clinic can improve
treatment of CHF patients. The high mortality risk in CHF with preserved
systolic function shows the need to find effective therapies for this
condition.

Long version:

	CHF currently affects 1-2% of North American adults. They have poor
functional capacity, decreased quality of life, and increased mortality and
complications. Mortality rates higher than 40% within 2 years of diagnosis
are common. CHF patients require frequent hospitalization; 19% of patients in
SOLVD were hospitalized within 1 year of diagnosis, and more than 40% of CHF
patients require readmission within 3-6 months of hospital discharge.
	Although significant advances have been made in CHF therapy, there
has been surprisingly little change in mortality rates over the past 40
years. Although this may be caused by higher proportions of older and sicker
patients, another possibility may be that proven CHF therapies like ACE
inhibitors are not been well used.
	Specialized clinics providing intensive outpatient care for CHF
patients have been established. At the University of Alberta Hospital, a
Heart Function Clinic was established in 1989 to monitor CHF patients, apply
proven therapies, and provide counseling, education, and intensive follow-up.
This study was done to examine our experience in this clinic, and the
management and prognosis of CHF in the 1990s, with attention to comparing
patients with left ventricular systolic dysfunction to those with preserved
left ventricular function.

Study

	Between September 1989 and December 1995, 628 adult patients were
evaluated for CHF at the University of Alberta Hospital Heart Function Clinic.
This clinic is staffed by physicians, nurse practitioners, pharmacists,
dieticians, and social workers. The final study included 566 patients.
Treatment of each patient was by the attending clinic physician and although
ACE inhibitor use was stressed, no protocols were mandatory during the study.
	EF measurements by echo or MUGA were taken from all patients at
baseline. Patients were defined as having CHF caused by systolic dysfunction
if their EF was less than 45%. If patients had an EF greater than 45% or if
their main problem was in ventricular diastolic relaxation, they were said to
have "preserved systolic left ventricular function." CHF causes were ischemia,
high BP, or other, which included idiopathic dilated cardiomyopathy, valve
disease, exposure to cardiotoxic drugs or excess alcohol consumption and no
ischemic cause.
	We collected patient demographics, cause and characteristics of CHF,
functional heart class, presence or absence of other health conditions,
ventricular or atrial arrhythmias, blood pressure, heart rate, results of
lab tests for serum sodium, potassium, creatinine, and hemoglobin levels, and
current meds. These were entered into a database. The study data were
extracted from this database by software according to defined criteria. When
the database was incomplete, original charts were reviewed to get data.

Results

	Average follow-up lasted 518 days. Baseline EF was measured by echo
(49%), MUGA (35%), or cath (15%). Most patients (65%) had moderate to severe
systolic dysfunction with an EF less than 40%, but 22% of patients had EF
greater than 45%. These patients were said to have preserved systolic
function.
	Ischemia and high blood pressure were the most common causes for CHF.
Idiopathic cardiomyopathy (13%), valve disease (7%), and alcoholic
cardiomyopathy (2%) were less common. Compared to those with systolic
dysfunction, patients with preserved systolic function were older at
diagnosis, more often female and had more history of high BP, but fewer had
ischemic heart disease as primary cause of CHF. No patients had hypertrophic
or restrictive cardiomyopathy. Patients with preserved systolic function had
a lower incidence of ventricular arrhythmia and kidney dysfunction.
	Patients with preserved systolic function were treated less often with
ACE inhibitors, diuretics, aspirin, and amiodarone; and were treated more
often with beta-blockers and calcium channel blockers. 83% of patients got
ACE inhibitors. The most commonly prescribed ones were enalapril
(10mg/day average), lisinopril (10mg/day average), and captopril
(62mg/day average). Of patients taking digoxin, only 44% had atrial
arrhythmia; 42% had preserved systolic function and 58% had systolic
dysfunction. 61% of the 44 patients with preserved systolic function and 57%
of the 122 patients with systolic dysfunction took Coumadin.
	During follow-up, 148 of the 566 patients died, 122 (82%) from
cardiac causes and 26 (18%) from noncardiac causes. Analysis showed 1-year
survival rates of 95% for class one patients, 93% for class 2, 83% for class
3, and 70% for class 4 patients. At 2 years, the survival rates were 87% for
class one, 83% for class 2, 69% for class 3, and 52% for class 4. At 3 years,
they were 84%, 77%, 60%, and 34%, respectively. Although there was a negative
trend in survival as EF decreased, survival in patients with systolic
dysfunction vs preserved systolic function were not much different. Although
patients with an ischemic cause had an increased mortality risk compared to
those with a nonischemic cause, the difference wsa not significant.
	The following factors at diagnosis were associated with increased
mortality risk: age older than 70 years, functional class, elevated serum
creatinine (greater than 130 µmol/L), and ischemic cause of CHF.
	Regarding meds, beta-blockers were associated with reduced mortality.
Metolazone, thiazides and loop diuretics were associated with increased
mortality risk. ACE inhibitors gave a trend toward reduced risk. In the 121
patients with preserved systolic function, only age was associated with higher
mortality risk.

Discussion

	We found that a specialized outpatient CHF clinic can optimize use of
proven therapy. That 83% of patients got ACE inhibitors is a huge improvement
from the 32-54% reported in recent practice audits. Our survival data compare
favorably to data from other CHF clinics and clinical trials. This suggests
that effectively applying proven therapies reduces mortality.
	An unsettled issue is the best dose of ACE inhibitors. Patients in
this study took lower doses of ACE inhibitors than were used in the major CHF
trials. Although higher doses appear more beneficial, patients attending CHF
clinics are often frail, with low BP, and cannot tolerate higher doses of ACE
inhibitors.
	CHF patients whose left ventricular systolic function may be normal
or who have diastolic dysfunction form a distinct subgroup of patients. The
proportion of patients with preserved systolic function in our study (22%) is
lower than that reported in previous studies of hospitalized patients but is
consistent with published reports of outpatients with chronic CHF. Although
they tended to be older, have more history of high BP, and with a higher
proportion of women, there were no factors on physical exam that accurately
identified which had preserved systolic function or systolic dysfunction.
This emphasizes the need for measurement of LVEF in CHF patients.
	The mortality rates in our patients with preserved systolic function
did not differ from those seen in patients with systolic dysfunction,
regardless of the presence or absence of ischemic heart disease. Although
this could be chance or some other factor, our data suggest that the mortality
risk from diastolic dysfunction or CHF with preserved systolic function can
be substantially worse than previously thought.
	Advancing age, poor functional capacity, reduced LVEF, ischemic cause,
and elevated serum creatinine level have all been shown in previous studies
to predict mortality in CHF. Our study found that low serum sodium,
ventricular arrhythmias, and diabetes were not negative prognostic factors in
CHF.

Limitations

	The major limitation of our study is the likelihood of selection bias
in the patient population. Although our study sample is a consecutive series
of patients referred to the CHF clinic, it is not a random sample of people
with CHF. However, since all CHF cases were confirmed using standard criteria
and objective EF testing, our study does give useful information.

Conclusion

	Despite the advances made in the past 20 years in CHF therapies,
challenges remain. The foremost is translating these therapies into effective
practice. Our data support that a specialized outpatient CHF clinic can
improve practice patterns, as shown by the high rate of ACE inhibitor use
and outcomes in CHF patients. The demonstration of high mortality risk in
patients with preserved systolic left ventricular function emphasizes the
need for effective therapies for this condition.

Am Heart J 138(1):87-94, 1999