Table 4. Additional Subgroup Analyses.

Sugroup Analysis	RR (95% CI)
Country
United States, 13 studies	1.95 (1.28–2.97)*
Canada/Europe, 4 studies	2.25 (1.61–3.14)*
Study Design
High Quality, 3 studies	3.22 (1.32–7.85)*
Study Designed To Assess the Influence of Compensation
Dichotomous Data, 2 studies	1.74 (0.56–5.38)
Continuous Data, 4 studies	−8.05 (−11.08−5.03)*

^*Demonstrates the negative influence of Workers’ Compensation.