Table 5.

Multilevel Logistic Regression Analyses With 3 Levels: Child, Family, and General Practitioner (GP)

Explanatory VariablesEmpty Model Intercept (SE)Model 1a Intercept (SE)Model 2a,b Intercept (SE)Model 3a,b Intercept (SE)
CI = confidence interval; GP = general practitioner; OR = odds ratio; SE = standard error.
a Model 1 (age-groups), model 2 (age-groups, child characteristics), model 3 (age-groups, child characteristics, family characteristics, GP characteristics).
b In these models we corrected for the presence of an asthma diagnosis in the child (model 2: OR = 262; 95% CI, 219–312; model 3: OR = 264; 95% CI, 221–315).
c The variance at the lowest level (children) is not determined because the outcome is dichotomous.
d Correlation between the variances of the 2 defined age-groups on the GP level.
e ICC between the 2 upper levels (families and GPs). ICC is the relative contribution of GP to sum of family and GP variance.
Age 1–17 y−2.580 (0.039)
Age 1–5 y−2.210 (0.054)−3.629 (0.100)−3.645 (0.091)
Age 6–17 y−2.779 (0.039)−3.573 (0.071)−3.605 (0.060)
OR (95% CI)OR (95% CI)
Sex, male1.25 (1.13–1.39)1.25 (1.13–1.39)
Shortness of breath/dyspnea20.7 (14.3–29.9)20.2 (13.9–29.2)
Wheezing51.5 (24.7–107)49.7 (23.8–104)
Cough6.51 (5.68–7.47)6.46 (5.64–7.40)
Acute bronchitis/bronchiolitis9.04 (7.57–10.8)8.91 (7.45–10.6)
Acute upper respiratory tract infection1.47 (1.26–1.72)1.47 (1.26–1.72)
Pneumonia2.10 (1.44–3.07)2.11 (1.44–3.09)
Allergic rhinitis2.12 (1.68–2.69)2.10 (1.66–2.67)
No. of contacts with GP1.10 (1.08–1.12)1.10 (1.08–1.12)
Presence of parental asthma1.74 (1.41–2.15)
Prescribing volume of GP1.99 (1.60–2.47)
Patients 0–17 y ≥25% per GP0.59 (0.44–0.78)
Percentage of children with asthma diagnosis per GP0.88 (0.83–0.93)
Variance (SE)cVariance (SE)Variance (SE)Variance (SE)
Between-family variance0.567 (0.071)0.535 (0.071)0.474 (0.112)0.471 (0.111)
Between-GP variance
Age 1–17 y0.119 (0.022)
Age 1–5 y0.209 (0.042)0.751 (0.134)0.547 (0.106)
Age 6–17 y0.097 (0.022)0.384 (0.071)0.214 (0.047)
Covariance0.118 (0.025)0.479 (0.083)0.284 (0.058)
CorrelationsCorrelationsCorrelationsCorrelations
Correlation of GP variance between age-groupsd0.830.890.83
Intraclass correlatione
Age 1–17 y0.17
Age 1–5 y0.380.720.64
Age 6–17 y0.290.650.51