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Table 4 Sensitivity analyses on NIS sample (Coefficients of opt-out variable)

From: Assessing the impact of state “opt-out” policy on access to and costs of surgeries and other procedures requiring anesthesia services

  Total number of surgical discharges Log Total number of surgical discharges Mean costs per surgical case Log Mean costs per surgical case
Main model 39.78 0.0529 1815.3*** 0.0840*
  (0.62) (1.08) (3.76) (2.43)
Subgroup analysis
 Early opt-outa vs control 103.9 0.0741 644.5 0.0183
  (1.50) (1.50) (1.42) (0.50)
 Late opt-outb vs control −185.4 0.0234 2461.0*** 0.120*
  (−1.14) (0.29) (4.42) (2.38)
 opt-out variable * late opt-outc −279.9 −0.0687 2202.9** 0.130*
  (−1.87) (−1.16) (3.09) (2.38)
Alternative definitions of surgical case
 Removing cases age <18 out of total surgical discharges 39.91 0.0410 1833.5** 0.0784*
  (0.61) (0.98) (3.41) (2.28)
 Removing all transplant DRGs and any craniotomy DRGs 38.84 0.0535 1757.2*** 0.0831*
  (0.61) (1.09) (3.75) (2.39)
 Include only hip and knee surgery procedures 24.12 0.00109 494.1 0.0292
  (1.55) (0.03) (0.63) (1.27)
Using partial covariates
 Exclude hospital characteristics 33.71 0.0477 1839.3*** 0.0762*
  (0.56) (1.08) (4.08) (2.72)
 Exclude hospital characteristics and county variables 6.887 0.0364 1903.8** 0.0637*
  (0.12) (0.70) (3.06) (2.10)
 Exclude hospital variables, county variables and t-1 year variables −110.4* −0.0561 1977.9** 0.0709***
  (−2.03) (−1.18) (2.91) (4.71)
  1. Notes: Costs were in 2011 dollar adjusted by hospital and related services CPI; *p < 0.05; **p < 0.01; ***p < 0.001
  2. aEarly opt out =1 for those hospitals in states opt out between 2001 and 2005 (i.e. IA, MN, NE, NH, NM, AK, KS, ND, OR, WA, MT, SD, WI)
  3. bLate opt out =1 for those hospitals in states opt out between 2009 and 2010 (i.e. CA, CO)
  4. cThis is the coefficient for the interaction term between opt-out variable and late opt out variable. The model was conducted on whole sample to test whether state opt out in recent year had different impact on outcomes comparing those opt out in early year