Short- and Long-Term Outcomes of Obstructive and Non-Obstructive Hypertrophic Cardiomyopathy: A Systematic Review and Meta-Analysis.

Background: Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiac condition, but the risk factors and outcomes of patients with obstructive (HOCM) and non-obstructive hypertrophic cardiomyopathy (NOCM) remain unclear. This systematic review and meta-analysis was conducted to investigate the risk ratio (RR), incidence, and risk factors of all-cause and HCM-specific mortality.

Methods: This PRISMA-adherent systematic review involved a systematic search of PubMed, SCOPUS, and Embase for studies published from 1 January 2001 to 31 August 2023 that reported outcomes of patients with HOCM and NOCM. Random effects meta-analyses and meta-regressions were used for primary analysis.

Results: Sixty-one observational studies with 52,020 participants were included. All-cause, HCM-related, and heart failure-related mortality had no difference in HOCM vs NOCM patients (RR 0.85, 95% CI 0.58-1.25), (RR 0.95, 95% CI 0.68-1.32), and (RR 0.95, 95% CI 0.58-1.58), respectively. Sudden cardiac death (SCD) was significantly higher in HOCM vs NOCM patients (RR 1.69, 95% CI 1.19-2.42). Incidence of all-cause mortality (NOCM 95.47, 95% CI 63.96-140.18 vs HOCM 65.75, 95% CI 48.04-89.37) per 1,000 observations, HCM-related mortality (NOCM 59.72, 95% CI 41.91-84.42 vs HOCM 55.51, 95% CI 39.42-77.64), and SCD (NOCM 32.17, 95% CI 22.42-45.96 vs HOCM: 25.39 95% CI 15.24-42.01) were higher in NOCM patients, while heart failure-related mortality (HOCM 55.51, 95% CI 39.42-77.64 vs NOCM 30.04, 95% CI 14.78-60.11) was higher in HOCM patients.

Conclusions: The RR of SCD was significantly higher in HOCM vs NOCM patients. All-cause mortality, HCM-related mortality, and SCD were of higher incidence in NOCM patients. Only heart failure-related mortality was higher in HOCM patients.