Table 2.

Cohort characteristics stratified by 90-day opioid use post-surgery

Characteristic	90-day non-opioid user	90-day opioid user	Odds Ratio	95% Confidence Interval		P-value*
n (%)	1458 (82.3)	313 (17.7)
Age, mean (SD)	67.6 (9.8)	65.9 (9.2)	.982	.97	.994	0.004
Sex, female+	751 (51.5)	202 (64.5)	.584	.453	.752	< 0.001
Pre-op opioid user	192 (13.2)	118 (37.7)	3.99	3.033	5.25	< 0.001
Hospital, Private+	775 (53.2)	153 (48.8)	.843	.66	1.076	0.17
Surgery Joint
Knee	780 (53.5)	237 (75.7)	2.711	2.052	3.58	< 0.001
Bilateral Hip or Knee	66 (4.5)	22 (7.0)	1.595	.968	2.626	0.067
Previous THA/ TKA	400 (27.4)	73 (23.3)	.804	.604	1.07	0.135
Education, Year 10 or below+
Completed Year 11 or above	923 (63.3)	192 (61.3)	.93	0.722	1.198	0.574
Comorbid condition	1304 (89.4)	301 (96.2)	2.961	1.624	5.398	< 0.001
Acute major complication	1419 (97.3)	293 (93.6)	2.484	1.428	4.32	0.001
Post-major complication	1374 (94.2)	262 (83.7)	3.184	2.195	4.62	< 0.001
Pre-op opioid use	192 (13.2)	118 (37.7)	3.99	3.033	5.25	< 0.001
Tobacco use
Current smoker	110 (7.5)	42 (13.4)	1.903	1.303	2.78	< 0.001
Inpatient Rehabilitation	396 (27.2)	127 (40.6)	1.831	1.421	2.359	< 0.001
Employed at time of surgery	413 (28.3)	79 (25.2)	0.866	0.655	1.146	0.315
EQ-5D Baseline
Pain/Discomfort			1.55†	1.335	1.799	< 0.0001
No pain or discomfort	38 (2.6)	2 (0.6)
Slight pain or discomfort	248 (17.0)	31 (9.9)
Moderate pain or discomfort	694 (47.6)	132 (42.2)
Severe pain or discomfort	395 (27.1)	118 (37.7)
Extreme pain or discomfort	68 (4.7)	29 (9.3)
Baseline Oxford Knee or Hip Score, mean (SD)	21.8 (8.6)	18.7 (8.1)	.957	.943	.972	< 0.0001
ASA, 3 +	432 (30.3)	131 (43.2)	1.725	1.337	2.225	< 0.0001

Legend: Number and percentage shown unless otherwise stated; Reference = No, unless otherwise indicated; SD = standard deviation; Education = highest completed level; Year 11 or above = senior secondary high school

⁺Reference group

^*p-values based on univariate logistic regression

^†Odds Ratio is per increase in pain/discomfort level