Trends in incidence and prognosis of heart failure

You always pass failure on the way to success

Mark T. Kearneya and Michael Marberb,*

a Department of Cardiology GKT School of Medicine London, King's College Hospital London UK
b St Thomas's Hospital, London, UK

* Correspondence to: Michael Marber, Department of Cardiology, King's College London, The Rayne Institute, St Thomas's Hospital, London SE1 7EH, UK. Tel +44 20 9228191; fax +4420 9605659
E-mail address: mike.marber{at}kcl.ac.uk

Received 9 September 2003; accepted 25 September 2003

This editorial refers to ''Decreasing one-year mortality and hospitalization rates for heart failure in Sweden by M. Schaufelberger et al. on page 300{dagger}

The last two decades of the 20th century saw a significant improvement in our understanding of the aetiology and pathophysiology of chronic heart failure (CHF), a disorder with a mortality rate higher than many soft tissue tumours.1Multiple neurohumoral pathways, abnormalities of cardiac shape, size and electrical activation, have been shown to influence the natural history of CHF. Based on this understanding, randomized controlled trials established angiotensin converting enzyme inhibitors, and more recently beta-adrenoceptor blockers and spironolactone, as agents that can improve the morbidity and mortality of CHF. On the way, we have also discovered those drugs that are best avoided.

As a new era of device therapy for treating patients with CHF emerges it is timely to step back and assess what progress has been made using pharmacological agents, in the ‘real world’, outside the setting of randomized controlled trials. To this end the report in this issue of The European Heart Journal from Schaufelberger et al.2is relevant in that it provides information on all patients admitted to hospitals in Sweden with a diagnosis of heart failure during the last 12 years of the 20th century. This paper adds to, and reinforces similar data recently published by McMurray's group in Glasgow, which reported mortality and hospitalisation rates in 66 547 patients admitted with heart failure in Scotland between 1986 and 1995.3,4

1. Do population studies suggest that we are successfully altering the natural history of chronic heart failure?

Schaufelberger et al. report complete data on all admissions to hospitals in Sweden in patients aged 45–84 years between 1988 and 2000 with a principal or secondary diagnosis of heart failure based on International Classification of Disease Coding. They describe the temporal pattern of hospital admissions and 30 day and 1-year mortality using data from over 156 000 patients.

The authors demonstrate clearly that since 1993, when hospitalizations for heart failure reached a peak of 317 men and 244 women per 100 000 head of population, admission rates have declined significantly; to 237 and 171 per 100 000 in 2000. Less than 10% of admissions in both men and women were in patients aged less than 64 years, confirming that CHF is predominantly a disease of the elderly. Moreover, during these years 30-day and annual mortality declined in men and women of all ages. These changes were independent of age decile, gender or whether heart failure was a principal or secondary ICD code. The similar study by MacIntyre et al.3examined 66 547 consecutive patients with first admission for heart failure in Scotland. The Scottish study is consistent with that of Schaufelberger et al. demonstrating a reduced incidence of CHF since 1993/1994 and a small but significant improvement in annual mortality. It is striking that these studies from two separate European Countries show such consistent temporal trends, yet despite these improvements the 1-year mortality rate remains in excess of 25%.

The report by Schaufelberger et al. addresses some of the criticisms originally levied at the study from Scotland, which at the time was a unique finding and after all ‘one swallow doesn't make a summer’.5However, as the populations of Scotland and Sweden may not be that genetically heterogeneous, one could argue that some doubt remains regarding the generalizability of the findings to other nations, such as France.5

2. How valid are the data

Studies like those of Schaufelberger et al. and MacIntyre et al. are open to a number of criticisms. The use of clinical coding to determine trends in diagnosis, hospitalization and prognosis may be influenced by a number of external factors. These factors include changes with time, in investigative tools, diagnostic criteria and/or the level of clinical suspicion. These uncertainties are further confounded by a lack of agreement on a definition of heart failure and variations between physicians, other health care staff and coders. Despite these reservations the data of Schaufelberger et al. confirm the previous report and are further strengthened by the authors attempts to validate cardiovascular diagnoses in subsets of patients. While these reports do not tell us about ambulant patients with CHF, who have never been admitted to hospital, they do provide valuable information on patients with at least one admission to hospital. The data also suggest that at the index admission our treatment strategies must continue to evolve, as annual mortality rates are still very high at approximately25%.

3. Assessing prognosis in patients with heart failure

It is emerging that patients with CHF are a heterogeneous group. Within the population described by Schaufelberger et al. are patients with preserved ejection fractions, substantial conduction defects, severe systolic impairment who may have a surprisingly good prognosis and patients with mild systolic impairment who may die suddenly or rapidly decompensate. A major challenge facing doctors and researchers with an interest in heart failure is the development of reproducible and accurate methods to identify patients at high risk of death. Of particular interest are patients with CHF and a preserved ejection fraction. Population studies have demonstrated that up to 40% of patients with CHF have preserved left ventricular systolic function.6The prognosis of these patients is controversial but probably better than those with impaired systolic function. We recently provided data suggesting that patients with heart failure and an ejection fraction >50% have a mortality of 25% at 5 years, whereas patients with ejection fractions <50% have mortality of almost twice this figure.7It would be of interest and value to obtain similar data to that of Schaufelberger et al. to identify the natural history of patients with CHF and a preserved ejection fraction. At present, information regarding prevalence, incidence and evidence-based management for such patients is lacking. Do they benefit similarly from the improvement in overall mortality demonstrated in Scotland and Sweden? Do their admission rates differ? Are theyolder? Are more of them female? All of these questions await definitive answers.

4. Perspective

The study by Schaufelberger et al. is welcome for a number of reasons; firstly it demonstrates in a second large European population that we are making progress in the treatment of CHF, reducing hospital admissions and both in-hospital and out of hospital mortality. It also illustrates that while we are beginning to understand how to treat CHF much work remains to be done. The data are reported up to 2000, it is therefore unlikely, even in Sweden, that the use of beta-blockers and spironolactone had become widespread, as the landmark trials of these agents reported in 1999. The database used by Schaufelberger et al. thus will provide an ideal tool with which to continue to assess the impact of large randomized controlled trials on heart failure patients in the ‘real world’. We await these studies with interest. In the meantime studies should be performed aimed at identifying markers of adverse prognosis in different subpopulations of patients with heart failure such as women, the elderly, those with a preserved ejection fraction or of defined ethnicity. Such studies will allow us to identify the most effective care and tailor our treatment to individuals better than our current ‘one-size fits all’ strategy.

In summary, the insight to the improvement in the epidemiology of CHF provided by Schaufelberger et al. is extremely encouraging. If we continue our current course the future will be even brighter tomorrow!

Footnotes

{dagger} doi:10.1016/j.ehj.2003.12.012 Back

References

  1. Stewart S, MacIntyre K, Hole DJ et al. More ‘malignant' than cancer? Five-year survival following a first admission for heart failure. Eur J Heart Fail. 2001;3:315–322.[CrossRef][Medline]
  2. Schaufelberger M, Swedberg K, Koster M et al. Decreasing one year mortality and hospitalisation rates for heart failure in Sweden. Data from the Swedish Hospital Discharge Registry. Eur Heart J. 2004;25:300–307.[Abstract/Free Full Text]
  3. Stewart S, MacIntyre K, MacLeod MM et al. Trends in hospitalization for heart failure in Scotland, 1990–1996. An epidemic that has reached its peak? Eur Heart J. 2001;22:209–217.[Abstract/Free Full Text]
  4. MacIntyre K, Capewell S, Stewart S et al. Evidence of improving prognosis in heart failure: trends in case fatality in 66 547 patients hospitalised between and 1995. Circulation. 2000;102:1126–1131.[Abstract/Free Full Text]
  5. Zannad F. Have we jugulated the epidemic of heart failure? One swallow does not make a summer. Eur Heart J. 2001;22:188–190.[Free Full Text]
  6. Vasan RS, Larson MG, Benjamin EJ et al. Congestive heart failure in subjects with normal versus reduced left ventricular ejection fraction: prevalence and mortality in a population based cohort. J Am Coll Cardiol. 1999;33:1948–1955.[CrossRef][Medline]
  7. MacCarthy PA, Kearney MT, Nolan J et al. Prognosis in heart failure with preserved left ventricular systolic function: prospective cohort study. Br Med J. 2003;327:78–79.[Free Full Text]

Related articles in EHJ:

Decreasing one-year mortality and hospitalization rates for heart failure in Sweden: Data from the Swedish Hospital Discharge Registry 1988 to 2000
Maria Schaufelberger, Karl Swedberg, Max Köster, Måns Rosén, and Annika Rosengren
EHJ 2004 25: 300-307. [Abstract] [Full Text]