People with type 1 diabetes have a substantially increased risk of heart failure, according to a Swedish study published online September 18 in Lancet Diabetes & Endocrinology.

The research also found that poor glycemic control and impaired renal function increase the risk of heart failure in this form of diabetes.

Heart-failure experts have been warning for the past few years that diabetics have an increased risk of heart failure, but most prior work has not distinguished between type 1 and type 2 diabetes.

This new study is the first to look specifically at the likelihood of heart failure in people with type 1 diabetes, compared with the general population, say the authors.

"Our chief finding was that, even if still uncommon, people with type 1 diabetes had four times the risk of heart failure over an average of 8 years, compared with persons without type 1 diabetes from the general population," commented lead author Annika Rosengren, MD, PhD, professor of medicine at Sahlgrenska University, in Göteborg, Sweden.

And "in the presence of poorly controlled diabetes, risk was more than 10 times that of controls, whereas heavy leakage of protein into the urine [macroalbuminuria, which indicates impaired renal function] was associated with more than 15-fold increase in risk," she pointed out.

Diabetes represents an independent risk factor for heart failure. Although rare in youth, the implications of heart failure are "serious" when it does develop, according to Dr Rosengren.

"Because heart failure usually occurs at an advanced age, when type 2 diabetes is by far the predominant type, the role of type 1 diabetes — the type that afflicts children, adolescents, and young adults and that is not related to obesity or lifestyle — has never been investigated," she explained.

Doctors should therefore be aware of this increased risk and carry out appropriate investigations when confronted with symptoms suggestive of heart failure in people with type 1, she added.

In an accompanying editorial, Robert Gilbert, MD, PhD, head of the division of endocrinology at St Michael's Hospital in Toronto, Ontario, agrees, pointing out that people who have diabetes, whether type 1 or type 2, experience "accelerated aging."

"Consistent with heart failure as a disease of elderly people and the premature aging effect of diabetes, the relative risk conferred by type 1 diabetes is magnified in this comparatively young age group [in this study]," he writes, adding that heart failure in type 1 diabetes is "fatal, forgotten, and frequent."

Women With Type 1 at Higher Risk of Heart Failure Than Men

The prospective, case-control study included all individuals with type 1 diabetes logged in the Swedish National Diabetes Registry between January 1998 and December 2011, which includes almost all people with type 1 diabetes in that country.

Researchers identified hospital admissions for heart failure using ICD 10 codes and matched these by age, sex, and county to controls from the Swedish general population.

The analysis included 33,402 type 1 diabetics, with a mean age of 35 years, mean diabetes duration of 20.1 years, and mean baseline HbA1c of 8.2%. Controls numbered 166,228.

Over an average of 8 years, 3% (n = 1062) of type 1 diabetics had hospital admissions for heart failure, compared with 1% (n = 1325) of those in the general population. After adjustment for age, sex, diabetes duration, birth in Sweden, educational level, and baseline comorbidities, those with type 1 diabetes had over a four-times-greater risk of heart failure compared with controls (adjusted hazard ratio [HR], 4.69). Women with type 1 diabetes had higher risk of heart failure than men with type 1 diabetes (adjusted HR, 6.36 and 4.07, respectively, compared with controls).

The risk of heart failure was over 10 times greater in type 1 diabetics with poor glycemic control and up to 18 times greater in those with albuminuria, compared with controls. This risk increased as glycemic control and renal function worsened.

Even type 1 diabetics with well-controlled diabetes and normal renal function had an increased risk of heart failure.

Compared with the general population, the risk was still more than double with well-controlled diabetes (adjusted HR, 2.16) and three times greater with normal renal function (adjusted HR, 3.38).

Doctors Must Be Aware of Heart Failure Risk, Talk to Each Other

"Diabetologists and other health professionals involved in the care of individuals with diabetes type 1 need to be aware of the increased risk [for heart failure] in these patients," Dr Rosengren advised.

"Appropriate investigations, like echocardiography and lab tests, should be carried out if there are symptoms such as breathlessness on exertion or unexplained tiredness.

"Heart failure in the young is frequently misdiagnosed as asthma, with delay of appropriate treatment. The knowledge that persons with type 1 diabetes are particularly vulnerable to heart failure should ensure that this does not happen," she emphasized.

"The combination of these two chronic conditions has dire prognostic implications," she and her colleagues stress.

In his editorial, Dr Gilbert notes that the study raises several questions for practicing clinicians. For example, should patients with lower exercise tolerance be considered out of shape, or could it be a sign of heart failure?

Should such patients have echocardiograms and detailed reports of diastolic and systolic function? And how should clinicians act on this information, especially given no evidence-based treatment for diastolic dysfunction?

"A good first step might be for diabetologists and cardiologists to meet up and discuss the current state of affairs, with a renewed interest in the effect of the various antihyperglycemic drugs at our disposal," he proposes.

"This discussion could be followed by the planning of collaborative research endeavors…as well as investigations into new approaches to prevent the development of overt heart failure among patients at highest risk and in those with subclinical echocardiographic evidence of cardiac dysfunction."The risk of heart failure was over 10 times greater in type 1 diabetics with poor glycemic control and up to 18 times greater in those with albuminuria, compared with controls. This risk increased as glycemic control and renal function worsened.

Even type 1 diabetics with well-controlled diabetes and normal renal function had an increased risk of heart failure.

Compared with the general population, the risk was still more than double with well-controlled diabetes (adjusted HR, 2.16) and three times greater with normal renal function (adjusted HR, 3.38).

Doctors Must Be Aware of Heart Failure Risk, Talk to Each Other

"Diabetologists and other health professionals involved in the care of individuals with diabetes type 1 need to be aware of the increased risk [for heart failure] in these patients," Dr Rosengren advised.

"Appropriate investigations, like echocardiography and lab tests, should be carried out if there are symptoms such as breathlessness on exertion or unexplained tiredness.

"Heart failure in the young is frequently misdiagnosed as asthma, with delay of appropriate treatment. The knowledge that persons with type 1 diabetes are particularly vulnerable to heart failure should ensure that this does not happen," she emphasized.

"The combination of these two chronic conditions has dire prognostic implications," she and her colleagues stress.

In his editorial, Dr Gilbert notes that the study raises several questions for practicing clinicians. For example, should patients with lower exercise tolerance be considered out of shape, or could it be a sign of heart failure?

Should such patients have echocardiograms and detailed reports of diastolic and systolic function? And how should clinicians act on this information, especially given no evidence-based treatment for diastolic dysfunction?

"A good first step might be for diabetologists and cardiologists to meet up and discuss the current state of affairs, with a renewed interest in the effect of the various antihyperglycemic drugs at our disposal," he proposes.

"This discussion could be followed by the planning of collaborative research endeavors…as well as investigations into new approaches to prevent the development of overt heart failure among patients at highest risk and in those with subclinical echocardiographic evidence of cardiac dysfunction."

Lancet Diabetes Endocrinol. Published online September 18, 2015.

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Nyhetsinfo

ABSTRACT

 

Summary

Background

Diabetes is an established risk factor for heart failure, but because nearly all heart failure occurs in older individuals, the excess risk and risk factors for heart failure in individuals with type 1 diabetes are not known. We aimed to determine the excess risk of heart failure in individuals with type 1 diabetes overall and by different levels of glycaemic control and albuminuria.

Methods

In this prospective case-control study, we identified all individuals with type 1 diabetes registered in the Swedish National Diabetes Registry between Jan 1, 1998, and Dec 31, 2011, and five controls randomly selected from the general population for each patient, matched according to age, sex, and county, and compared them with respect to subsequent hospital admissions for heart failure, with hazard ratios calculated with Cox regression.

Findings

In a cohort of 33 402 patients (mean age at baseline 35 years [SD 14], 15 058 [45%] women, and mean duration of diabetes 20·1 years [SD 14·5]), over a mean follow-up of 7·9 years, 1062 (3%) patients were admitted to hospital with a diagnosis of heart failure, compared with 1325 (1%) of 166 228 matched controls over 8·3 years, giving a HR 4·69 (95% CI 3·64–6·04), after adjustment for time-updated age, sex, time-updated diabetes duration, birth in Sweden, educational level, and baseline comorbidities. Worse glycaemic control was associated with increased risk of heart failure in a graded fashion, and so was the presence of albuminuria. Risk of heart failure was also increased among those with well controlled diabetes (adjusted HR 2·16 [95% CI 1·55–3·01]) and in those with no albuminuria (3·38 [2·51–4·57]), but not in the subgroup both well-controlled and with normoalbuminuria (1·59 [0·70–3·58]).

Interpretation

Individuals with type 1 diabetes had a four-times increase in the risk of being admitted to hospital with heart failure compared with population-based controls. Poor glycaemic control and impaired renal function substantially increased the risk of heart failure.

 

EDITORIAL

 
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