HEART FAILURE PREVALENCE

This just in:

2% OF ADULTS IN EUROPE, NORTH AMERICA AND ISRAEL HAVE HEART FAILURE.

A review in “News-Medical.Net “, by Emily Henderson, B.Sc., in
“Medical Home Life Sciences” news service, dated 2/14/23, of an article
by Norhammar et al., printed in the BMJ’s “heart” section and entitled
“Prevalence, outcomes and costs of a contemporary, multinational population with heart failure”, doi.org/10.1136/heartjnl-2022-321702 came into my newsfeed, today.

This review has been publicized by 36 news outlets, blogged by 2 and tweeted by 61.

I have paraphrased Ms. Henderson’s article, below. In essence, it reads as follows:
“Up to 2% of adults in Europe, North America, and Israel have heart failure, and are at high risk of death.
The number of cases is expected to rise as populations age.
The cost is 1-2% of annual healthcare budgets.”

This statement is based on digital health records for 11 countries, as published online in the BMJ’s “Heart” section.
The BMJ article goes on to say that the findings are not generally representative.
Nevertheless, the statistics provided are of significant interest.

The authors did a study to estimate the prevalence, unfavorable outcomes, and costs of hospitalisation for heart failure in Sweden, Norway, the UK, Belgium, Germany, Switzerland, Italy, Spain, Portugal, Israel and Canada.
Pooled data for 600,000 +  people with heart failure between 2018 and 2020 were examined.

The average age was 75 years.
45% were women, 55% were men.  
42% of patients had preserved left ventricular ejection fraction.
Nearly half (49%) had ischaemic heart disease, 44% had atrial fibrillation and a third (34.5%) had diabetes.
Kidney function was measured in 170,000 cases and (49%) had moderate to severe chronic kidney disease.

Cumulative costs of hospital care was calculated for each person for up to 5 years.
Episodes of illness were cumulatively reported per 100 patient years (the % who had an annual episode).
The prevalence of heart failure among adults was 1-2% across all 11 countries and more than 32 million people.
The highest prevalence was in Portugal (just under 3%); the lowest was in the UK (almost 1.5%).

Risks of annual hospital admission and costs, were highest for those with CKD (19%).
The annual death rate was 13%.

At the foot of the article is the following statement:
“No data are available. The data sources used are all underlying local, ethical and privacy restrictions for data transfer abroad or into public domain, limiting data availability on request. Therefore, the data that support the findings of this study are not available on request.”

Interestingly, the article as written in BMJ’s “heart” section does not contain details of blood test results and myxedema, one of the commonest findings in heart failure, , is not mentioned.

COMMENT

This article warrants comment because no mention of thyroid disease and no report of thyroid function, in those affected by heart failure, appears in its pages.

It is on the one hand remarkable that a paper written in 2023 does not mention important investigations and on the other, it is discouraging because a “thyroid profile” should be obtained routinely as part of the investigation of all illnesses.

Our hearts need to a supply of Triiodothyronine (T3, not T4).
Because myocytes have poor deiodinase activity, as noted by Kline and Danzi  [2], T3 from the serum has to be transported into them.
Hypothyroidism can produce bradycardia, impaired contractility, impaired diastolic filling, increased systemic vascular resistance, diastolic hypertension, and endothelial dysfunction, as noted by P Rastogi et al. [1]. Patients with heart failure who have normal thyroid glands, normal T4 and unremarkable TSH, may have low levels of T3 and an elevated reverse T3: in these, either “subclinical (intracellular) Hypothyroidism” ** is the reason for heart failure, or the heart failure is the cause of subclinical hypothyroidism.

In any event, the functional diagnosis is cardiomyopathy due to “T3 starvation” in the Cardiomyoytes, so treatment with Triiodothyronine will return heart function to normal.
The success of treatment with thyroxine on the other hand, will depend on which condition is primary: if the base problem is intracellular hypothyroidism, thyroxine will be detrimental: if the base problem is heart failure for other reasons, thyroxine will be helpful.

** Studies have shown that as in the sick-euthyroid syndrome, A.K.A. Low T3 syndrome, functional hypothyroidism, intracellular hypothyroidism etc., which occurs in nonthyroidal illnesses like sepsis, the TSH and T4 may be normal, while serum T3 is at minimum and reverse T3 is elevated.
This is due to elimination of T3 within the cells, by blockade of Deiodinase 1 and activation of Deiodinase 3.

A case report illustrating this detailed the progress of a young female with DILATED CARDIOMYOPATHY CAUSED BY HYPOTHYROIDISM and cured with T4 [2], which concluded that “Low serum T3 in these patients strongly predicts all-cause and cardiovascular mortality” and “The most consistent cardiac abnormality recognized in patients with overt hypothyroidism is impairment of LV diastolic function characterized by slowed myocardial relaxation and impaired early ventricular filling.”

[1] Thyroid Disease and the Heart, by Irwin Klein and Sara Danzi , in “Circulation”, 9 Oct 2007, 116:1725–1735 https://doi.org/10.1161/CIRCULATIONAHA.106.678326 .

[2] Hypothyroidism-induced reversible dilated cardiomyopathy; ,
by P Rastogi, A Dua, S Attri, and H Sharma, J Postgrad Med. 2018 Jul-Sep; 64(3): 177–179. doi: 10.4103/jpgm.JPGM_154_17, PMCID: PMC6066629PMID: 29992912 , https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6066629/

THE BOTTOM LINE

(1) Editors should try to avoid printing articles with insufficient documentation.
(2) Readers should not draw important conclusions from such articles.