How pain intensity and mental disorders shape chronic pain sick leave and quality of life in the general Spanish population

Chronic pain (CP) is a public health problem with significant consequences for the patient's life. This study aims to analyze the prevalence of sick leave due to CP in Spain and to explore how pain intensity and mental disorders mediate the relationship between sick leave and health-related quality of life (HRQL) in subjects with CP. This study is a secondary analysis from data collected in a cross-sectional study called "Barometro del Dolor" with 7058 participants, representing the Spanish adult population. Sociodemographic information, presence and characteristics of CP, sick leave due to CP, anxiety and depression (HADS) and HRQL (SF-12v2) were collected. The prevalence of sick leave and four serial multiple mediation analyses were conducted. CP prevalence was 25.9% (95%CI 24.8-26.9), while 28.6% (95%CI 26.4-30.8) needed sick leave due to CP in the last year. Sick leave was associated with worse HRQL through the mediating effect of pain intensity and anxiety/depression, showing a non-significant direct effect for the mental component summary of the SF12v2 after accounting for the indirect effects. The direct effects linked CP sick leave to a worse physical component summary, higher pain intensity, anxiety and depression. This study highlights the strong impact of CP on the Spanish workforce providing new insights into hypothesized statistical pathways linking CP sick leave and HRQL through pain intensity and anxiety/depression symptoms.