Cardiac amyloidosis increasingly common in US

New research suggests the incidence of cardiac amyloidosis in the U.S. is trending up, bringing with it high rates of morbidity and mortality.

Scientists have long assumed the instance of cardiac amyloidosis—the deposition and buildup of immunoglobulin light chains (AL) or transthyretin (ATTR) in heart tissue—is on the rise, Brett W. Sperry, MD, and colleagues wrote in the American Journal of Cardiology. Recent years have seen a rise in awareness of the disease, more novel treatment options and improved noninvasive diagnostic imaging modalities, but the hospitalization trends for amyloidosis remain unclear, especially for AL type.

Sperry, of the Mid America Heart Institute at Saint Luke’s Hospital and University of Missouri-Kansas City in Kansas City, Mo., combed National Inpatient Sample data with his team to identify 156,914 patients hospitalized with amyloidosis between 2005 and 2014. Patients were on average 70 years old and more often white men, and 34.7% of the pool presented with concomitant heart failure.

The researchers noted the overall number of hospital admissions in patients with amyloidosis more than doubled during the study period—from 9,296 in 2005 to 21,740 in 2014. During the peak in 2014, 62 of every 100,000 hospital admissions was related to amyloidosis.

“The explanation for the more than doubling of the rate of hospitalization in those with amyloidosis is likely multifaceted,” Sperry et al. wrote in AJC. “One possibility is that the incidence and prevalence of amyloidosis are increasing due to a growing awareness of the disease. Alternatively, the aging of the population may contribute to these observed trends.”

Over time, patients admitted with amyloidosis tended to be older and have more medical comorbidities, the authors said. They also had longer lengths of stay than those without the disease (7.5 vs. 6.2 days), were less likely to be discharged home (43.6% vs. 48.7%) and were more likely to die while hospitalized (7.4% vs. 4.9%). Patients with concomitant heart failure fared worse in terms of mortality, too.

Sperry and colleagues said it’s impossible to differentiate between AL and ATTR amyloidosis in the NIS, but said it seems likely that ATTR is contributing more to the rise in amyloidosis given the increase in older and black patients over time with a decrease in concomitant multiple myeloma. AL amyloidosis diagnoses, on the other hand, have remained relatively stable for the past seven decades while prevalence has increased, likely because older patients are living longer.

Though their study was inherently limited by the possibility of NIS inaccuracies and human error, the authors said their study was able to shed light on some of the lesser-known characteristics of amyloidosis in the U.S.

“Given the increasing prevalence of hospitalizations in patients with amyloidosis, enhanced diagnostic and treatment options have the potential to improve care for a growing population of patients,” they wrote.