Table 4.

Association between physician age, 30 day readmission rate, and costs of care in patients admitted to hospital

Physician age	No of admissions (No of physicians*)	Adjusted patient outcomes† (95% CI)	Adjusted odds ratio or difference† (95% CI)	P value
30 day readmission rate
Continuous‡:
For every 10 years	722 999 (18 854)	—	1.00 (0.99 to 1.01)	0.82
Categorical:
<40	305 763 (10 172)	15.0% (14.9% to 15.1%)	Reference
40-49	274 664 (8019)	15.0% (14.9% to 15.1%)	1.00 (0.99 to 1.02)	0.84
50-59	112 623 (3320)	14.9% (14.7% to 15.1%)	0.99 (0.97 to 1.02)	0.58
≥60	29 949 (1086)	14.8% (14.4% to 15.3%)	0.99 (0.95 to 1.03)	0.55
Total part B costs
Continuous‡:
For every 10 years	780 197 (18 956)	—	2.4% (2.0% to 2.8%)	<0.001
Categorical:
<40	327 707 (10 211)	$1008 ($1004 to $1012)	Reference
40-49	296 680 (8071)	$1027 ($1022 to $1032)	1.8% (1.3% to 2.4%)	<0.001
50-59	122 758 (3364)	$1056 ($1048 to $1064)	4.7% (3.8% to 5.6%)	<0.001
≥60	33 052 (1111)	$1071 ($1055 to $1088)	6.3% (4.5% to 8.0%)	<0.001

*Total number of physicians varies between continuous and categorical analyses because some physicians moved to higher age category during study period.

†Adjusted for patient and physician characteristics and hospital fixed effects. Standard errors were clustered at physician level. Logistic regression was used for readmission analyses, and generalized linear model with a log link and a gamma distribution was used for cost analyses.

‡Estimates from continuous models should be interpreted as average odds ratio across all physician age categories.