The prevalence of transthyretin amyloid cardiomyopathy (ATTR-CM) in women appears to be higher than previously thought, according to a recently published study in The American Journal of Cardiology.
For decades, ATTR-CM has been thought to affect primarily men. But recent studies have shown that the prevalence in women could be higher than previously thought. As early diagnosis and treatment initiation is crucial for therapeutic success, there are concerns that women could be underdiagnosed.
What is ATTR-CM?
Transthyretin amyloidosis cardiomyopathy (ATTR-CM) is a rare progressive disease of the heart muscle that leads to congestive heart failure. It occurs when the transthyretin protein produced by the liver is unstable. Symptoms include fatigue; shortness of breath; irregular heart rate or palpitations; swelling of the legs, ankles and stomach; brain fog; wheezing; and dizziness. It often goes underdiagnosed because of a lack of awareness and knowledge of the disease. There is currently no cure for ATTR-CM.
“Intriguingly, ATTR-CA [transthyretin cardiac amyloidosis] repeatedly has been reported as a disease of male predominance, but this observation has been questioned by conflicting studies and concerns of potential underdiagnosis (or delayed diagnosis until later clinical courses) amongst women,” the authors said.
Read more about ATTR-CM testing and diagnosis
The study aimed to compare the sex distribution and phenotypic characteristics of two groups of patients diagnosed with ATTR-CM.
Patients in the first group participated in the screening for cardiac amyloidosis with nuclear Imaging in minority populations study (SCAN-MP), which recruited African American and Latino patients with cardiac failure. The second group included patients referred to a specialized center because they were suspected of having ATTR-CM.
The key difference between both groups was that the first was an active screening program, while the other depended on referrals based on clinical suspicion. The hypothesis was that women would be underrepresented in the second group.
The SCAN-MP study identified 36 patients with ATTR-CM and more than 300 referral programs. There were significant differences in the proportion of women in both groups (31% vs. 13%). According to echocardiogram parameters, women diagnosed through the SCAN-MP study had a less advanced disease than those in the referral program.
Previous studies have shown that eliminating patient selection bias based on sex could increase the diagnosis rate in women, and the results of this study strongly support these findings.
“One proposed explanation for the observed sex imbalance is that women are underdiagnosed,” the authors said. “This hypothesis is credible based on our data in that the prevalence of women with ATTR-CA in our cohort, especially ATTRwt-CA [wild-type ATTR-CA], is noticeably higher with an active ascertainment approach than the referral cohort, the latter of which reflects the vast majority of prior reports in the literature.”