Table 4:

Multivariable ordinal regression model for the effect of year of diagnosis on number of refills

Odds Ratio Estimatesa
	1 vs 0 refillsb			>= 2 vs 0 refillsb
Characteristics	Estimate	95% Wald Confidence Limits		Estimate	95% Wald Confidence Limits
Year of diagnosis
2008 vs 2007	1.028	0.870	1.214	0.833	0.694	1.001
2009 vs 2007	1.025	0.866	1.213	0.923	0.771	1.105
2010 vs 2007	0.986	0.832	1.169	0.894	0.747	1.069
2011 vs 2007	0.983	0.828	1.167	0.953	0.798	1.139
2012 vs 2007	0.940	0.793	1.115	0.874	0.732	1.043
2013 vs 2007	0.910	0.763	1.085	0.911	0.760	1.091
2014 vs 2007	0.926	0.774	1.107	0.814	0.676	0.981
2015 vs 2007	0.962	0.802	1.154	0.843	0.699	1.017
2016 vs 2007	0.969	0.805	1.167	0.767	0.631	0.932
2017 vs 2007	0.886	0.734	1.068	0.667	0.549	0.810
Age at diagnosis
< 10y vs >= 50y	0.247	0.190	0.321	0.106	0.062	0.182
10 – 20y vs >= 50y	0.656	0.561	0.768	0.238	0.184	0.307
20 – 50y vs >= 50y	1.051	0.953	1.158	0.780	0.710	0.856
Gender
Female vs Male	0.714	0.660	0.773	0.790	0.727	0.858
Region
Midwest vs South	1.028	0.937	1.128	1.015	0.920	1.119
Northeast vs South	0.881	0.753	1.031	0.863	0.733	1.017
West vs South	1.113	1.001	1.237	1.187	1.065	1.323
Opioid use in the past 12 months
Yes vs No	1.661	1.527	1.806	6.090	5.519	6.719
Inpatient stay
Yes vs No	2.343	2.065	2.659	3.630	3.181	4.143
Burn severity
More severe vs Less severe	1.716	1.572	1.874	1.601	1.461	1.755
Elixhauser score
1 vs 0	1.032	0.933	1.141	1.142	1.023	1.276
2 vs 0	1.117	0.977	1.278	1.451	1.276	1.65
>=3 vs 0	1.141	0.998	1.304	1.818	1.615	2.046
Arthritis (RA/OA)
Yes vs No	1.076	0.950	1.219	2.255	2.049	2.481
Cancer
Yes vs No	1.111	0.871	1.417	1.083	0.887	1.321
Alcohol Abuse
Yes vs No	1.170	0.936	1.464	0.792	0.646	0.972
Drug Abuse
Yes vs No	1.344	1.088	1.661	2.163	1.839	2.544
Depression
Yes vs No	1.125	1.011	1.253	1.466	1.333	1.612
Tobacco Use
Yes vs No	1.303	1.154	1.471	1.698	1.533	1.881

^aAdjusted for all variables

^bThe ordinal regression model contrasts each response level against the reference level (refills = 0)