Table 3

Negative binomial regression results

Individuals who are only covered by Medicare (N=1126) and individuals who are covered by Medicare and other health insurances (N=1462) in hospital stayIndividuals who are only covered by Medicare (N=3032) and individuals who are covered by Medicare and other health insurances (N=3307) in doctor’s visit
Visit times of last 2 years (visit ≥1)Medicare only (group 1)Medicare and other health insurances (group 2)Medicare only (group 1)Medicare and other health insurances (group 2)
IRR95% CIIRR95% CIIRR95% CIIRR95% CI
Region
 New England and Mid AtlanticRefRefRefRef
 EN Central and WN Central0.9020.756 to 1.0760.797*0.691 to 0.9190.743*0.668 to 0.8260.884†0.797 to 0.981
 S Atlantic1.0470.886 to 1.2360.9030.784 to 1.0390.847*0.763 to 0.9391.157*1.043 to 1.283
 ES Central and WS Central1.0580.882 to 1.2700.740*0.634 to 0.8650.846*0.755 to 0.9470.9970.893 to 1.115
 Mountain and Pacific0.8820.728 to 1.0690.726*0.613 to 0.8590.806*0.722 to 0.9001.140†1.017 to 1.278
Age
 <65RefRefRefRef
 65–740.802†0.672 to 0.9570.757*0.658 to 0.8700.748*0.665 to 0.8400.719*0.646 to 0.801
 75–840.781*0.658 to 0.9270.663*0.575 to 0.7640.733*0.651 to 0.8240.686*0.614 to 0.767
 >850.785†0.646 to 0.9540.644*0.545 to 0.7610.717*0.626 to 0.8220.781*0.686 to 0.890
Gender
 MaleRefRefRefRef
 Female1.111†1.002 to 1.2330.872*0.793 to 0.9571.0020.940 to 1.0681.0430.977 to 1.113
Race
 NH whiteRefRefRefRef
 NH black0.9370.819 to 1.0721.0350.916 to 1.1700.9320.857 to 1.0150.823*0.754 to 0.898
 Hispanic1.0660.898 to 1.2651.0660.893 to 1.2721.0110.904 to 1.1290.9290.817 to 1.057
 Other0.8130.605 to 1.0931.0810.853 to 1.3711.359*1.135 to 1.6281.172‡0.974 to 1.410
Education
 Less than high school educationRefRefRefRef
 High school/GED0.824*0.721 to 0.9431.1170.976 to 1.2771.0480.957 to 1.1490.9290.842 to 1.025
 Undergraduate0.8590.724 to 1.0200.9140.773 to 1.0811.174*1.052 to 1.3100.9330.830 to 1.048
 Graduate0.8730.689 to 1.1070.9340.750 to 1.1621.230*1.073 to 1.4111.208*1.054 to 1.385
Chronic disease
 No chronic diseaseRefRefRefRef
 Only one chronic disease0.8290.549 to 1.2520.9830.671 to 1.4401.712*1.450 to 2.0211.467*1.243 to 1.731
 More than one chronic disease1.1090.760 to 1.6191.2610.884 to 1.7992.261*1.941 to 2.6342.262*1.939 to 2.639
Employment status
 Full-timeRefRefRefRef
 Part-time0.8650.607 to 1.2321.1150.801 to 1.5501.1320.942 to 1.3601.0920.907 to 1.316
 Unemployed1.0020.679 to 1.4781.3100.942 to 1.8201.706*1.363 to 2.1351.351*1.090 to 1.674
 Retired1.1470.841 to 1.5641.562*1.185 to 2.0581.358*1.152 to1.283*1.089 to 1.513
Household income
 Lower incomeRefRefRefRef
 Middle income0.9110.702 to 1.1811.0420.862 to 1.2601.133‡0.997 to0.9510.847 to 1.068
 Upper income0.8920.702 to 1.1330.9410.764 to 1.1590.9740.859 to0.9310.822 to 1.054
  • We show ORs and 95% CI here. Counts do not sum to 4098 or 4651 due to missing values for some of the independent variables.

  • *Significant at 1% level (two-tailed test).

  • †Significant at 5% level (two-tailed test).

  • ‡Significant at 10% level (two-tailed test).

  • EN, East North; ES, East South; GED, General Educational Development; NH, non-Hispanic; S, South; WN, West North; WS, West South.