Table 4.

Results of Negative Binomial Regression Examining the Association Between the Number of VOCs and the Number of Opioid Prescriptions Prescribed to Patients with SCD (N = 3368)

	IRR	95% Confidence Limits		P value
		Lower	Upper
Number of VOC events	1.095	1.078	1.111	<0.0001

Abbreviations: IRR, incidence rate ratio; SCD, sickle cell disease; VOC, vaso-occlusive crisis.

Other significant covariates with higher expected opioid use included: age groups (13 and older compared to 2–12), increase in number of nonopioid pain medications, increase in number of nonstudy SCD-related medications, and increase in number of SCD-related complications.