Geographic region Southeast 275 (62.5%) 146 (59.3%) 129 (66.5%) 0.10
Midwest 47 (10.7%) 23 (9.3%) 24 (12.4%)
West 98 (22.3%) 65 (26.4%) 33 (17.0%)
Northeast 20 (4.5%) 12 (4.9%) 8 (4.1%)
a Group comparisons with independent samples t-tests for continuous variables and chi-square tests for categorical variables
Lentz et al. BMC Health Services Research  (2018) 18:648 Page 6 of 14