TABLE V.

Cohort data (N=11,184): Unadjusted and adjusted regression models of reinjury risk, by age and timescale

Characteristic/Model	Calendar quarters			FTE quarters (hours worked/520)
Unadjusted: Age	HR	95% CI	p	HR	95% CI	p
65+ years old (Ref: <65 years old)	0.45	0.31–0.67	<0.001	0.70	0.47–1.03	0.07
Adjusted	HR	95% CI	p a	HR	95% CI	p a
65+ years old (Ref: <65 years old)	0.46	0.31–0.68	<0.001	0.77	0.52–1.15	0.20
Women (Ref: Men)	0.83	0.72–0.95	0.007	0.95	0.82–1.09	0.46
Preferred language (Ref: English)			0.048			0.02
Spanish	1.02	0.86–1.20		0.95	0.80–1.12
Other	0.60	0.39–0.90		0.55	0.36–0.84
Urban-rural residence county (Ref: Large central metropolitan)			0.053			0.005
Large fringe metropolitan	1.07	0.92–1.25		1.17	1.00–1.37
Medium metropolitan	0.98	0.82–1.17		1.02	0.85–1.22
Small metropolitan	0.93	0.76–1.13		0.93	0.76–1.14
Micropolitan	0.84	0.66–1.06		0.80	0.63–1.02
Noncore	0.54	0.32–0.90		0.61	0.36–1.03
Injured body part (Ref: Spine/neck)			0.12			0.80
Upper extremity	1.18	1.00–1.39		1.04	0.87–1.23
Lower extremity	1.21	1.01–1.44		1.02	0.85–1.23
Other/multiple	0.96	0.71–1.30		0.89	0.66–1.20
WBI ≥10% (Ref: WBI <10%)	1.02	0.88–1.19	0.77	1.28	1.09–1.51	0.002
Functional Comorbidity Index	0.94	0.80–1.12	0.50	0.99	0.83–1.18	0.88
Pre-injury wages ($10,000 increments)	1.00	0.92–1.08	0.97	0.61	0.54–0.68	<0.001
Large employer, ≥50FTE (Ref: <50 FTE)	1.13	1.00–1.27	0.045	1.03	0.91–1.16	0.66
Industry sector (Ref: Information, Finance, Real Estate, Professional)			0.02			0.07
Agriculture, Forestry, Fishing, Hunting	1.19	0.85–1.66		1.15	0.82–1.61
Construction, Utilities, Mining	0.80	0.60–1.07		0.93	0.69–1.26
Manufacturing	1.26	0.95–1.68		1.19	0.89–1.59
Retail/Wholesale Trade	0.85	0.65–1.12		0.81	0.62–1.07
Transportation, Warehousing	1.05	0.74–1.48		1.09	0.77–1.54
Administrative, Support, Other Services	1.05	0.81–1.36		1.09	0.84–1.42
Education, Health Care, Social Services	1.07	0.81–1.40		1.09	0.82–1.44
Arts, Entertainment, Hospitality	1.05	0.78–1.43		1.11	0.81–1.51
Hazard groupb	1.02	0.98–1.05	0.37	1.04	1.00–1.07	0.048

Note: In addition to covariates shown, models were fully stratified by year of initial injury (baseline hazard unique to each year).

Abbreviations: CI, confidence interval; FTE, full-time equivalent; HR, hazard ratio; WBI, whole body impairment; Ref, reference category.

^ap value on referent line reflects joint test for set of categories within variable.

^bThe HR represents the estimated increase in risk for each one-unit increase in hazard group (values ranged from 1 to 9).