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. Author manuscript; available in PMC: 2015 Mar 6.
Published in final edited form as: J Polit Econ. 2015 Feb 1;123(1):170–214. doi: 10.1086/677756

Table 1.

Balance: Demographics and Comorbidities

1st Quartile 2nd Quartile 3rd Quartile 4th Quartile
Ambulance Avg log(Hospital Spending) 8.830 8.914 8.938 9.017**
Predicted One-Year Mortality 0.333 0.332 0.332 0.333
One-Year Mortality 0.380 0.366 0.351 0.362**
Patient Age 81.461 81.277 81.330 81.394
Male 0.376 0.383 0.377 0.379
Race: White 0.888 0.885 0.885 0.880**
Race: Black 0.076 0.078 0.077 0.080**
Race: Other 0.035 0.036 0.037 0.038**
Miles Transported with Patient 7.088 6.915 6.861 7.066
Ambulance: Emergency Transport 0.655 0.673 0.673 0.656
Ambulance: Advanced Life Support 0.867 0.870 0.871 0.860
Ambulance IV Fluids Administered 0.059 0.057 0.061 0.056
Ambulance: Intubation Performed 0.002 0.002 0.002 0.002
Patient Origin: Home or Nursing Home 0.792 0.812 0.813 0.784
Comorbidity: Hypertension 0.184 0.182 0.173 0.182
Comorbidity: Stroke 0.022 0.019 0.018 0.020
Comorbidity: Cerebrovascular Disease 0.031 0.029 0.028 0.030
Comorbidity: Renal Failure Disease 0.049 0.048 0.045 0.049
Comorbidity: Dialysis 0.004 0.004 0.004 0.005
Comorbidity: COPD 0.089 0.087 0.085 0.086
Comorbidity: Pneumonia 0.060 0.056 0.055 0.057**
Comorbidity: Diabetes 0.083 0.080 0.078 0.080
Comorbidity: Protein Caloria Malnutrition 0.019 0.016 0.015 0.017
Comorbidity: Dementia 0.059 0.050 0.048 0.055**
Comorbidity: Paralysis 0.025 0.022 0.020 0.023**
Comorbidity: Peripheral Vascular Disease 0.048 0.046 0.044 0.046
Comorbidity: Metastatic Cancer 0.026 0.026 0.025 0.025
Comorbidity: Trauma 0.036 0.032 0.030 0.034**
Comorbidity: Substance Abuse 0.023 0.024 0.022 0.023
Comorbidity: Major Psych. Disorder 0.015 0.013 0.012 0.014
Comorbidity: Chronic Liver Disease 0.003 0.004 0.004 0.004

Note: N=351,701. Some ambulance measures have smaller sample sizes, largely because they are not recorded in the in the outpatient reimbursement system. N=330,607 for Ambulance measures for Advanced Life Support, IV administration and distance travelled. Columns correspond to quartiles based on the difference in ambulance company average hospital spending relative to average hospital spending in the ZIP, mirroring our estimation strategy. The last column reports significance test for difference between 1st and 4th Quartile means

*

p < 0.05;

**

p < 0.01

Source: 2002–2010 Medicare Part A Claims Data