Diabetes, Heart Failure Hospitalization, and Death

Study Questions:

What is the incidence and case-fatality of heart failure (HF) hospitalizations in diabetics?

Methods:

The study authors examined the incidence and case-fatality of HF hospitalizations in the entire population aged ≥30 years residing in Scotland over a 10-year period from January 2004-December 2013. HF hospitalizations were defined as incident if these were the first to occur on or after January 2004, where no previous HF hospitalization had been recorded during the preceding 10 years. They linked date and type of diabetes diagnosis to HF hospitalizations and deaths using the national Scottish registers. They estimated incidence rates and case-fatality in regression models (quasi-Poisson and logistic regression, respectively). They adjusted all estimates for age, gender, socioeconomic status, and calendar year.

Results:

Over the study period, among 3.25 million people (3,066,253 people without a diagnosis of diabetes, 136,042 with a diagnosis of type 2 diabetes, and 18,240 with a diagnosis of type 1 diabetes), there were 91,429, 22,959 and 1,313 incident HF events among those without diabetes, with type 2, and type 1 diabetes, respectively. The crude incidence rates of HF hospitalization were therefore 2.4, 12.4, and 5.6 per 1,000 person-years for these three groups. The study authors found that the age- and sex-adjusted rates of incident HF hospitalization were around twofold higher in people with diabetes, regardless of type, compared to those without diabetes. Relative differences were smallest for older men, in whom the difference was nonetheless large (men aged 80 years, rate ratio [RR], 1.78; 95% confidence interval [CI], 1.45-2.19). The impact of diabetes on HF risk was greater at older ages and in men. The absolute difference in 1-year risk of HF admission in 80-year-old men (the group with the smallest relative difference) with and without diabetes was 2.5%. For the same comparison, but in 40-year-old women, the difference was <0.5%. Rates declined similarly, by 0.2% per calendar year, in people with type 2 diabetes and without diabetes. Rates fell faster, however, in those with type 1 diabetes (2.2% per calendar year, RR for type 1/calendar-year interaction, 0.978; 95% CI, 0.959-0.998). Thirty-day case-fatality was similar among people with type 2 diabetes and without diabetes, but was higher in type 1 diabetes for men (odds ratio [OR], 0.96; 95% CI, 0.95-0.96) and women (OR, 0.98; 95% CI, 0.97-0.98). Case-fatality declined over time for all groups (3.3% per calendar year, OR per calendar year, 0.967; 95% CI, 0.961-0.973).

Conclusions:

The study authors concluded that despite falling incidence, particularly in type 1 diabetes, HF remains around twofold higher than in people without diabetes, with higher case-fatality in those with type 1 diabetes. These findings support the view that HF is an under-recognized and important complication in diabetes, particularly for type 1 disease.

Perspective:

This is an important study because it suggests that diabetes mellitus is an important risk factor for HF hospitalizations. It would be interesting to know whether this is a risk marker or simply a reflection of patients who are more likely to be “noncompliant,” particularly with diet (both regarding salt intake and diabetic diet).

Clinical Topics: Diabetes and Cardiometabolic Disease, Geriatric Cardiology, Heart Failure and Cardiomyopathies, Prevention, Acute Heart Failure, Diet

Keywords: Diabetes Mellitus, Type 1, Diabetes Mellitus, Type 2, Diet, Geriatrics, Heart Failure, Hospital Mortality, Hospitalization, Metabolic Syndrome X, Risk Factors, Secondary Prevention


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