Generalized linear mixed model of antibiotic prescription for pediatric RTIs: A) Effect estimates and B) measures of model fit and variance.
| A) | |||||
|---|---|---|---|---|---|
| EFFECT | EMPTY MODEL | BASIC MODEL WITH YEAR ONLY | WITH PATIENT COVARIATES | WITH PATIENT AND PHYSICIAN COVARIATES | WITH PATIENT, PHYSICIAN, AND REGIONAL COVARIATES |
| Random effect, variance (SE) | |||||
| Physician | 0.96 (0.023) | 0.95 (0.022) | 0.91 (0.011) | 0.78 (0.019) | 0.76 (0.019) |
| Fixed effects, OR (95% CI) | |||||
| Constant term | 0.27 (0.26–0.27) | 0.35 (0.34–0.36) | 0.18 (0.17–0.18) | 0.10 (0.09–0.11) | 0.10 (0.08–0.12) |
| Year (reference: 2005) | |||||
| • 2006 | 0.93 (0.91–0.95) | 0.94 (0.92–0.96) | 0.91 (0.88–0.93) | 0.90 (0.88–0.92) | |
| • 2007 | 0.89 (0.87–0.91) | 0.93 (0.91–0.95) | 0.88 (0.86–0.90) | 0.87 (0.85–0.89) | |
| • 2008 | 0.85 (0.83–0.87) | 0.92 (0.90–0.94) | 0.87 (0.85–0.89) | 0.86 (0.84–0.88) | |
| • 2009 | 0.58 (0.57–0.60) | 0.61 (0.60–0.63) | 0.58 (0.56–0.59) | 0.57 (0.56–0.59) | |
| • 2010 | 0.76 (0.74–0.78) | 0.92 (0.90–0.94) | 0.83 (0.81–0.86) | 0.83 (0.81–0.85) | |
| • 2011 | 0.75 (0.73–0.77) | 0.94 (0.92–0.96) | 0.86 (0.83–0.88) | 0.85 (0.82–0.87) | |
| Season (reference: Jun–Aug) | |||||
| • Mar–May | 0.98 (0.97–1.00) | 0.99 (0.97–1.00) | 1.05 (1.03–1.07) | 0.99 (0.97–1.02) | |
| • Sep–Nov | 0.80 (0.79–0.82) | 0.80 (0.79–0.82) | 0.86 (0.85–0.88) | 0.80 (0.77–0.82) | |
| • Dec–Feb | 0.99 (0.97–1.00) | 0.96 (0.94–0.98) | 1.06 (1.04–1.09) | 0.95 (0.92–0.98) | |
| Patient sex (reference: male) | |||||
| • Female | 0.97 (0.96–0.98) | 0.97 (0.96–0.98) | 0.97 (0.96–0.98) | ||
| Patient age (per y increase) | 1.08 (1.08–1.08) | 1.08 (1.08–1.08) | 1.08 (1.08–1.08) | ||
| Follow-up RTI visit | 0.98 (0.96–1.01) | 0.97 (0.95–1.00) | 0.97 (0.95–1.00) | ||
| QAIPPE (reference: 1) | |||||
| • 2 | 1.00 (0.98–1.02) | 1.00 (0.98–1.02) | 1.00 (0.98–1.02) | ||
| • 3 | 1.01 (0.99–1.03) | 1.01 (0.99–1.03) | 1.01 (0.99–1.03) | ||
| • 4 | 1.02 (1.00–1.04) | 1.02 (1.00–1.05) | 1.02 (1.00–1.04) | ||
| • 5 | 1.03 (1.01–1.05) | 1.04 (1.02–1.06) | 1.04 (1.02–1.06) | ||
| Diabetes | 1.08 (0.95–1.22) | 1.05 (0.93–1.19) | 1.05 (0.93–1.19) | ||
| Asthma | 1.06 (1.04–1.08) | 1.06 (1.04–1.08) | 1.06 (1.04–1.08) | ||
| Cystic fibrosis | 0.96 (0.80–1.16) | 0.97 (0.80–1.18) | 0.97 (0.80–1.18) | ||
| Immune deficiency | 0.92 (0.80–1.07) | 0.92 (0.79–1.06) | 0.92 (0.79–1.06) | ||
| Chronic liver disease | 1.07 (0.74–1.56) | 1.03 (0.70–1.52) | 1.00 (0.68–1.48) | ||
| Congestive heart failure | 1.30 (0.88–1.92) | 1.12 (0.75–1.69) | 1.12 (0.74–1.68) | ||
| COPD | 0.87 (0.78–0.98) | 1.14 (1.02–1.29) | 1.15 (1.02–1.29) | ||
| Chronic kidney disease | 0.90 (0.72–1.13) | 1.12 (0.89–1.40) | 1.12 (0.90–1.40) | ||
| Recent antibiotic use | 0.85 (0.83–0.87) | 0.86 (0.84–0.88) | 0.86 (0.84–0.88) | ||
| ADG sum | 0.97 (0.97–0.97) | 0.97 (0.97–0.97) | 0.97 (0.97–0.97) | ||
| Visits in past 3 y with this physician, % (reference: > 30) | |||||
| • 0 | 1.20 (1.18–1.22) | 1.21 (1.19–1.24) | 1.21 (1.19–1.24) | ||
| • ≤ 30 (but > 0) | 1.07 (1.05–1.09) | 1.07 (1.05–1.09) | 1.07 (1.05–1.09) | ||
| No. of different GPs seen in past 3 y | 1.02 (1.02–1.02) | 1.02 (1.02–1.02) | 1.02 (1.02–1.02) | ||
| Physician sex (reference: male) | |||||
| • Female | 0.89 (0.84–0.94) | 0.91 (0.86–0.96) | |||
| Specialty (reference: GP) | |||||
| • Emergency medicine physician | 0.79 (0.61–1.02) | 0.79 (0.62–1.02) | |||
| • Pediatrician | 0.47 (0.41–0.55) | 0.48 (0.42–0.56) | |||
| • Other | 0.88 (0.72–1.06) | 0.89 (0.73–1.07) | |||
| Visits for RTIs in the past 30 d, % (reference: > 20) | |||||
| • None | 1.34 (1.21–1.49) | 1.36 (1.23–1.51) | |||
| • ≤ 2.5 | 1.42 (1.35–1.49) | 1.45 (1.38–1.52) | |||
| • > 2.5–5 | 1.40 (1.34–1.45) | 1.42 (1.36–1.48) | |||
| • > 5–7.5 | 1.32 (1.27–1.37) | 1.33 (1.29–1.38) | |||
| • > 7.5–10 | 1.25 (1.21–1.30) | 1.26 (1.22–1.31) | |||
| • > 10–15 | 1.21 (1.17–1.25) | 1.22 (1.18–1.25) | |||
| • > 15–20 | 1.13 (1.10–1.16) | 1.13 (1.10–1.16) | |||
| Medical school graduation location (reference: Canada) | |||||
| • International | 1.77 (1.68–1.88) | 1.73 (1.63–1.83) | |||
| Daily patient volume (reference: 1st quartile [< 28 visits]) | |||||
| • 2nd quartile (28–37 visits) | 0.99 (0.97–1.01) | 0.99 (0.98–1.01) | |||
| • 3rd quartile (38–48 visits) | 0.97 (0.95–0.99) | 0.97 (0.95–0.99) | |||
| • 4th quartile (> 48 visits) | 0.94 (0.92–0.96) | 0.94 (0.92–0.97) | |||
| Years since medical school graduation (reference: 0–5) | |||||
| • 6–10 | 0.98 (0.93–1.03) | 0.99 (0.94–1.04) | |||
| • 11–15 | 1.07 (1.01–1.14) | 1.08 (1.02–1.15) | |||
| • 16–20 | 1.15 (1.08–1.22) | 1.16 (1.09–1.24) | |||
| • 21–25 | 1.21 (1.13–1.29) | 1.23 (1.15–1.31) | |||
| • 26–30 | 1.29 (1.21–1.39) | 1.32 (1.23–1.41) | |||
| • 31–35 | 1.32 (1.23–1.42) | 1.35 (1.26–1.46) | |||
| • 36–40 | 1.36 (1.25–1.47) | 1.39 (1.29–1.51) | |||
| • > 40 | 1.41 (1.28–1.56) | 1.46 (1.33–1.61) | |||
| No. of RTIs seen in the past y (reference: 1st quartile [≤ 248]) | |||||
| • 2nd quartile (249–490) | 1.10 (1.07–1.13) | 1.11 (1.08–1.14) | |||
| • 3rd quartile (491–972) | 1.17 (1.12–1.21) | 1.19 (1.15–1.23) | |||
| • 4th quartile (≥ 973) | 1.27 (1.21–1.33) | 1.31 (1.25–1.37) | |||
| LHA population aged > 65 y (per 10%) | 0.99 (0.98–1.00) | ||||
| LHA population aged < 15 y (per 10%) | 1.12 (1.06–1.17) | ||||
| Median age of LHA population (centred on mean) | 1.19 (1.11–1.27) | ||||
| Health authority (reference: Vancouver Coastal) | |||||
| • Interior | 1.07 (1.02–1.13) | ||||
| • Fraser | 1.00 (0.97–1.03) | ||||
| • Vancouver Island | 1.03 (0.98–1.08) | ||||
| • Northern | 1.20 (1.13–1.28) | ||||
| 28-d moving average apparent temperature | 0.99 (0.99–0.99) | ||||
| B) | |||||
|---|---|---|---|---|---|
| MEASURE | EMPTY MODEL | BASIC MODEL WITH YEAR ONLY | WITH PATIENT COVARIATES | WITH PATIENT AND PHYSICIAN COVARIATES | WITH PATIENT, PHYSICIAN, AND REGIONAL COVARIATES |
| Observations used, n | 671 342 | 671 342 | 662 202 | 645 815 | 645 094 |
| AIC | 616 216.2 | 692 274.7 | 666 759.5 | 648 692.3 | 647 788.8 |
| ICC,* % | 22.6 | 22.4 | 21.6 | 19.2 | 18.8 |
| MOR | 2.55 | 2.53 | 2.48 | 2.33 | 2.30 |
| PCV (relative to intercept-only model) at level of physician, % | NA | 1.49 | 5.86 | 18.55 | 20.82 |
| PCV (relative to previous model) at level of physician, % | NA | 1.49 | 4.44 | 13.48 | 2.78 |
ADG—aggregated diagnosis group, AIC—Akaike information criterion, COPD—chronic obstructive pulmonary disease, ICC—intraclass correlation, IQR—interquartile range, LHA—local health area, MOR—median odds ratio, NA—not applicable, OR—odds ratio, PCV—percent change in variance, QAIPPE—Quintile of Annual Income Per Person Equivalent, RTI—respiratory tract infection.
↵* ICC is the proportion of total variance attributable to between-physician differences.