Table 2.

Study variables based on the Social Ecological Theory (n=17)

Author & Year	Individual	Interpersonal	Community	Organizational	Policy
Buntin (2009)	Age, gender, race, clinical complexity, medicaid coverage		Place of residence, rural area	Size, teaching status, medicare patient %, case mix index of hospital, low-income patient %	Post-acute care payment systems
Cram (2011)	Age, sex, race, comorbidities
Jorgenson (2015)	Age, gender, race, comorbidities, insurance		Rural-urban commuting area codes	% of Black patients at each facility; procedure volume	75% rule for inpatient rehab eligibility
Inneh (2016)	Age, gender, race/ethnicity, comorbidities		Median household income by zip code		BPCI
Schwarzkopf (2016)	Age, gender, race, comorbidities, insurance
Burke (2017)	Age, sex, race, ethnicity, comorbidities, insurance, hospitalization (urgency)	Marital status	Median income of residents	Ownership, size, geographic location
Lan (2017)	Age, gender, race, insurance, risk of mortality, illness severity		Patient residence, median income
Cram (2018)	Age, sex, race, comorbidities
Fang (2018)	Race				BPCI
Singh (2019)	Age, sex, comorbidities, insurance		MSA	MSA location, hospital annual MJR volume
Cavanaugh (2020)	Race, education, income, functional status, multimorbidity	Marital status, living arrangement	Geographic region, neighborhood socioeconomic status, levels of poverty		Medicare 60% rule
Kim (2020)	Age, sex, race, medicaid, medically complex			Teaching, safety-net, ownership, MJR volume	CJR
Reynolds (2020)	Gender, race, health insurance, number of chronic conditions
Klemt (2021)	Age, gender, BMI, insurance, race, comorbidities, preop meds	Marital status, social status
Chisari (2021a)	Age, gender, race, BMI, comorbidities				BPCI
Chisari (2021b)	Age, gender, comorbidities, BMI
Wu (2021)	Age, race BMI, comorbidities, functional status

^*Body mass index (BMI); Metropolitan statistical area (MSA); Bundled payment care initative (BPCI); Comprehensive joint replacement model (CJR)