Prevalence of ATTR-CM and Subtypes of Cardiac Amyloidosis
The total number of patient records in the MDV database between January 2010 and September 2018 was 25,333,955, of whom 20,894,625 were aged ≥ 20 years (Fig. 1). Of these, the majority (69.5%) were outpatients only, while 30.4% had ≥ 1 inpatient visit and 4.4% had ≥ 1 inpatient visit only (no outpatient visit). The mean (SD) age of all patients in the database was 57.7 (18.9) years and 46.3% were male. The majority of patients in the database (59.3%) were from hospitals of an intermediate size (200–499 beds), while 29.6% were from hospitals with ≥ 500 beds and 11.1% were from hospitals with ≤ 199 beds.
Over the whole period (January 2010 to September 2018), there were 3992 diagnoses of ATTRwt and 106 diagnoses of ATTRm using the broad definition of ATTR-CM. Using the narrow definition of ATTR-CM, there were 3255 diagnoses of ATTRwt and 67 diagnoses of ATTRm (Fig. 1, Table 1). There were 444 diagnoses of AL amyloidosis.
Table 1 Prevalence of ATTR-CM and subtypes of cardiac amyloidosis The most common diagnosis code for patients with ATTRwt was “amyloidosis,” representing over half of the diagnosed patients, followed by “cardiac amyloidosis” and “secondary amyloidosis.” The most common diagnosis code for patients with ATTRm was “familial amyloidosis,” followed by “cardiac amyloidosis” and “amyloidosis” (Table 1). The number of sites and number of patients in the MDV database increased each year. From 2013, the prevalence of ATTRwt and ATTRm as recorded in the database increased each year, as did the number of sites in the database (Fig. 2).
A total of 1,538,693 patients in the database had a diagnosis of heart failure (Fig. 1). Considering only patients who were also diagnosed with heart failure, there were 1798 (86.1 per million) diagnoses of ATTRwt and 61 (2.9 per million) diagnoses of ATTRm using the broad definition of ATTR-CM. Using the narrow definition of ATTR-CM, there were 1468 (70.3 per million) diagnoses of ATTRwt and 50 (2.4 per million) diagnoses of ATTRm (Table 2). There were 308 (14.7 per million) diagnoses of AL amyloidosis.
Table 2 Prevalence of ATTR-CM and subtypes of cardiac amyloidosis in patients diagnosed with heart failure Demographic Characteristics of Patients with Cardiac Amyloidosis
Under the broad definition, and over the whole period, greater than half (53.7%) of the ATTRwt patients were female (Table 3), while the majority of both the ATTRm patients (61.3%; Table 4) and the AL amyloidosis patients (59.2%; Table 5) were male. ATTRm patients tended to be younger (mean [SD] age, 63.7 [15.2] years) than ATTRwt (68.1 [14.2] years) and AL amyloidosis (68.8 [11.1]) patients. The proportion of the patients aged ≥ 80 years was higher for the ATTRwt patients (23.0%) than for the ATTRm (9.4%) or AL amyloidosis (16.9%) patients. The proportion of patients with ATTRwt tended to increase with age (76.9% of the ATTRwt patients were aged ≥ 60 years), and this trend was observed for every ATTR-CM diagnosis code.
Table 3 Demographic characteristics of the ATTRwt patients (broad definition) Table 4 Demographic characteristics of ATTRm patients (broad definition) Table 5 Demographic characteristics of AL amyloidosis patients AL amyloidosis patients were more likely to have ≥ 1 hospital visit (84.2%) than ATTRwt (62.6%) or ATTRm (63.2%) patients. AL amyloidosis patients were also more likely to have their claims data from a larger hospital than ATTRm patients who were, in turn, more likely have their claims data from a larger hospital than ATTRwt patients. However, each group was more likely to be from a larger hospital than the 20,894,625 patients in the whole MDV database, 11.1% of whom were from a hospital with ≤ 199 beds, 59.3% were from a 200- to 499-bed hospital, and 29.6% were from a ≥ 500-bed hospital. Compared with patients in the whole MDV database, each group was also more likely to have died in the hospital (2.7%, 12.8%, 8.5%, and 22.5% for the whole MDV database, ATTRwt, ATTRm, and AL amyloidosis, respectively) and more likely to be from a university hospital (5.9%, 12.8%, 16.0%, and 9.7% for the whole MDV database, ATTRwt, ATTRm, and AL amyloidosis, respectively).
Considering only those patients with a diagnosis of heart failure, demographic characteristics were largely similar to those of all ATTR-CM patients (Table 6). There remained a relatively high proportion of female ATTRwt patients (44.8%, compared with 53.7% of all ATTRwt patients). However, ATTRwt patients with heart failure were more likely to have had ≥ 1 inpatient visit (82.3% compared with 62.6%) or to have died in hospital (21.1% compared with 12.8%).
Table 6 Demographic characteristics of ATTR-CM and subtypes of cardiac amyloidosis patients diagnosed with heart failure (whole period) Diagnostic Modalities in Patients with ATTR-CM (Broad Definition)
The large majority of patients diagnosed with ATTR-CM did not have a record of a tissue biopsy or a scintigram with sodium pyrophosphate. The greater proportion of those who did were inpatients (Table 7). Approximately 9% of all ATTRwt patients (both inpatients and outpatients) had an endomyocardial biopsy or abdominal wall biopsy at any time. Digestive tract biopsy was more common (1011 patients, 25.3%), but it was rare for patients with a digestive tract biopsy to also have an endomyocardial biopsy (59 patients) or abdominal wall biopsy (65 patients), which would be required to optimally confirm a diagnosis of ATTRwt.
Table 7 Diagnostic modalities for ATTR-CM and subtypes of cardiac amyloidosis in inpatients and outpatients (whole period) Diagnostic modalities were largely similar in the subgroup of patients diagnosed with heart failure, with digestive tract biopsy and scintigram with sodium pyrophosphate slightly more common (Table 8).
Table 8 Diagnostic modalities for ATTR-CM and subtypes of cardiac amyloidosis patients diagnosed with heart failure (whole period) Considering only diagnostic modalities within 8 weeks of diagnosis in all patients, 121 (3.0%) ATTRwt patients had an endomyocardial biopsy, 41 (1.0%) had an abdominal wall biopsy, and 407 (10.2%) had a digestive tract biopsy, while 14 (0.4%) had a scintigram. Among the patients with a digestive tract biopsy, endomyocardial biopsy (21 of 407 patients) and abdominal wall biopsy (17 of 407 patients) were rare.