Comparative safety of tramadol and other opioids following total hip and knee arthroplasty

BMC Geriatrics

Table 3 Risk differences comparing postoperative opioid use for 90-day outcomes among older Medicare beneficiaries

Comparisons	90-day All-cause SAE	90-day Composite SAE
Comparisons	RD, % (95% CLs)	RD, % (95% CLs)
Tramadol vs Oxycodone (reference)
Unadjusted	1.94* (0.31, 3.52)	0.35 (-0.41, 1.08)
Intention-to-Treat	0.78 (-1.00, 2.57)	0.14 (-0.66, 1.06)
Per-protocol	-0.49 (-5.66, 5.67)	3.01 (-0.48, 7.89)
Tramadol vs Hydrocodone (reference)
Unadjusted	2.82* (1.32, 4.37)	0.30 (-0.40, 0.96)
Intention-to-Treat	1.11 (-0.64, 2.77)	0.05 (-0.71, 0.84)
Per-protocol	3.94 (-4.30, 11.61)	3.54 (-0.88, 9.03)

Notes: 90-day treatment-specific risks and risk differences were estimated from survival curves standardized to the joint distribution of covariates. The 95% CLs were estimated using the percentile-method from 500 bootstrap replications. Risks differences were multiplied by 100 and thus presented as percentage point differences. Outcome definitions for SAEs are listed in Additional Table 4
Abbreviations: ED emergency department, SAE serious adverse events, RD risk difference, CL confidence limits
^*p < 0.05

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