Greater symptom duration predicts response to immunomodulatory therapy in dilated cardiomyopathy

Background: Persistent inflammation contributes to cardiac dysfunction in chronic dilated cardiomyopathy (DCM). Trials of immunomodulatory therapy for DCM have been limited by small sample size and yielded conflicting results. We hypothesized that clinical response to immunomodulation would be dependent on symptom duration. Pooled immunomodulatory trial data was used to test this hypothesis. Methods: Data from 130 subjects in 3 randomized, placebo-controlled trials of immunomodulatory therapy in DCM were combined and prospectively analyzed to evaluate change in left ventricular ejection fraction (LV-EF) at 6 and 12 months after randomization by Wilcoxon Rank-Sum test. Logistic regression analysis evaluated correlations between age, gender, symptom duration and change in LV-EF. Results: Patients ≥ 6 months of symptoms before immunomodulatory therapy had a greater increase in LV-EF at 6 and 12 months than those receiving placebo (14.4% vs. 4.4%, p < 0.001 and 19.5% vs. 5.6%, p < 0.001, respectively). Patients with < 6 months of symptoms had a similar increase in LV-EF compared to subjects treated with placebo (14.3% vs. 13.3%, p = 0.84 and 14.8% vs. 15.2%, p = 0.74, respectively). Older age and male gender were not associated with LV-EF change. Conclusion: Immunomodulatory therapy is associated with improved LV-EF in DCM patients with ≥ 6 or more months of symptom duration.