Lower HbA1c Post-PCI Promotes Better Outcomes in Diabetes

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Patients with diabetes represent more than a quarter of patients undergoing PCI.
Patients with diabetes represent more than a quarter of patients undergoing PCI.

Glycemic control after percutaneous coronary intervention (PCI) was associated with fewer cardiac and cerebrovascular events in patients with diabetes, according to the results of an observational study.1

Although intensive glycemic control has been found to reduce microvascular complications in patients with type 2 diabetes, it is unclear whether it also reduces macrovascular complications in these individuals.2,3 In addition, findings regarding the effect of glycemic control on cardiovascular outcomes after PCI have been mixed.

Patients with diabetes represent more than one-fourth of patients who undergo PCI, and their outcomes are worse than patients without diabetes, underscoring the importance of optimal glycemic control in this group.4 To that end, the current researchers examined the link between glycated hemoglobin A (HbA1c) levels after PCI and long-term cardiovascular outcomes in 980 patients with type 2 diabetes undergoing PCI using drug-eluting stents.

Baseline, imaging, and clinical outcome data were collected prospectively, and follow-up occurred at 1, 6, and 12 months after PCI and then each subsequent year. The primary outcome was major adverse cardiac and cerebrovascular events (MACCE) during the follow-up period. Patients were divided into 2 groups: those with HbA1c levels <7.0 (n=489) and those with levels ≥7.0 (n=491) at 2 years post-PCI.

The results showed a lower 7-year incidence of MACCE in the lower-HbA1c group compared with the higher-HbA1c group (26.9% vs 40.3%; adjusted hazard ratio [HR], 0.75; 95% CI, 0.57-0.98; P =.03). A lower 7-year incidence of MACCE was still observed in the lower-HbA1c group after a propensity score-matched analysis (27.5% vs 37.4%; HR, 0.71; 95% CI, 0.52-0.97; P =.03), mainly because of a decrease in repeat revascularization (19.9% vs 29.5%; HR, 0.66; 95% CI, 0.47-0.93; P =.02).

Subgroup analyses revealed that the benefit of glycemic control for MACCE was greater among patients with a residual SYNTAX score (Synergy Between PCI With Taxus and Cardiac Surgery score) >4 compared with patients with a score ≤4 (Pinteraction =.004).

"Taken together, our results suggest that glycemic control after PCI may improve long-term outcomes in patients with diabetes mellitus independent of HbA1c level at the time of PCI," the researchers concluded. In addition, high HbA1c levels detected 2 years post-PCI may indicate a risk of adverse events, particularly repeat vascularization. "We think that our study adds new and important information on strategies for glycemic control after PCI in [patients with diabetes]."

References

1. Hwang JK, Lee SH, Song YB, et al. Glycemic control status after percutaneous coronary intervention and long-term clinical outcomes in patients with type 2 diabetes mellitus [published online April 3, 2017].  Circ Cardiovasc Interv. doi:10.1161/CIRCINTERVENTIONS.116.004157

2. UK Prospective Diabetes Study (UKPDS) Group. Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes (UKPDS 33). Lancet. 1998;352(9131):837-853.

3. Gerstein HC, Miller ME, Byington RP, et al; Action to Control Cardiovascular Risk in Diabetes Study Group. Effects of intensive glucose lowering in type 2 diabetes. N Engl J Med. 2008;358(24):2545-2459. doi:10.1056/NEJMoa0802743

4. Beckman JA, Paneni F, Cosentino F, Creager MA. Diabetes and vascular disease: pathophysiology, clinical consequences, and medical therapy: part II. Eur Heart J. 2013;34(31):2444-2452. doi:10.1093/eurheartj/eht142

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