Background It is intuitive that disablement due to illness should be reflected in illness severity. When illness measurement is based on subjective report only, without objective validation, the reliability of symptom report is crucial and requires critical evaluation. Societal costs for fibromyalgia (FM) are high with disability rates up to 30% reported in the developed world.
Objectives To examine clinical characteristics of FM patients currently employed or receiving disability payments.
Methods Of 246 participants in a tertiary care cohort study of FM patients, 90 were employed, 77 receiving disability payments. Demographic and disease severity measures included: pain visual analog scale (VAS), patient global assessment (PGA), Fibromyalgia Impact Questionnaire (FIQ), Health Assessment Questionnaire (HAQ), McGill Pain Questionnaire (MPQ), Pain Disability Index (PDI), Pain Catastrophizing Scale (PCS), anxiety and depression by Arthritis Impact Measurement Scale (AIMS). Between-group differences in discrete and continuous variables were assessed for statistical significance with the Chi-Square test and the independent-samples t-test, respectively. Linear regression was used to assess between-group differences in disease activity while adjusting for potential confounders.
Results The prevalence of disablement was 30.8%. Disabled patients were significantly older (49.1 vs. 45.9; P=0.020), more likely to smoke cigarettes (33.8% vs. 15.6%; P=0.006) or use marijuana (13.0% vs. 3.3%; P=0.020). No significant differences were observed in pain duration (10.7 years) and gender (female: 91.0%). Prior/current occupation type differed significantly between groups: disabled patients were more likely previously employed in manual professions or service industry, with employed patients occupied in education/clerical/health fields (P=0.001). Significant between-group differences were observed for management strategies: disabled patients used a greater count of medications (P=0.001), more opioids (P=0.001), antidepressants (P=0.032), tranquilizers (P<0.001), and cannabinoids (P=0.053), and participated less in exercise activity (P=0.009). Those disabled demonstrated more allodynia (P=0.027) and pain related behaviour (P=0.002). Except for depression and anxiety, all other parameters were significantly higher in the disabled group: pain VAS (P<0.001), PGA (P<0.001), FIQ (P<0.001), HAQ (P<0.001), MPQ (P<.0001), PCS (P=0.005) and PDI (P<0.001). All associations remained significant except for HAQ, MPQ, and PCS when adjusted for age and education.
Conclusions The results of this analysis suggest that a significant proportion of FM patients are unemployed due to disability. The subjective report of symptom severity for those disabled may be explained by true disease severity, negative impact of medications, or patient perception of illness and suffering. Alternately, justification for ongoing disablement may be the driver for augmentation of subjective illness report. As all measurements in FM are subjective, disabled patients may be an important confounder for understanding outcome in FM.
Disclosure of Interest : M.-A. Fitzcharles Speakers bureau: Lilly, Pfizer, Purdue, Valeant, E. Rampakakis: None declared, P. Ste-Marie: None declared, J. Sampalis: None declared, Y. Shir Consultant for: McKesson Canada Corporation, Palladin Inc. Canada