Prevalence of and factors associated with unmanageable pain levels in people with knee or hip osteoarthritis: a cross-sectional population-based study

Abstract Background Pain due to knee or hip osteoarthritis (HKOA) is the most common symptom for seeking health care given its interference on daily activities, social and occupational participation. The goal of this study is to estimate the prevalence of unmanageable pain levels (UPL) among people with hip and/or knee osteoarthritis (HKOA), characterize this population and identify factors associated with UPL, and compare therapeutic strategies used by people with UPL versus manageable pain levels (MPL). Methods We analyzed a representative sample of 1081 participants with a validated diagnosis of HKOA, from the population-based study EpiReumaPt. Sociodemographic, lifestyle and health-related data were collected in a structured interview. Pain intensity (NPRS) data were collected in a medical appointment. UPL was defined as a mean pain intensity in the previous week of ≥ 5 points on 11-point numeric pain rating scale. Intake of regular medication for pain relief (last month), physiotherapy and surgery were considered as therapies for pain management. The factors associated with UPL were analyzed with logistic regression (p < 0.05, 95%CI). To assess the effects of unmanageable pain levels in the HOOS/KOOS activities of daily living and quality of life subscales and in the presence of anxiety and depression symptoms, linear and logistic regression were used. All analysis were weighted. Results The estimated prevalence of UPL among people with HKOA was 68.8%. UPL was associated with being female (odds ratio (OR) = 2.36, p < 0.01), being overweight (OR = 1.84, p = 0.035) or obese (OR = 2.26, p = 0.006), and having multimorbidity (OR = 2.08, p = 0.002). People with UPL reported worse performance in activities of daily living and lower quality of life (β=-21.28, p < 0.001 and β=–21.19, p < 0.001, respectively) than people with MPL. People with UPL consumed more NSAIDs (22.0%, p = 0.003), opioids (4.8%, p = 0.008), paracetamol (2.7%, p = 0.033), and overall analgesics (7.3%, p = 0.013) than people with MPL. A higher proportion of people with UPL underwent physiotherapy (17.5%, p = 0.002) than people with MPL. Conclusion These results indicate that most people with HKOA have poor control of pain, highlighting the need for further research and implementation of effective interventions.