Examining the Impact of Central Obesity on HF Outcomes Among Adults With T1D

Central obesity was associated with an increased risk of heart failure (HF) hospitalization or death among adults with type 1 diabetes (T1D), according to study results published in Cardiovascular Diabetology.

Obesity is an established risk factor for HF in the general population, and although the prevalence of obesity has increased among those with T1D, “studies concerning HF in this population are scarce,” authors explained.

In addition to obesity, diabetes is also a risk factor for HF, and both are risk factors for diabetic nephropathy (DN), which constitutes another important risk factor of HF.

Researchers used the waist-height ratio (WHtR) and body mass index (BMI) measurements to investigate the association between body fat distribution and risk of hospitalization or death due to HF in adults with T1D at different stages of DN.

Data were gleaned from the observational, longitudinal Finnish Diabetic Nephropathy Study. The study had a follow-up period of 16.4 years (interquartile range, 12.4-18.5), while WHtR was used to determine central obesity and BMI to measure general obesity.

A total of 4668 individuals with T1D were included in the analysis and completed baseline visits between 1997 and 2017. “DN stage was based on the individuals’ urinary albumin excretion rate (UAER) in timed overnight or 24 h urine (mg/24 h) collections,” researchers explained.

Over the course of the follow-up period, 323 incident cases of hospitalization or death due to HF occurred.

Analyses revealed:

• From 308 hospitalizations due to HF, 35 resulted in death and 15 deaths occurred without previous hospitalization
• The WHtR showed a stronger association with the outcome (HR 1.51; 95% CI, 1.26–1.81; z = 4.40) than BMI (HR 1.05; 95% CI, 1.01–1.08; z = 2.71)
• Glycated hemoglobin (HR 1.35; 95% CI, 1.24–1.46; z = 7.19) was the most relevant modifiable risk factor for the outcome whereas WHtR ranked 3rd
• According to the DN stage, 3.4% (n = 112), 9.6% (n = 62) and 21.3% (n = 149) of the incident cases occurred in individuals with normo-, micro- and macroalbuminuria stages, respectively
• Comparing individuals above versus below the normal threshold at the microalbuminuria stage, individuals with central obesity (WHtR ≥ 0.5) had a 3-fold higher risk (HR 2.98; P = .002) of HF hospitalization or death than those without central obesity
• Individuals with microalbuminuria but no central obesity had a similar risk of the outcome as those with normoalbuminuria
• General obesity was associated with the outcome only at the macroalbuminuria stage

“We showed that WHtR, a hallmark of central obesity, is a relevant and modifiable risk factor among the most important well-known risk factors for HF,” researchers said.

They offered 2 explanations as to why WHtR was not an important HF risk factor at the normoalbuminuria stage. Namely, individuals with T1D in this stage have a lower percentage of visceral adipose tissue compared with those with albuminuria, reducing the power of central obesity to predict the outcome.

In addition, patients with normoalbuminuria lack albuminuria, an important risk factor for HF. It is possible, “central obesity may need the presence of albuminuria to impact the risk of HF hospitalization or death,” authors explained.

Lack of data on HF stage and its classification as reduced or preserved ejection fraction mark a limitation to the study. As the study population was a homogenous white Finnish population, results may also not be generalizable to other ethnicities.

However, “the WHtR, a hallmark of central obesity, may be considered in the routine consultations of people with T1D for screening high-risk individuals,” researchers concluded.

Reference

Parente EB, Harjutsalo V, Forsblom C, Groop P, and on behalf of The FinnDiane Study Group. The impact of central obesity on the risk of hospitalization or death due to heart failure in type 1 diabetes: a 16-year cohort study. Cardiovasc Diabetol. Published online July 27, 2021. doi:10.1186/s12933-021-01340-4