|
| HOME | SUBSCRIPTIONS | CURRENT ISSUE | PAST ISSUES | CARDIOSOURCE | SEARCH | HELP | FEEDBACK |
|
|
|
|||||||||
|
|||||||||||
|
J Am Coll Cardiol, 2002; 39:60-69 © 2002 by the American College of Cardiology Foundation |
* Departments of Basic Science and Internal Medicine, Cardiology Section, University of Missouri-Kansas City School of Medicine, Truman Medical Center, Kansas City, Missouri, USA
Albany Medical College, Albany, New York, USA
University of Missouri-Kansas City School of Medicine, Mid-America Heart Institute, Kansas City, Missouri, USA
Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan, USA
|| Henry Ford Heart and Vascular Institute, Detroit, Michigan, USA
Manuscript received December 8, 2000; revised manuscript received September 17, 2001, accepted September 20, 2001.
* Reprint requests and correspondence: Dr. Peter A. McCullough, Department of Internal Medicine, Cardiology Section, University of Missouri-Kansas City School of Medicine, Truman Medical Center, 2301 Holmes Street, Kansas City, Missouri 64108, USA.
mcculloughp{at}umkc.edu
 |
Abstract |
|---|
 Top Abstract MethodsResultsDiscussionReferences |
|---|
BACKGROUND: Previous epidemiologic studies suggest that the increasing prevalence of heart failure is a consequence of improved survival coupled with minimal changes in disease prevention. Developing new, efficient methods of assessing the incidence and prevalence of heart failure could allow continued surveillance of these rates during an era of rapidly changing treatments and health care delivery patterns.
METHODS: Using administrative data sets, we created a definition of heart failure using diagnosis codes. After adjustment for patients leaving our health system or death, we derived the incidence, prevalence and mortality of the population with heart failure from 1989 to 1999.
RESULTS: A total of 29,686 patients of all ages, 52.6% women and 47.4% men, met the definition of heart failure. Mean ages were 71.1 ± 14.5 for women and 67.7 ± 14.4 for men, p < 0.0001. Race proportions were 50.5% white, 44.6% African American and 4.9% other race. Incidence rates were higher in men and African Americans across all age groups. There was an annual increase in prevalence of 1/1,000 for women and 0.9/1,000 for men, p = 0.001 for both trends.
CONCLUSIONS: Through the feasible and valid use of automated data, we have confirmed a chronic disease epidemic of heart failure manifested primarily by an increase in prevalence over the past decade. Our surveillance system mirrors the results of epidemiologic studies and may be a valid method for monitoring the impact of prevention and treatment programs.
| ||||||||||||||||||||
|
Methods |
|---|
|
TopAbstractMethodsResultsDiscussionReferences |
|---|
Case definitions.
An index case of CHF was defined as an aligned patient who had accumulated at least two outpatient encounters (emergency department, urgent care or clinic) or one hospitalization coded for CHF. The 9th International Classification of Diseases, Clinical Modification (ICD-9-CM) codes for CHF used were previously validated in CHF case findings and included the following: 428.XX, 398.91, 402.01, 402.11, 402.91, 404.00, 404.01, 404.03, 404.10, 404.11, 404.13, 404.90, 404.91, 404.93 (12,13). Of note, the codes 404.00, 404.10 and 404.90 were included to capture patients with combined heart and renal failure. Hospitalizations for CHF required diagnosis-related group (DRG) 127 or one of the above ICD-9-CM codes in the principal position. In addition, patients with 
1 hospital discharge coded with DRG 124 and one of the ICD-9-CM codes in the preceding text in the principal diagnosis position were included. This included patients whose principal diagnosis was CHF but, because of a diagnostic catheterization during the stay were assigned to DRG 124 instead of 127. This search strategy excluded those patients whose only code for CHF was in the secondary position. For hospital admissions, DRG codes were assigned by professional coders and approved by the attending physician. During outpatient visits, the attending physician assigned the codes at the time of the encounter. Death was ascertained by death within an HFHS facility, death confirmed by State of Michigan Death Registry tapes or the National Center for Health Statistics Death Index. We observed a >99% vital status ascertainment after five or more years from an index year. Each patient had a unique medical record number that avoided double counting.
Data management. We applied the index case search definition to all aligned HFHS patients and all HAP patients beginning in the calendar year 1989. Among cases found in 1989, it was assumed that the ratio of index to prevalent cases was 1 to 1. For each subsequent year, index cases were queried for the presence or absence of any medical care delivered. If no activity was found, a search for death records from the three sources listed above was done. If death was not found, individuals were considered to be temporarily out of HFHS or HAP and were kept in a dataset for continued prospective resource utilization or death. If in a subsequent year, a patient was found to be active or dead, the prior year prevalence pool was amended to reflect the presence of that individual, thus accounting for patients who exited the HFHS. Patients with established CHF who entered the system were counted as index cases once the ICD-9-CM definition was met. Patients without CHF entering the system were counted in the denominator of HFHS patients for that year. Once declared an index case, CHF was considered irreversible and present until death. This methodology was unable to detect and confirm reversible cases of CHF including myocarditis, metabolic cardiomyopathies and cases where revascularization improved cardiac function to a degree where CHF could be considered cured. It was expected that these cases were sufficiently uncommon as to affect the main results.
Data validation.
To check on the positive predictive value of the index case definition by ICD-9-CM coding, a case validation procedure was carried out. A 1% random sample, n = 271 (58.3% women, 41.7% men) of REACH subjects was taken, and chart abstraction was performed with explicit criteria applied by the Framingham and NHANES I definitions of CHF (7,10). A total of 172 (63.5%) subjects met the Framingham definition, and 151 (55.7%) subjects met the NHANES definition (score 3) of CHF. Of those who met any definition of CHF (n = 200, 73.8%), the mean ejection fraction was 42.5 ± 16.0%. Because both the Framingham and NHANES I definitions were designed for populations free of disease and not for active HFHS patients, a second validation procedure was carried out. Two physicians, one internist and one cardiologist, were given a portion of the sample comprised of patients under their care and performed chart abstraction for confirmation of CHF by chart notes, with classification according to the New York Heart Association (NYHA). Of the sample reviewed (n = 263, 44.1% women, 55.9% men), 82.9% of cases were confirmed to have CHF. Of those with validated CHF at the time of last clinical encounter, the proportions of NYHA classes were as follows: class I, 25.1%; class II, 36.1%; class III, 28.9% and class IV, 9.9%. Of those without CHF mentioned in the chart notes: 60.0% had dyspnea listed, and 85.0% had a primary cardiac diagnosis such as coronary artery disease, atrial fibrillation, prior cardiac surgery or structural heart disease. That is, while not having CHF explicitly listed in the chart, these patients received ICD-9-CM codes and had the cardiac substrate and associated findings to support the presence of CHF. Only 5.0% had no mention of cardiovascular disease in the chart notes. Most likely, this overestimation was counterbalanced by the previously described community underestimation of CHF by hospitalization ICD-9-CM codes described in the Corpus Christi Heart Project (14). Thus, investigators felt that the study definitions and population characteristics would yield valid point estimates on the epidemiology of CHF, and statistical analysis of the entire population was undertaken.
Statistical analysis. Univariate statistics were reported as proportions or means, and comparisons were made with chi-square or analysis of variance, as appropriate. Incidence and prevalence were reported in terms of total number of HFHS patients for that given year. This adjusted for denominator change, which was small given the stability of the HFHS during the study period. Incident cases excluded those who had been identified in prior years. Prevalent cases included: 1) those identified in prior years who were active in the HFHS and alive, and 2) those who were inactive in that year but found to be dead or alive in future years. This prevented the problem of migrating patients changing either the numerator or denominator. Age- and gender-adjustment of rates was carried out using direct standardization to the 1994 (midpoint) age and gender structure of the HFHS population (Table 1). Cox regression was used to compare adjusted survival among groups of interest. Statistical significance was chosen at the alpha <0.05 level.
|
|
Results |
|---|
|
TopAbstractMethodsResultsDiscussionReferences |
|---|
|
|
|
|
|
|
|
|
|
|
Discussion |
|---|
|
TopAbstractMethodsResultsDiscussionReferences |
|---|
Incidence.
Our incidence rates were consistent with the few epidemiologic sources of data on incidence through the 1990s (9,15,16). Framingham results during the 1980s reported an incidence of CHF among persons age 45 years of 4.7 cases/1,000 in women and 7.2 cases/1,000 in men (9). This is in contrast with REACH, where the denominator was HFHS patients of all ages and the annual incidence was 5.3/1,000 in women and 5.5/1,000 in men. Our finding of a male predominance in incidence confirms findings published from Framingham and other studies (9,17). However, there may be an underrepresentation of the problem of heart failure in men (5). Previous studies of asymptomatic left ventricular dysfunction have found men are twice as likely as women to have asymptomatic disease. In addition, CHF is more common in men when a clinical examination or echocardiography has been used to define the condition (2). Therefore, women may have been more likely to manifest symptomatic CHF and, hence, be captured by the REACH methodology, which requires ICD-9-CM codes generated by face-to-face physician encounters or hospitalizations. The dominance of African Americans in incidence rates among HFHS patients confirmed earlier risk estimates from smaller studies (5). As previously shown, in general African Americans have a 50% to 75% excess rate of new heart failure as non-African Americans.
Prevalence. Our prevalence rates were consistent with prior cross-sectional studies, which suggested a rise in the prevalence of CHF in the U.S. when assessed at different time periods (NHANES I 1971 to 1974, NHANES II 1976 to 1980) (6,7). These time periods, however, almost certainly do not reflect the widespread use of vasodilators and beta-blockers, which have been shown to reduce CHF mortality. Hence, our finding of a sharp rise in prevalence through the 1990s represents new information pointing to a larger chronic disease epidemic on the basis of prevalence than has been previously described. We acknowledge that our methods report "prevalence" in the early years of data acquisition including 1989 as a starting point and up to approximately 1995 as a representation of cumulative incidence. It is only after all existing cases have been captured using ICD-9-CM codes that true prevalence can be appreciated. The reported, annualized point prevalence of CHF in REACH was 10.5/1,000 in women and 10.9/1,000 in men. This is considerably greater than the age-adjusted point prevalence of CHF reported from Framingham during the 1980s (7.7/1,000 in women and 7.4/1,000 in men) (9). Our findings suggest that the more comprehensive ICD-9-CM search algorithm and use of inpatient and outpatient encounters in REACH have overcome the underreporting of CHF prevalence in communities by the use of hospitalization discharge codes alone (14). In addition, prevalence estimates from Framingham represent a denominator of adults >45 years, unlike REACH, which used a denominator of HFHS patients of all ages (Table 3). Patients <45 years (n = 2,006 [6.8%]) were retained for two reasons: 1) to allow representation of younger individuals with CHF not included in prior epidemiologic studies, and 2) to provide a database for case finding of young patients with CHF in the HFHS for future studies. When compared with multiple large-scale epidemiologic studies of prevalence through the 1990s however, the prevalence found in our study is in line with the 9.0/1,000 to 15.0/1,000 rates reported (2,5,14,18,19).
|
Study limitations.
We acknowledge that there are multiple limitations to our study. Using ICD-9-CM codes as the basis for a definition of CHF does not equate to the stringent criteria used in Framingham, NHANES or the opinion of clinicians as demonstrated and discussed in our data validation section. Hence, our study is hampered by misclassification bias. This bias is almost certainly nondifferential and would bias any analytic conclusion to the null hypothesis. For example, a null hypothesis could be that prevalence is not changed over time. Our methods indicate that any bias towards this null makes the case for a rise in prevalence even stronger. It is possible that prevalent cases were counted as incident cases if there was a prolonged period (several years) without encounters coded for CHF prior to 1989; however, this incidence-prevalence bias is unlikely to affect point estimates in later years given the reported survival duration in our study. It was also possible that a differential exit of CHF or healthy patients from the system who remain alive could shift the denominator and change both incidence and prevalence rates. Another source of bias would be a secular trend over time for the HFHS to take in patients with greater comorbidities or recruit more patients with CHF. The HFHS started a cardiac transplant service in 1985 and maintained it throughout the study period with no change in numbers of heart failure specialists and no change in the approximately 15 annual transplants performed. Furthermore, we are unaware in any shift in case-mix within the HFHS and acknowledge this is an area worthy of future study. Our study did not have the resources to evaluate full decision statistics including the negative predictive value of the ICD-9-CM code algorithm. An example evaluation would call for a random chart review of 5,000 HFHS charts to yield an expected 100 patients with and 4,900 without CHF, respectively (assuming a point prevalence of 
2%). Random sample sizes smaller than 5,000 would likely inflate the negative predictive value because of the low point prevalence of CHF in the HFHS population. Extrapolation of our results may be limited by the relatively high (20.9%) managed care component of the study sample. Conversely, having a mixed population of fee-for-service, managed care, Medicaid and underinsured patients is the strength of REACH not seen in other epidemiologic studies. Generalizability to the U.S. or Western European countries is limited due to the high proportion of African Americans in our sample. Conversely, REACH represents the largest cohort of African Americans with CHF in the medical literature today, which adds to the observations taken from small numbers of African Americans in cross-sectional and cohort studies (5,13,15,23).
Study implications. The REACH study adds to current insights into the epidemiology of CHF in the following ways: 1) it demonstrated a feasible, automated, "turn-key" methodology that may be replicated by other health systems; 2) it included information on CHF across all age ranges and was not restricted to those >65 years (e.g., studies from Medicare data); 3) it comprised CHF cases identified on an in-patient and outpatient basis and, hence, was more useful in describing the global aspects of the problem than studies of hospitalized patients only; 4) it included a large proportion of African Americans not previously captured in U.S. or European epidemiologic studies or randomized trials; and 5) although this will require validation, REACH presumably included patients with both systolic and diastolic dysfunction forms of CHF and, hence, is expected to be a more complete description of the full spectrum of CHF outcomes than those from randomized trials of left ventricular dysfunction alone (2,24–27).
Conclusions. We conclude that, by use of ICD-9-CM codes and automated sources of data, the epidemiology of CHF can be described within health systems. Through the 1990s, there has been a growing epidemic of CHF prevalence captured by ICD-9-CM codes. Aging of the U.S. population almost certainly is the most important factor in this evolving epidemic. Consistent with studies from earlier decades, men have higher incidence rates but poorer survival. Women now predominate the CHF prevalence pool and appear to present with CHF at older ages. The CHF epidemic extends to African Americans, who have significantly higher rates of new onset CHF and suffer a poorer long-term survival compared with whites. The techniques of identifying incident and prevalent cases in REACH may provide an important tool for cost-effectively evaluating the impact of new treatments on large populations of patients.
|
Acknowledgments |
|---|
|
Footnotes |
|---|
|
References |
|---|
|
TopAbstractMethodsResultsDiscussionReferences |
|---|
70 years of age with congestive heart failure and normal versus abnormal left ventricular ejection fraction. Am J Cardiol. 1997;79:216–219[CrossRef][Medline]
This article has been cited by other articles:
|
|
 |
|
  R. Antonicelli, P. Testarmata, L. Spazzafumo, C. Gagliardi, G. Bilo, M. Valentini, F. Olivieri, and G. Parati Impact of telemonitoring at home on the management of elderly patients with congestive heart failure J Telemed Telecare, September 1, 2008; 14(6): 300 - 305. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. J. Chicco, G. C. Sparagna, S. A. McCune, C. A. Johnson, R. C. Murphy, D. A. Bolden, M. L. Rees, R. T. Gardner, and R. L. Moore Linoleate-Rich High-Fat Diet Decreases Mortality in Hypertensive Heart Failure Rats Compared With Lard and Low-Fat Diets Hypertension, September 1, 2008; 52(3): 549 - 555. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. J. Goldberger, M. E. Cain, S. H. Hohnloser, A. H. Kadish, B. P. Knight, M. S. Lauer, B. J. Maron, R. L. Page, R. S. Passman, D. Siscovick, et al. American Heart Association/American College of Cardiology Foundation/Heart Rhythm Society Scientific Statement on Noninvasive Risk Stratification Techniques for Identifying Patients at Risk for Sudden Cardiac Death: A Scientific Statement From the American Heart Association Council on Clinical Cardiology Committee on Electrocardiography and Arrhythmias and Council on Epidemiology and Prevention J. Am. Coll. Cardiol., August 25, 2008; (2008) j.jacc.2008.05.003v1. [Full Text] [PDF]
|
|
|
|
 |
|
 M. C. Pinder, Z. Duan, J. S. Goodwin, G. N. Hortobagyi, and S. H. Giordano Congestive Heart Failure in Older Women Treated With Adjuvant Anthracycline Chemotherapy for Breast Cancer J. Clin. Oncol., September 1, 2007; 25(25): 3808 - 3815. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. Jourdain, G. Jondeau, F. Funck, P. Gueffet, A. Le Helloco, E. Donal, J. F. Aupetit, M. C. Aumont, M. Galinier, J. C. Eicher, et al. Plasma Brain Natriuretic Peptide-Guided Therapy to Improve Outcome in Heart Failure: The STARS-BNP Multicenter Study J. Am. Coll. Cardiol., April 24, 2007; 49(16): 1733 - 1739. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Lindenfeld and F. A. Masoudi Fluid Retention With Thiazolidinediones: Does the Mechanism Influence the Outcome? J. Am. Coll. Cardiol., April 24, 2007; 49(16): 1705 - 1707. [Full Text] [PDF]
|
|
|
|
 |
|
 L. A. Allen and C. M. O'Connor Management of acute decompensated heart failure Can. Med. Assoc. J., March 13, 2007; 176(6): 797 - 805. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. Aspromonte, V. Ceci, A. Chiera, C. Coletta, A. D'Eri, M. Feola, P. Giovinazzo, L. Milani, F. Noventa, A. B. Scardovi, et al. Rapid Brain Natriuretic Peptide Test and Doppler Echocardiography for Early Diagnosis of Mild Heart Failure Clin. Chem., September 1, 2006; 52(9): 1802 - 1808. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. A. H. Cann Hypothesis: dietary iodine intake in the etiology of cardiovascular disease. J. Am. Coll. Nutr., February 1, 2006; 25(1): 1 - 11. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. F.L. Schinkel, D. Poldermans, V. Rizzello, R. T. van Domburg, R. Valkema, A. Elhendy, E. Biagini, E. P. Krenning, M. L. Simoons, and J. J. Bax Impact of Diabetes Mellitus on Prediction of Clinical Outcome After Coronary Revascularization by 18F-FDG SPECT in Patients with Ischemic Left Ventricular Dysfunction J. Nucl. Med., January 1, 2006; 47(1): 68 - 73. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. S. Wang, J. M. FitzGerald, M. Schulzer, E. Mak, and N. T. Ayas Does This Dyspneic Patient in the Emergency Department Have Congestive Heart Failure? JAMA, October 19, 2005; 294(15): 1944 - 1956. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. J. Gallagher, B. A. Franklin, J. K. Ehrman, S. J. Keteyian, C. A. Brawner, A. T. deJong, and P. A. McCullough Comparative Impact of Morbid Obesity vs Heart Failure on Cardiorespiratory Fitness Chest, June 1, 2005; 127(6): 2197 - 2203. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. A. Wellenius, T. F. Bateson, M. A. Mittleman, and J. Schwartz Particulate Air Pollution and the Rate of Hospitalization for Congestive Heart Failure among Medicare Beneficiaries in Pittsburgh, Pennsylvania Am. J. Epidemiol., June 1, 2005; 161(11): 1030 - 1036. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Endorsed by the European Society of Intensive Care, Authors/Task Force Members, M. S. Nieminen, M. Bohm, M. R. Cowie, H. Drexler, G. S. Filippatos, G. Jondeau, Y. Hasin, J. Lopez-Sendon, et al. Executive summary of the guidelines on the diagnosis and treatment of acute heart failure: The Task Force on Acute Heart Failure of the European Society of Cardiology Eur. Heart J., February 2, 2005; 26(4): 384 - 416. [Full Text] [PDF]
|
|
|
|
|
|
G. Zuccala, G. Onder, E. Marzetti, M. R. L. Monaco, M. Cesari, A. Cocchi, P. Carbonin, R. Bernabei, and for the GIFA Study Group Use of angiotensin-converting enzyme inhibitors and variations in cognitive performance among patients with heart failure Eur. Heart J., February 1, 2005; 26(3): 226 - 233. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. Roman-Sanchez, P. Conthe, J. Garcia-Alegria, J. Forteza-Rey, M. Montero, C. Montoto, and for the Heart Failure Working Group of the Spanish Factors influencing medical treatment of heart failure patients in Spanish internal medicine departments: a national survey QJM, February 1, 2005; 98(2): 127 - 138. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. G. Bongartz, M. J. Cramer, P. A. Doevendans, J. A. Joles, and B. Braam The severe cardiorenal syndrome: 'Guyton revisited' Eur. Heart J., January 1, 2005; 26(1): 11 - 17. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. McCord, B. J. Mundy, M. P. Hudson, A. S. Maisel, J. E. Hollander, W. T. Abraham, P. G. Steg, T. Omland, C. W. Knudsen, K. R. Sandberg, et al. Relationship Between Obesity and B-Type Natriuretic Peptide Levels Arch Intern Med, November 8, 2004; 164(20): 2247 - 2252. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Gackowski, R. Isnard, J.-L. Golmard, F. Pousset, A. Carayon, G. Montalescot, J.-S. Hulot, D. Thomas, W. Piwowarska, and M. Komajda Comparison of echocardiography and plasma B-type natriuretic peptide for monitoring the response to treatment in acute heart failure Eur. Heart J., October 2, 2004; 25(20): 1788 - 1796. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. A. Nichols, C. M. Gullion, C. E. Koro, S. A. Ephross, and J. B. Brown The Incidence of Congestive Heart Failure in Type 2 Diabetes: An update Diabetes Care, August 1, 2004; 27(8): 1879 - 1884. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Bundkirchen and R. H.G Schwinger Epidemiology and economic burden of chronic heart failure Eur. Heart J. Suppl., August 1, 2004; 6(suppl_D): D57 - D60. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
V. L. Roger, S. A. Weston, M. M. Redfield, J. P. Hellermann-Homan, J. Killian, B. P. Yawn, and S. J. Jacobsen Trends in Heart Failure Incidence and Survival in a Community-Based Population JAMA, July 21, 2004; 292(3): 344 - 350. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. E. Lanfear, S. Marsh, S. Cresci, W. D. Shannon, J. A. Spertus, and H. L. McLeod Genotypes associated with myocardial infarction risk are more common in African Americans than in European Americans J. Am. Coll. Cardiol., July 7, 2004; 44(1): 165 - 167. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A F L Schinkel, E C Vourvouri, J J Bax, F Boomsma, M Bountioukos, V Rizzello, E Biagini, E Agricola, A Elhendy, J R T C Roelandt, et al. Relation between left ventricular contractile reserve during low dose dobutamine echocardiography and plasma concentrations of natriuretic peptides Heart, March 1, 2004; 90(3): 293 - 296. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Mueller, A. Scholer, K. Laule-Kilian, B. Martina, C. Schindler, P. Buser, M. Pfisterer, and A. P. Perruchoud Use of B-Type Natriuretic Peptide in the Evaluation and Management of Acute Dyspnea N. Engl. J. Med., |
