Depression and trait-anxiety mediate the influence of clinical pain on health-related quality of life in fibromyalgia

Highlights

• Clinical and psychological factors play a relevant role in the decrease of Health Related Quality of Life in Fibromyalgia Syndrome patients.

• Fibromyalgia Syndrome pain and related functional disability may increase depression and anxiety, aggravating the primary symptoms of Fibromyalgia Syndrome and indirectly increasing the negative influence of pain on Health Related Quality of Life.

• It is necessary to evaluate and treat aversive emotional states in Fibromyalgia Syndrome.

Abstract

Background

Fibromyalgia syndrome (FMS) is a chronic pain condition associated with a substantial decrease in health-related quality of life (HRQoL). This study investigated the relationships of HRQoL with clinical parameters of FMS (pain, insomnia and fatigue) and affective variables (depression and anxiety).

Methods

Women with FMS (n=145) and healthy women (n=94) completed the Short-Form Health Survey (SF-36) to evaluate HRQoL, and self-report questionnaires pertaining to clinical pain, symptoms of anxiety and depression, fatigue and insomnia. Patterns of associations were assessed by correlation, multiple linear regression, and mediation analyses.

Results

FMS patients showed lower scores on all SF-36 scales than healthy individuals. Clinical and emotional factors were inversely associated with SF-36 scores. Although depression was the strongest predictor of global HRQoL (explaining 36% of its variance), clinical pain and fatigue were the main predictors of physical components of HRQoL; depression and trait-anxiety were the main predictors of mental HRQoL components. Results of mediation analysis showed that depression, trait-anxiety and fatigue mediated the effect of clinical pain on HRQoL. Additionally, depression, trait-anxiety and fatigue mutually influenced each other, increasing their negative effects on the different areas of HRQoL.

Limitations

Among all emotional factors, only anxiety and depression were considered.

Conclusions

Our results suggest that FMS pain and related functional disability may increase depression and anxiety, in turn aggravating the primary symptoms of FMS and indirectly increasing the negative influence of pain on HRQoL. These results showed the need to evaluate and treat negative affective states in FMS.

Introduction

Fibromyalgia syndrome (FMS) is a chronic disorder characterized by symptoms such as widespread musculoskeletal pain, fatigue, sleep disturbance, cognitive deficits, depression, and anxiety. Its prevalence is estimated at 2 to 4% in the general population, with women being predominantly affected Current etiological models assume that sensitization of central nociceptive pathways is the main origin of pain (Gracely et al. 2002).

FMS involves psychosocial impairments and a severe reduction in quality of life (Arnold, 2008). Within a global, inclusive and multi-disciplinary approach to health, health-related quality of life (HRQoL) is defined as an individual's own evaluation of his or her health and level of adaptive functioning in day-to-day activities, including physical, psychological and social functions (Schwartzmann, 2003). HRQoL has become an essential measure for comprehensive and integrated care of patients with chronic diseases. As a measure evaluating the repercussions and impact of illness on daily life, it provides additional relevant information beyond simply diagnosis of the disease (Minayo et al. 2000). One of the most widely used instruments to measure HRQoL is the Short-Form Health Survey (Ware and Sherbourne, 1992), which allows for the evaluation of different facets and dimensions of the construct (Turkyilmaz et al. 2012; Rodríguez and Campos, 2013).

In a number of studies, FMS patients displayed low HRQoL levels, regardless of the presence of comorbidities (Perrot et al. 2011; Andréll et al. 2014; Jeong-Won et al. 2017). FMS markedly reduces perceived functioning in physical, psychological, and social spheres, and has a negative impact on personal relationships, parenting, work, activities of daily life, mental health and social relationships (Karper, 2016; Freitas et al. 2017; Neuprez and Crielaard, 2017). These adaptive limitations may in turn lead to functional, professional career development-related and economic problems (Cabo-Meseguer et al. 2017; Marques et al. 2017).

The central feature of FMS is pain. Pain has a negative impact on HRQoL and also increases stress and negative affect levels. Current evidence from surveys (Choy et al. 2010), SF-36 assessments (Turkyilmaz et al. 2012; Rodríguez and Campos, 2013) and the 12-item Short-Form Health Survey (Martins et al. 2011) suggest that lower HRQoL in FMS is the result of high levels of pain (intensity and chronicity) and difficulties in its management. However, the affective symptoms that characterize FMS (Wolfe et al. 2010) may also be relevant to HRQoL impairment. Negative emotional states can increase symptom perception and disability by different mechanisms, such as increased interoceptive attention, and somatosensory and symptom amplification, and interpretation thereof in more negative terms (Watson and Pennebaker, 1989). As such, a vicious circle may be established, wherein pain increases the degree of depression-anxiety and the latter in turn increases the perception of pain, and thus decreases HRQoL (Perrot et al. 2011). Furthermore, autonomic nervous system (ANS) activation, linked to anxiety and depression, may generate somatic correlates leading to heightened symptoms perception. Confirming this hypothesis, high anxiety and depression levels, and lower HRQoL, are seen in FMS patients (Perrot et al. 2011; Turkyilmaz et al. 2012).

Fatigue (Faro et al. 2014) and sleeping difficulties such as insomnia, awakening unrefreshed and daytime somnolence (Wagner et al. 2012) are other prevalent symptoms of patient surveys of the impact of fibromyalgia. Some studies have revealed associations between sleep problems and HRQoL in FMS (D'Aoust et al. 2017). Sleep difficulties increase fatigue and anxiety, thereby decreasing HRQoL (Turkyilmaz et al. 2012). Furthermore, pain can provoke insomnia (Wagner et al. 2012). Sleeping difficulties have been associated with neuroendocrine and immune abnormalities in FMS, suggesting that sleep problems might be both a cause and consequence of the illness (Turkyilmaz et al. 2012).

Depressive and anxiety disorders are highly prevalent in FMS (Wolfe et al. 1990; Arnold, 2008) and a high proportion of patients take antidepressants and anxiolytic medication (Montoro et al. 2015), as well as analgesic drugs. However, the effects of standard FMS medications on HRQoL have not yet been comprehensively studied.

In this context, the aim of this study was to evaluate the relationships between HRQoL and levels of pain, insomnia, fatigue, depression and anxiety in FMS. To this end, correlational, multiple regression and mediation analyses were performed. Specifically, a model was devised to test the following predictions: (1) depression, anxiety, fatigue and insomnia mediate the influence of pain on HRQoL; (2) pain mediates the influence of depression, anxiety, fatigue and insomnia on HRQoL; and (3) depression, anxiety, fatigue and insomnia influence each other, leading to an enhancement of their negative effects on HRQoL. Furthermore, we also analyzed the influence of comorbid emotional disorders (depression and anxiety) and medication use on the HRQoL of FMS patients. Before conducting the described analyses, and to replicate the results of previous studies, we explored differences in HRQoL between FMS patients and a group of healthy participants. Because age, Body Mass Index (BMI) and education may affect HRQL (Bosch et al. 2002; Kim et al. 2012; Schochat and Beckmann, 2003), these variables were used as covariates.