Results of negative binomial regressions: effects on utilisation (number of doctor visits)
| | Model I (n=19638) | Model II* (n=17101) | ||
| IRR | 95% CI | IRR | 95% 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) | 1.00 | 0.95 to 1.05 | 1.04 | 0.99 to 1.09 |
| Area deprivation GIMD 2010 [ref=Q1, least deprived] | ||||
| Q2 | 0.96 | 0.92 to 1.01 | 0.96 | 0.91 to 1.00 |
| Q3 | 0.97 | 0.92 to 1.02 | 1.00 | 0.95 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] | 1.00 | 0.96 to 1.04 | 1.03 | 0.99 to 1.07 |
| GP within 20 minutes [yes] | 1.00 | 0.97 to 1.04 | 0.99 | 0.96 to 1.02 |
| German [no] | 1.03 | 0.96 to 1.11 | 0.97 | 0.91 to 1.03 |
| Equivalent household disposable income [ref=Q1 high; >€32 564] | ||||
| Q2 (>€24 031–32 564) | 0.99 | 0.94 to 1.04 | 0.99 | 0.95 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 1.11 | 1.04 | 0.99 to 1.10 |
| Intercept | 1.24 | 1.11 to 1.39 | 1.23 | 1.09 to 1.38 |
| Goodness of fit (value deviance/DF) | 1.09 | 1.24 | ||
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.