Influence of Diabetes on Inappropriate and Appropriate ICD therapy and Mortality in the MADIT-RIT Trial
Background—The relationship between diabetes and risk of inappropriate or appropriate therapy in patients receiving ICD and resynchronization therapy has not been investigated thoroughly. The effect of innovative ICD programming on therapy delivery in these patients is unknown.
Methods and Results—The MADIT-RIT trial randomized patients with a primary prophylactic ICD indication to three different types of ICD programming: conventional programming with a VT zone 170-199 bpm (A), high-rate cut-off with a VT zone ≥200 bpm (B), or 60 sec delayed therapy (C). The end points of inappropriate therapy, appropriate therapy and death were assessed among 485 patients with and 998 without diabetes. Innovative ICD programming reduced the risk of inappropriate therapy irrespective of diabetes, although a trend towards a more pronounced effect of high-rate cut-off programming was seen in patients without diabetes (p for interaction 0.06). Diabetes was associated with decreased risk of inappropriate therapy (HR= 0.54, 95% CI: 0.36-0.80, p=0.002) and increased risk of appropriate therapy (HR=1.58, 95% CI: 1.17-2.14, p=0.003). In diabetic patients there was significantly increased risk of death in those who had inappropriate therapy (HR = 4.17, 95% CI: 1.52-11.40, p= 0.005) and appropriate therapy (HR = 2.49, 95% CI: 1.06-5.87, p= 0.037) compared to those who did not.
Conclusions—Innovative high-rate cut-off or delayed ICD programming was associated with a reduction in inappropriate therapy in patients with and without diabetes. Diabetes was associated with lower risk of inappropriate therapy but higher risk of appropriate therapy. Appropriate and inappropriate ICD therapy was associated with increased mortality in diabetic patients.
Clinical Trial Registration Information—www.ClinicalTrials.gov. Identifier: NCT00947310.
- Received March 7, 2013.
- Revision received June 10, 2013.
- Accepted June 14, 2013.