Diabetes may blunt response to CRT in Asians with HF
The coexistence of diabetes mellitus (DM) in Asian patients with heart failure (HF) who were receiving cardiac resynchronization therapy (CRT) attenuated CRT-induced left ventricular (LV) reverse modelling — a predictor of event-free survival — and was associated with worse clinical outcomes compared with patients without T2D, the PEACH* study shows.
“This is particularly pertinent given that DM is threefold more common among Southeast Asian patients with HF compared with [Caucasians],” said the researchers led by Dr Eugene Tan from the National University Heart Centre, Singapore.
The prospective observational study enrolled 161 consecutive Asian patients with HF (mean age 66.7 years, 22 percent females, 51 percent with DM of which all were type 2 diabetes) who were receiving CRT from 2011 to 2017. The patients were followed up every 6 months. They were classified as CRT responders or super-responders if their end-systolic volume index decreased by ≥15 percent and ≥30 percent, respectively. [Am J Cardiol 2019;doi:10.1016/j.amjcard.2019.06.004]
After a mean follow-up of 3.3 years, 52 percent of the HF patients achieved a CRT response, of which 35 percent were super-responders. Among those who responded, there were more patients without diabetes than those with diabetes (62 percent vs 43 percent; p=0.01 for responders and 46 percent vs 26 percent; p=0.008 for super-responders), based on the extent of LV reverse remodelling.
According to the researchers, “CRT is an established therapeutic modality in improving survival through its ability to reverse LV remodelling.”
However, patients with diabetes were at least 56 percent less likely to attain reverse remodelling with CRT than those without diabetes.
Patients with diabetes were also more than twice as likely as those without diabetes to experience the primary composite outcome of hospitalization for HF or all-cause mortality (61 percent vs 41 percent, hazard ratio [HR], 2.29, 95 percent confidence interval [CI], 1.22–4.31).
Analysis of the overall population revealed that response to CRT (HR, 0.27, 95 percent CI, 0.14–0.51 for CRT response and HR, 0.13, 95 percent CI, 0.06–0.28 for super-response) was associated with a reduced risk of the primary outcome compared with nonresponse.
Furthermore, the greater the extent of CRT response (corresponding to LV reverse remodelling), the lower the risk of the primary outcome — with CRT responders showing a 50 percent lower risk and super-responders a 73 percent lower risk of the composite events.
“The extent of reverse remodelling post-CRT is the strongest predictor of event free survival [among other factors such as sex, age, and the types of antihypertensives used],” said Tan and co-authors. “[However,] the presence of DM is detrimental to the CRT recipient … by limiting the extent of reverse remodelling after CRT implantation.”
Moreover, diabetes was associated with an increased risk of microvascular and macrovascular complications, which were all detrimental to CRT recipients and can contribute to poor clinical outcomes among the patients, according to the researchers.