# Pay-for-performance and low back pain with interaction of overwork: findings from the cross-sectional Korean working conditions survey

## TL;DR

This study finds that pay-for-performance systems may increase low back pain in workers, especially when combined with overtime.

## Contribution

The study explores the novel link between pay-for-performance systems and low back pain, particularly in the context of overtime work.

## Key findings

- Pay-for-performance combined with base pay increased low back pain risk compared to base pay alone.
- Overtime work significantly increased low back pain risk, especially when combined with pay-for-performance.
- Adjusting for confounding variables eliminated the statistical significance of pay-for-performance's direct effect on low back pain.

## Abstract

Pay-for-performance (PFP) is a type of incentive system where employees receive monetary rewards for meeting predefined standards. While previous research has investigated the relationship between PFP and health outcomes, the focus has primarily been on mental health. Few studies have explored the impact of PFP on specific physical symptoms like pain.

Data from the Korean Working Conditions Survey (KWCS) was analyzed, encompassing 20,815 subjects with information on PFP and low back pain (LBP). The associations between types of base pay (BP) and PFP with LBP were examined using multivariate logistic regression models, taking into account a directed acyclic graph (DAG). The interaction of overtime work was further explored using stratified logistic regression models and the relative excess risk for interaction.

The odds ratio (OR) for individuals receiving both BP and PFP was statistically significant at 1.19 (95% CI 1.04–1.35) compared to those with BP only. However, when the DAG approach was applied and necessary correction variables were adjusted, the statistical significance indicating a relationship between PFP and LBP vanished. In scenarios without PFP and with overtime work, the OR related to LBP was significant at 1.54 (95% CI 1.35–1.75). With the presence of PFP, the OR increased to 2.02 (95% CI 1.66–2.45).

Pay-for-performance may influence not just psychological symptoms but also LBP in workers, particularly in conjunction with overtime work. The impact of management practices related to overtime work on health outcomes warrants further emphasis in research.