Lindgren MP, et al. - Researchers investigated the heritability of heart failure (HF) in this nationwide adoption study. They found that, the presence of HF in a biological parent conferred increased risk for developing HF in the adoptees and clinicians should consider this while dealing with such cases. Heritability (h²) of HF per Falconer regression was estimated to be 26%. The estimated heritability was 34% if cardiomyopathies were excluded. The importance of genetic factors in HF pathogenesis was indicated by the increased heritability of HF.

Methods

• Researchers calculated risks of HF in adoptees in this case-control study and cohort study design using logistic regression.
• Participants included adoptees who were born in Sweden between 1942 and 1990 and were linked to their adoptive parents and biological parents.
• By linking the Swedish Multi-Generation Register to the Swedish Patient Register, they obtained information on hospital inpatient and outpatient admissions and they also linked the Swedish Multi-Generation Register to the Swedish Cause of Death Register for the period 1964 through 2015.
• Using both Falconer regression and tetrachoric correlation, they determined heritability (h² with a standard error) for HF.
• From July 2017 to April 2018, they completed data analysis.
• Exposures included heart failure in biological parents and/or adoptive parents.
• Main outcomes and measures included heritability; risk of HF, expressed as odds ratios.

Results

• This study included 21,643 adoptees (of whom 10,626 [49.1%] were female), as well as 35,016 adoptive parents (14,872 [42.5%] female) and 43,286 biological parents (21,643 [50.0%] female).
• The identified cases of HF were 194 in adoptees, 3,972 in adoptive parents, and 3,657 in biological parents.
• Relative to those without an affected biological parent, the cohort study odds ratio (OR) for heart failure was 1.45 in adoptees (95% CI, 1.04-2.03) for biological parents with HF.
• This OR was 1.58 (95% CI, 1.03-2.42) with the exclusion of cardiomyopathies.
• They found that the corresponding OR related to an affected adoptive parent were nonsignificant, both with cardiomyopathies included (OR, 0.83 [95% CI, 0.57-1.20]) and with cardiomyopathies excluded (OR, 0.79 [95% CI, 0.49-1.29]).
• According to results, the estimated heritability of HF per Falconer regression (h²) was 26% (SE, 14%).
• The heritability using Falconer regression was 34% (SE, 18%), when cardiomyopathies were excluded.