Does Larger Infarct Size Explain the Worse Prognosis of Diabetic Patients Undergoing Primary PCI for STEMI? Patient-Level Pooled Analysis of 10 Randomized Trials

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¹Clinical Trials Center, Cardiovascular Research Foundation, USA
²Institute for Clinical Research and Health Policy Studies, Tufts Medical Center, USA
³German Center for Cardiovascular Research, University Heart Center Lübeck, Germany
⁴Duke University Medical Center, Duke University, USA
⁵Department of Cardiology,, New-York Presbyterian Hospital Columbia University Medical Center, USA
⁶Mary Imogene Bassett Hospital, Mary Imogene Bassett Hospital, USA

Diabetes(DM) is associated with worse outcomes after primary PCI(pPCI). Contrasting results were reported on impact of DM on MI infarct size(IS). We sought to investigate the association between DM and IS and whether larger IS underlies the prognosis for diabetic patients in STEMI.

Patient-level data were pooled from ten randomized pPCI trials in which IS (% of total LV mass) was assessed within one month after randomization by cardiac magnetic resonance (CMR) imaging or technetium-99m sestamibi SPECT. Multivariable linear regression analysis assessed the relationship between DM and IS. The association of DM with death or heart failure hospitalization (D/HF) within 1 year was evaluated using Cox proportional hazards regression. Models were adjusted for multiple known risk factors.

456/2622 patinets (17%) had DM. DM was associated with slightly larger IS, although not statistically significant (adjusted difference 3.06%, 95% CI, -0.53% to 6.67%, p=0.08). In the entire population, IS was strongly associated with the 1-year rate of D/HF (adjusted HR (per 5% increase) 1.20 95% CI 1.19–1.21, p<0.0001). Patients with vs. without DM had a higher 1-year rate of D/HF (7.7% vs. 3.8%, p<0.001; adjusted HR 1.39 (95% CI 1.01 to 1.92, p=0.04). This excess risk was no longer significant when IS was included as a covariate in the model (adjusted HR 1.31, 95% CI 0.95 to 1.79, p=0.10). No interaction was present between the presence of DM and IS on the risk of D/HF (p=0.68).

DM was associated with a trend towards greater IS which may in part contribute to their worse prognosis compared to pts without DM. Infarct size did not differentially impact 1-year outcomes in patients with vs. those without DM.