Predicting low back pain-related absenteeism in the Spanish general working population.

OBJECTIVES

To identify factors associated with an increased risk of low back pain (LBP)-related sick leave and to develop prognostic models for both the likelihood and duration of such leave.

METHODS

A total of 7262 actively working adults were recruited consecutively during their annual check-ups. Seventy-seven variables were assessed, including sociodemographic, clinical, work-related, LBP-related and psychosocial factors. Outcomes included the occurrence of LBP-related sick leave and the number of days on leave over an 18-month follow-up period. Multivariable prognostic models were developed

RESULTS

During the follow-up, 535 participants (7.4%, 95% CI 6.8 to 8.0) took LBP-related sick leave, of whom 162 were off work for ≥30 days. Predictors of taking sick leave were older age, not being self-employed, a usual LBP episode duration >14 days, higher job insecurity, greater self-expectations of taking sick leave and stronger perceived economic consequences of being on leave. Predictors of longer sick leave (≥ 30 days) were not being self-employed and experiencing LBP while in bed. The models demonstrated good calibration but poor discrimination (C-statistics: 0.607 and 0.604).

CONCLUSION

Predicting LBP-related sick leave and its duration among the general Spanish workforce remains challenging. Psychosocial and economic variables outweigh clinical or biological predictors. Self-employment is the only factor associated with a lower risk of both sick leave and being off work for ≥30 days.

TRIAL REGISTRATION NUMBER: NCT00667316.