Description and Prognosis of Patients with Recovered Dilated Cardiomyopathy: A Retrospective Cohort Study

Background: With the recent advances in the treatment of heart failure (HF), it is intriguing that a very small number of patients with dilated cardiomyopathy (DCM) have been observed as being fully recovered. However, knowledge of the progression and prognosis of patients with recovered DCM remains sparse. Herein, we conducted this study to investigate the clinical characteristics and prognosis of patients with recovered DCM. Methods: Consecutive patients with recovered DCM referred to our hospital between March 2009 and May 2021 were included. The recovered DCM patients were categorized into relapse and non-relapse groups. The primary endpoint was all-cause death, and the secondary endpoint was HF re-hospitalization during follow-up. Multivariate analyses were performed to identify predictors of relapse among recovered DCM patients. Kaplan-Meier analyses were used to assess the prognostic significance of relapse. Results: A comparatively large cohort of 122 recovered DCM patients from 10,029 DCM patients was analyzed. During a median follow-up duration of 53.5 months, the relapse rate among recovered DCM patients was 15.6% (19/122). Age (odds ratio, OR 1.079, 95% confidence interval, CI: 1.014-1.148; p = 0.017), systolic blood pressure (SBP) at diagnosis (OR 0.948, 95% CI: 0.908-0.990; p = 0.015) and changes in left ventricular ejection fraction from diagnosis to recovery (Delta LVEF) (OR 0.898, 95% CI: 0.825-0.978; p = 0.013) were identified as predictors of relapse. Furthermore, among 122 patients, 5 (4.1%) experienced death, and 12 (9.8%) underwent HF re-hospitalization. Four deaths occurred in the relapse group, with one in the non-relapse group. All deaths were attributed to cardiovascular events. The long-term prognosis of the relapse group was significantly worse compared to the non-relapse group by Kaplan-Meier analysis (p < 0.001 based on the log-rank test). Multivariate analyses significantly associated relapse with all-cause mortality in recovered DCM patients (hazard ratio, HR 7.738, 95% CI: 1.892-31.636; p = 0.004). Conclusions: Recovered DCM patients are at risk of relapse. Older age, lower SBP, and smaller Delta LVEF were independently associated with relapse in recovered DCM patients. Relapse after recovery was related to an unfavorable long-term prognosis.