Table 3.
Health plan characteristics associated with rates of antibiotic utilization
| Characteristic | Bivariate results | Multivariable results |
|---|---|---|
| Mean rate of antibiotic utilization PMPYa | Beta coefficient (95% CI)b | |
| Plan type | ||
| HMO, HMO/POS combined | 0.79 | -- |
| POS | 0.88 | .08 (−0.11 to 0.27) |
| Profit status | ||
| For profit | 0.90 | 0.06 (0.01 to 0.10) |
| Non-profit | 0.84 | -- |
| Accreditation status | ||
| Excellent | 0.89a | -- |
| Commendable | 0.78 | −0.08 (−0.15 to −0.01) |
| Other | 0.88 | 0.01 (−0.06 to 0.04) |
| Plan size | ||
| <100,000 enrollees | 0.88 | −0.02 (−0.06 to 0.02) |
| ≥ 100,000 enrollees | 0.88 | -- |
| Beta coefficient | ||
| % of plan physicians in primary care specialtiesc | 0.21 | 0.44 (0.16 to 0.71) |
| % of plan physicians board certified | −0.43 | −0.56 (−0.89 to −0.23) |
| Regione | ||
| Northeast | 0.07a | 0.09 (0.03 to 0.15) |
| Midwest | 0.12 | 0.13 (0.07 to 0.19) |
| South | 0.16 | 0.16 (0.11 to 0.22) |
| West | Referent | -- |
Rate of utilization for plan enrollees age 0–64, adjusted for the age and sex distribution of plans
Significant at P < 0.05 on bivariate analysis
For variables entered as categories, the beta -coefficient in the multivariable analysis corresponds to the adjusted difference in number of prescriptions PMPY compared to the reference group. For example, for-profit plans utilized 0.06 more antibiotics PMPY than did non-profit plans. For variables entered as a continuous value, the beta-coefficient corresponds to the adjusted difference in the number of antibiotic fills PMPY if a plan had 0% of that characteristic vs. 100% of that characteristic. For example, if a plan had 100% primary care physicians, it would dispense 0.44 more antibiotics PMPY than if that plan had 0% primary care physicians. Similarly, if a plan had 50% primary care physicians, it would dispense 0.044 more fills PMPY than a plan with 40% primary care physicians (e.g., 10% of 0.44).
Primary care specialties include adult primary care physicians, geriatrics, obstetrics-gynecology, and pediatrics
Data for analyses of primary care specialties, board certification, and national region were available for 218 of 229 plans. In the multivariable analysis, complete data were available for 209 of 229 plans
In the Western United States, the mean rate of antibiotic utilization was 0.78 fills PMPY. Thus, on bivariate analyses, plans in the South had a 21% higher rate of antibiotic utilization than plans in the West, calculated as (0.78 + 0.16) divided by 0.78. Regions included the following states: Northeast (CT, ME, MA, NH, NJ, NY, PA, RI, VT); Midwest (IL, IN, IA, KS, MI, MN, MO, NE, ND, OH, SD, WI); South (AL, AR, DE, DC, FL, GA, KY, LA, MD, MS, NC, OK, SC, TN, TX, VA, WV); West (AK, AZ, CA, CO, HI, ID, MT, NV, NM, OR, UT, WA, WY).