Polyneuropathy associated with monoclonal gammopathy of undetermined significance (MGUS-PNP) has a chronic and slowly progressive course but can lead to significant disability and reduced quality of life (QoL). The aim of this study was to analyze QoL in MGUS-PNP patients and to determine its predictors. Our study included 51 patients diagnosed with MGUS-PNP (23.5% with IgM, 66.7% IgG or IgA, 7.8% undetermined paraprotein, 2.0% light chains). QoL was assessed using the SF-36 questionnaire. The Medical Research Council Sum Score (MRC-SS), INCAT disability and sensory scores, ataxia score, Krupp's Fatigue Severity Scale and Beck's Depression Inventory were also used. Total SF-36 score was 50.0 ± 21.4 and no difference was observed between IgM and IgG/IgA MGUS-PNP. Physical composite score was worse than mental (44.4 ± 21.4 vs. 54.5 ± 20.9). Following factors showed correlation with SF-36 total score in univariate analysis: INCAT disability score, MRC-SS, INCAT sensory score, level of ataxia, fatigue and depression (p < 0.01). Significant predictors of worse SF-36 total score in our MGUS-PNP patients were depression (β = - 0.46, p < 0.01), fatigue (β = - 0.32, p < 0.01) and INCAT disability score (β = - 0.27, p < 0.01). QoL in MGUS-PNP is equally affected in patients with different types of paraprotein. MGUS-PNP patients with more severe functional disability, fatigue and depression need special attention of clinicians since they could be at higher risk to have worse QoL. This should be taken into account when treating subjects with MGUS-PNP.
Keywords: Depression; Disability; Fatigue; Monoclonal gammopathy of undetermined significance; Polyneuropathy; Quality of life.