This was a cross-sectional prospective study. We performed a multivariate statistical analysis of the neurological signs and symptoms of patients infected with human T cell lymphotropic virus type 1 (HTLV-1) in an attempt to separate them into distinct groups and identify clinical-neurological manifestations that could differentiate the various profiles. The study was performed in the city of Belém (state of Pará), located in the Amazon region of Brazil, from 2014 to 2016. We determined muscle strength and tone, reflexes, sensations, sphincter function, gait, and the Expanded Disability Status Scale score among individuals with HTLV-I. We then used exploratory statistical methods in an attempt to find different profiles and establish distinct groups. We analyzed 60 patients with HTLV-1. The filtering of the data, performed with mixed PCA, gave rise to a streamlined database with the most informative data and suggested the formation of three statistically distinct groups: asymptomatic carriers (AC), mono/oligosymptomatic (MOS), and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSPd), AC and MOS (p = 0.002), AC and HAM/TSPd (p < 0.001), and HAM/TSPd and MOS (p = 0.001). The subsequent cluster analysis confirmed the formation of three clusters. The classification and regression tree demonstrated that altered gait was the most important variable for the classification of an individual with HAM/TSPd and that, in the absence of this impairment, hyperreflexia characterized MOS. The present study was able to separate patients infected by HTLV-1 into three clinical groups (AC, HAM/TSPd, and MOS) and identify clinical manifestations that could differentiate the various patient groups.
Keywords: Diagnoses and examinations; HAM/TSP; HTLV-I; HTLV-I-associated myelopathy; HTLV-I-associated myelopathy-tropical spastic paraparesis.