Background This retrospective longitudinal study was performed to determine whether
tafamidis treatment leads to improvements in commonly used blood data for
transthyretin familial amyloid polyneuropathy (TTR-FAP). Methods Commonly used blood data (complete blood count [including a haemogram], total
protein,
albumin, blood
urea nitrogen,
creatinine,
aspartate aminotransferase,
alanine aminotransferase,
alkaline phosphatase,
lactate dehydrogenase, γ-
glutamyl transpeptidase, total
bilirubin [T-Bil],
creatine kinase,
choline esterase,
high-density lipoprotein cholesterol,
low-density lipoprotein cholesterol, estimated glomerular filtration rate [eGFR],
serum amyloid A protein, TTR, haemoglobin A1c, free
triiodothyronine [FT3] and free
thyroxine [FT4]) were investigated in 33 TTR-FAP patients. These values included longitudinal data at three time points: six months before or after
tafamidis treatment and one year after
tafamidis treatment. Longitudinal changes in each blood item were examined using a linear mixed model, adjusting for age at starting
tafamidis, sex, TTR-FAP stage and value before
tafamidis treatment. Results Our results show elevated TTR concentrations after
tafamidis treatment. In contrast, haemoglobin, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration, mean platelet volume, platelet distribution width, T-Bil, eGFR, FT3 and FT4, gradually decreased through a reference range. There were no characteristic observations in any other items. TTR binds to
thyroid hormone; therefore, FT3 and FT4 decreased in inverse proportion to increased TTR concentrations. Conclusion Unfortunately, progression to anaemia may occur regardless of
tafamidis treatment. Because anaemia is sometimes present in TTR-FAP, attention should be paid to longitudinal changes in commonly used blood data, irrespective of
tafamidis treatment.