OBJECTIVES: Transthyretin Familial Amyloid Polyneuropathy (TTR-FAP) is a rare, progressive, debilitating and life-threatening neurodegenerative disease. The purpose of this study was to assess the health-related quality of life (HRQoL) impairment of TTR-FAP disease versus Portuguese general population. Literature on TTR-FAP patients HRQoL is scarce at worldwide level and no evidence on HRQoL index score for Portugal has been published.

METHODS: HRQoL was measured using the validated EuroQoL five dimensions three levels (EQ5D-3L) questionnaire being the index score (utility) calculated trough the Portuguese scoring algorithm. The Portuguese general population reference set (n = 1500) was pooled with TTR-FAP patients specific data (n = 1091) extracted from Transthyretin Amyloidosis Outcomes Survey (THAOS) registry. Demographic variables include gender and age. Ordinary Least Squares (OLS) regression for utility was set to test if being asymptomatic carrier caused HRQoL impairment, conditional in other individual characteristics. Generalized linear models (GLM) were specified for disutility in order to disentangle and quantify TTR-FAP effect on HRQoL versus Portuguese general population. Akaike information criteria (AIC) were used to select the most adequate statistical model.

RESULTS: In a scale from -0.50 to 1.00 the average utility score was 0.76 (0.25) for general population, 0.823 (0.24) for TTR-FAP asymptomatic carriers (n=525) and 0.50(0.37) for symptomatic TTR-FAP patients (n=566). OLS including independent gender and age variables, indicated no significant statistical effect on utility for being a TTR-FAP asymptomatic carrier (p-value 0.54) versus general population. GLM (AIC -0.58) detected a significant statistical effect for gender, age and being symptomatic TTR-FAP patient. Average women aged 44 years and symptomatic TTR-FAP patient, has a 40% impairment on utility versus women aged 44 years from general population.  CONCLUSIONS: The preference-based utility measures used in this study adequately disentangle TTR-FAP disease impact on patient’s health-related quality of life. This study allows us to quantify the large HRQoL effect that TTR-FAP induces.