Risk factors for long-term sickness absence in patients with high-impact chronic pain – a scoping review and Swedish register-based cohort study

High-impact chronic pain (HICP) affects 8% of individuals worldwide. Beyond its direct consequences, HICP increases the risk of long-term sickness absence (LTSA), leading to income loss and increased societal costs. Prevention is essential and understanding risk factors for LTSA is a critical first step. We conducted a joint scoping review and Swedish register-based cohort study, to first identify and subsequently analyze potential risk factors. A multivariable logistic regression model estimated the association between the risk factors and LTSA, defined as >180 sickness absence days in the third year after specialist healthcare entry. The likelihood ratio chi-square test determined each factor's contribution to model fit. Associations were reported as marginal risk ratios (mRR) with 95% confidence intervals (95% CI), comparing the 75th to the 25th sample percentiles. Of 57 identified risk factors, 34 were analyzed in a sample of 10,552 patients, 25% of whom experienced LTSA. Seven risk factors contributed significantly at a Bonferroni-adjusted alpha level: prior sickness absence, (mRR: 2.53; 95% CI: 2.40-2.66), comorbid neurological disorders (1.60; 1.38-1.81), self-rated work ability (1.42; 1.29-1.58), confidence in recovery (1.21; 1.13-1.30), female sex (1.18; 1.10-1.26), pain duration (1.11; 1.03-1.20), and household income, which showed a complex non-monotonic relationship. In line with previous research, the strongest association was with prior sickness absence. By targeting the aforementioned risk factors, workforce reintegration could be facilitated for individuals with HICP. PERSPECTIVE: Our scoping review and large sample Swedish register-based study identifies and quantifies key risk factors for long-term sickness absence in individuals with high-impact chronic pain, providing a foundation for early identification and targeted rehabilitation, which in the longer perspective could support workforce reintegration and reduce individual suffering and societal costs.