Table 3.

Adjusted health care costs and utilization, results from propensity score-adjusted regression analyses.

	Non-adherent vs. adherent to clinical practice guidelines that advise against early MRI for patients without “red flags”
Any utilization of services	RR (95% CI)
CT	0.40 (0.18, 0.92)
Radiograph	1.04 (0.81, 1.34)
Injection	1.93 (1.43, 2.62)
Surgery	2.16 (1.28, 3.66)
Number of office visits	IRR (95% CI)
Chiropractic	0.82 (0.69, 0.97)
PT/OT	1.54 (1.33, 1.80)
Outpatient	1.52 (1.30, 1.77)
Costs*	CR (95% CI)
Outpatient services	1.52 (1.33, 1.70)
Inpatient services	3.10 (1.72, 4.47)
Non-medical†	1.87 (1.34, 2.39)
Disability compensation	1.63 (1.34, 1.92)
Total costs	1.62 (1.38, 1.86)

Ratios compare workers whose imaging experience was not adherent to clinical practice guidelines (received early MRI) to workers with imaging adherent to guidelines (workers who received an MRI after the first 6 weeks of injury or did not receive an MRI at all).

Abbreviations: RR, relative risk; IRR, incidence rate ratio; CR, cost ratio; MRI, magnetic resonance imaging; CT, computed tomography; PT/OT, physical therapy or occupational therapy.

^*Costs refer to total reimbursed amounts for procedures and visits that occurred within 1 year following injury, inflation adjusted to 2005 equivalents, based on Medical Consumer Price Index.

^† Non-medical costs include reimbursement for vocational (return-to-work) assistance or rehabilitation, employability assessments, worker transportation, medical devices, and other costs not included in other cost categories.