. 2020 Jan 10;3(1):e1918663. doi: 10.1001/jamanetworkopen.2019.18663

Table 5. Risk-Adjusted Regression and Instrumental Variable Estimates for the Association Between Surgery Utilization and Cost Outcomes for Medicare Patients With Proximal Humerus Fracture in 2011 and Stratified Subgroups.

Stratified Models	Cost Outcomes, $
	Treatment Period^a			Outcome Period^b
	Shoulder^c	Non-Shoulder^d	Total^e	Shoulder	Non-Shoulder	Total
Instrumental variables estimates
Total cohort (N = 72 823)	5358^f	3555^g	8913^f	−983^f	−2179	−3117
Age <80 y (n = 36 216)	5906^f	4598^g	10 505^f	−1583^f	−3113	−4696
Age ≥80 y (n = 36 607)	4590^f	1755	6345^g	−157	−1734	−1891
Charlson Comorbidity Index score²²
<2 (n = 33 389)	4722^f	414	5137^g	−681^g	−1792	−2473
≥2 (n = 39 434)	5940^f	6352^h	12 292^f	−1166^h	−2810	−3976
Function-Related Indicators score²³
<2 (n = 44 820)	5678^f	2970ⁱ	8648^f	−1047^f	255	−798
≥2 (n = 28 003)	4543^f	4278	8822^g	−700	−8905ⁱ	−9605ⁱ
Risk-adjusted estimates
Total cohort (N = 72 823)	11 378^f	5900^f	17 278^f	621^f	919^f	1541^f
Age <80 y (n = 36 216)	10 528^f	5211^f	15 740^f	678^f	955^f	1633^f
Age ≥80 y (n = 36 607)	12 498^f	6708^f	19 206^f	557^f	1148^f	1706^f
Charlson Comorbidity Index score²²
<2 (n = 33 389)	10 702^f	4995^f	15 697^f	623^f	600^g	1223^f
≥2 (n = 39 434)	12 048^f	6798^f	18 847^f	620^f	1269^f	1889^f
Function-Related Indicators score²³
<2 (n = 44 820)	11 030^f	5342^f	16 373^f	613^f	885^f	1498^f
≥2 (n = 28 003)	12 103^f	7020^f	19 123^f	641^f	990^g	1632^f

^{^a}

Treatment period is days 0 to 60.

^{^b}

Outcome period is days 61 to 365.

^{^c}

Part A and B shoulder-related payments made by Medicare for the beneficiary.

^{^d}

Part A and B non–shoulder-related payments made by Medicare for the beneficiary.

^{^e}

Total Part A and B shoulder-related and non–shoulder-related payments made by Medicare for the beneficiary.

^{^f}

P < .001.

^{^g}

P < .05.

^{^h}

P < .01.

^ⁱ

P < .10.