Survival and prognostic factors in hypertrophic cardiomyopathy: a meta-analysis

Abstract

Hypertrophic cardiomyopathy (HCM) is a clinically and genetically heterogeneous disorder but data on survival rates are still conflicting and have not so far been quantitatively reviewed. The aim of this study is to conduct a meta-analysis of cohort studies to assess pooled survival rates and prognostic factors for survival in patients with HCM. Nineteen studies were included representing 12,146 HCM patients. The pooled 1-, 3-, 5- and 10-year survival rates were 98.0%, 94.3%, 82.2% and 75.0%, respectively. Among patients with HCM, age, NYHA functional class, family history of sudden death (FHSD), syncope, atrial fibrillation, non-sustained ventricular tachycardia (nsVT), maximum left ventricular wall thickness and obstruction were significant prognostic factors for cardiovascular death. For sudden cardiac death, FHSD, nsVT, and obstruction showed significant predictive values. Moreover, estimation of population attributable risk (PAR) suggested that nsVT was the strongest predictor for cardiovascular death (13.02%, 95% CI 3.60-25.91%), while left ventricular outflow tract obstruction/mid-ventricular obstruction (LVO/MVO) was the strongest predictor for all-cause death and sudden cardiac death (10.09%, 95% CI 4.72-20.42% and 16.44%, 95% CI 7.45-31.55%, respectively). These risk factors may thus be useful for identifying HCM patients who might benefit from early diagnosis and therapeutic interventions.

Figure 1

Flow diagram showing the search strategies used to identify publications for inclusion in the study.

Figure 2

Pooled survival rate of recruited studies. The vertical lines represent 95% confidence intervals.

Figure 3

Begg’s funnel plot to assess the degree of publication bias. Circles in black color represent the six original studies included in the meta-analysis. Eggers test for family history of sudden cardiac death was not significant (p = 0.095). HR: hazard ratio. *We endeavored to conduct a comprehensive analysis, nevertheless, none of these variables were studied by all selected articles, therefore we have selected and focused on FH, which has been reported consistently among these studies, 6 studies showed follow-up data for FH.

Figure 4

Forest plots showing the prognostic value of NYHA and MLVWT, represented by the pooled hazard ratio (HR) in HCM. The diamonds represent the combined HRs for each of the prognostic factors. (A) NYHA class III/IV is the strongest prognostic factor for all-cause death (HR = 1.96; 95% CI (1.58, 2.43)); (B) NYHA class III/IV is the most important risk factor for cardiovascular death (HR = 2.54; 95% CI (2.10, 3.07)); (C) MLVWT is the most important risk factor for sudden cardiac death (HR = 3.17; 95% CI (1.64, 6.13)).