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Impact of diabetes on long-term mortality following multivessel percutaneous interventions: an insight into optimal
Shikhar Agarwal1, Navkaranbir Singh Bajaj, Tarique Zaman
1Sones Cardiac Catheterization Laboratories, Heart and Vascular Institute, J2-3, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, United States.
Insights
Diabetics with coronary artery disease (CAD) undergoing percutaneous coronary intervention (PCI) show higher mortality with bare metal stents (BMS) compared to drug-eluting stents (DES). Generalized estimating equations (GEE) provide optimal analysis for this clustered data.
Area of Science:
- Cardiology
- Biostatistics
- Public Health
Background:
- Drug-eluting stents (DES) offer better long-term outcomes than bare metal stents (BMS) for diabetics with coronary artery disease (CAD).
- Statistical analysis of stent data presents challenges due to heterogeneity.
- Percutaneous coronary intervention (PCI) data involves complex spatial and temporal clustering.
Purpose of the Study:
- To compare long-term mortality between DES and BMS in diabetic CAD patients undergoing PCI.
- To identify the optimal statistical strategy for analyzing clustered PCI data.
- To evaluate the impact of stent type on mortality using robust statistical methods.
Main Methods:
- Retrospective analysis of a PCI registry (2003-2009) including diabetics with CAD undergoing multi-vessel PCI.
- Assessment of long-term mortality via the Social Security Death Index.
- Application and comparison of six different statistical analytical strategies, including Generalized Estimating Equations (GEE).
Main Results:
- The study included 756 diabetics with 1568 DES and 336 BMS interventions.
- Significant differences in outcomes were observed across analytical methods.
- The Generalized Estimating Equation (GEE) approach with an autoregressive correlation structure proved robust for clustered data.
- Diabetics receiving BMS-PCI had a 47% higher hazard of long-term mortality compared to those receiving DES-PCI (Hazard Ratio: 1.47, 95% CI: 1.04-2.09).
Conclusions:
- Complex clustering in PCI data can lead to misinterpretation.
- GEE with an autoregressive correlation matrix and robust variance is the optimal method for analyzing clustered PCI data.
- Diabetics undergoing BMS-PCI face a significantly higher mortality risk compared to those undergoing DES-PCI.
Background:
Several studies have demonstrated better long-term outcomes with drug eluting stents (DES) as compared to bare metal stents (BMS) among diabetics with coronary artery disease (CAD). A significant heterogeneity exists with respect to the optimal statistical strategy to analyze stent related data.
Methods:
We used our percutaneous intervention (PCI) registry to identify all diabetics with CAD, who underwent PCI on two or more vessel territories between 2003 and 2009. Long-term mortality was assessed using the social security death index. Six different analytical strategies were applied.
Results:
A total of 1568 DES and 336 BMS interventions were encountered in 756 diabetics. Considerable differences were observed in the results between the methods applied. Generalized estimating equation (GEE) approach with an autoregressive correlation structure (GEE) was a robust method to account for the cluster structure, since the measurements taken through time on the same person were assumed to be highly correlated, if they were spaced more closely in time. Diabetics undergoing PCI with BMS had a significantly higher long-term mortality as compared to the patients undergoing DES-PCI [Hazard ratio (95% CI): 1.47 (1.04-2.09)].
Conclusion:
There is a great potential for erroneous interpretation of PCI data due to complex spatial and temporal clustering. Use of GEE with autoregressive correlation matrix and robust variance is most optimal to account for the clustered nature of the PCI related data. Using GEE, we observed that there is a 47% (4%-119%) higher hazard for mortality among diabetics undergoing BMS-PCI as compared to diabetics undergoing DES-PCI.
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