Health state utility values in people living with HTLV-1 and in patients with HAM/TSP: The impact of a neglected disease on the quality of life

Abstract

Background: HTLV-1 is a neglected sexually transmitted infection despite being the cause of disabling neurological disease HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). There is no treatment for this infection and public health policies are essential to reduce its transmission. However, there are no data to support adequate cost-effective analysis in this field. The aim of this study was to obtain health state utility values for individuals with HAM/TSP and HTLV-1 asymptomatic carriers (AC). The impact of both states on quality of life (QoL) is described and compared to other diseases.

Methods: A cross-sectional observational study of 141 individuals infected with HTLV-1 (79 with HAM/TSP and 62 AC) from three Brazilian states (Rio de Janeiro, São Paulo and Alagoas) and from the United Kingdom. Participants completed a validated general health questionnaire (EQ-5D, Euroqol) from which country specific health state utility values are generated. Clinical and epidemiological data were collated.

Principal findings: Health state utility value for HAM/TSP was 0.2991. QoL for 130 reported clinical conditions ranges from 0.35 to 0.847. 12% reported their quality of life as worse as death. Low QoL was associated with severity rather than duration of disease with a moderate inverse correlation between QoL and Osame's Motor Disability Score (-0.4933) Patients who are wheelchair dependent had lowest QoL whilst those still walking unaided had the highest. AC also reported impaired QoL (0.7121) compared to general population.

Conclusion: HTLV-1 and its associated neurological disease has a marked impact on QoL. This study provides robust data to support the development of cost-utility analysis of interventions for HTLV-1.

Fig 1. Percentage of individuals reporting some problems in each domain according to clinical status and compared with general population.

A) UK (general population data according to Sullivan et al 2011 and Szende et al 2014); B) Brazil (general population data according to Santos et al 2016).

Fig 2. Comparison of EQ-5D Index and VAS Score according to clinical status.

Fig 3. Factors impacting the quality of life in HAM/TSP individuals.

A) EQ-5D Index according to the need of support to walk; B) Correlation between OMDS and EQ-5D Index; C) Correlation between EQ-5D Index and age in HAM/TSP individuals.

Fig 4. EQ-5D Index in people living with HTLV-1 compared with selected other diseases.

A) Brazil, B) UK.