Table 3

Results of negative binomial regressions: effects on utilisation (number of doctor visits)

 
 
Model I (n=19638)Model II* (n=17101)
IRR95% CIIRR95% CI
Sex [female] 1.25 1.22 to 1.29 1.23 1.20 to 1.27
Age [ref=young (age<40 years)]    
 Middle (40–64 years) 0.92 0.88 to 0.95 0.94 0.90 to 0.97
 Old (age>64 years)1.000.95 to 1.051.040.99 to 1.09
Area deprivation GIMD 2010 [ref=Q1, least deprived]  
 Q20.960.92 to 1.01 0.96 0.91 to 1.00
 Q30.970.92 to 1.021.000.95 to 1.05
 Q4 0.92 0.88 to 0.97 0.95 0.90 to 0.99
 Q5 (most deprived) 0.84 0.80 to 0.88 0.86 0.82 to 0.90
Settlement structure [ref=1 city]    
 2 urban district 0.93 0.89 to 0.97 0.93 0.89 to 0.97
 3 rural district with population concentration 0.90 0.86 to 0.94 0.89 0.86 to 0.93
 4 rural district 0.90 0.86 to 0.94 0.90 0.86 to 0.94
Children in household [yes]1.000.96 to 1.041.030.99 to 1.07
GP within 20 minutes [yes]1.000.97 to 1.040.990.96 to 1.02
German [no]1.030.96 to 1.110.970.91 to 1.03
Equivalent household disposable income [ref=Q1 high; >€32 564]
 Q2 (>€24 031–32 564)0.990.94 to 1.040.990.95 to 1.04
 Q3 (>€18 552–24 031) 0.94 0.89 to 0.99 0.94 0.90 to 0.99
 Q4 (>€13 829–18 552) 0.91 0.87 to 0.96 0.90 0.85 to 0.94
 Q5 (low; ≤€13 829) 0.87 0.82 to 0.92 0.86 0.82 to 0.91
Education [ref=less than high school]    
 High school 1.12 1.07 to 1.17 1.15 1.10 to 1.20
 More than high school 1.18 1.12 to 1.25 1.19 1.13 to 1.26
Health status [ref=very good]    
 Good 1.39 1.30 to 1.49 1.43 1.33 to 1.54
 Satisfactory 1.93 1.80 to 2.08 1.97 1.82 to 2.14
 Poor 2.91 2.68 to 3.15 2.91 2.67 to 3.17
 Bad 4.09 3.70 to 4.52 3.91 3.54 to 4.32
Number of morbidities 1.28 1.26 to 1.30 1.25 1.24 to 1.27
Concerns about own health [ref=not concerned at all]
 Somewhat concerned 1.18 1.13 to 1.23 1.21 1.16 to 1.26
 Very concerned 1.47 1.39 to 1.55 1.54 1.46 to 1.63
Type of health insurance [private health insurance] 1.05 1.01 to 1.111.040.99 to 1.10
Intercept 1.24 1.11 to 1.39 1.23 1.09 to 1.38
Goodness of fit (value deviance/DF)1.091.24
  • Incidence rate ratio in bold=statistically significant at 5% level.

  • Missing values in total: education (n=856), health status (n=42), concerns about own health (n=66) and type of health insurance (n=35).

  • Models I and II are full models.

  • *Weighting factor was used: calculation with normalised weights.

  • [], category tested in a dichotomous variable; [ref=], reference category for more than two characteristics; DF, degrees of freedom; GIMD, German Index of Multiple Deprivation; GP, general practitioner; Q, quintile.