Table 4.
Adjusted Associations between Change in Primary Care Workforce and 2011 Outcomes
| Results from Unadjusted Models (per Beneficiary) | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Mortality | Hospitalizations for Ambulatory Care–Sensitive Conditions | Total Emergency Department Visits | |||||||
| Risk Ratio | 95% CI | p‐value | Risk Ratio | 95% CI | p‐value | Risk Ratio | 95% CI | p‐value | |
| Workforce measure | |||||||||
| Main model | |||||||||
| An increase of one primary care physicians per 10,000 populationa | 0.997 | (0.995–1.000) | .045 | 0.995 | (0.993–0.998) | <0.05 | 1.001 | (1.000–1.002) | .165 |
| Associated changes based on 2001 U.S. average by increase 1 per 10,000 workforce | Associated reduction of 15.1 per 100,000 | Associated reduction of 39.7 per 100,000 | Associated increase of 24.4 per 100,000 | ||||||
| Model with interaction term | |||||||||
| An increase of one primary care physicians per 10,000 populationa | 0.995 | (0.991–0.999) | <.05 | 0.994 | (0.990–0.997) | <0.05 | 1.000 | (0.998–1.001) | .538 |
| 2001 × difference in primary care physicians per 10,000 population | 1.000 | (1.000–1.001) | .206 | 1.000 | (1.000–1.001) | 0.352 | 1.0001 | (1.0000–1.0003) | .042 |
| Main model | |||||||||
| An increase of one Medicare primary care full‐time equivalents per 10,000 beneficiariesb | 0.985 | (0.982–0.989) | <.05 | 0.981 | (0.978–0.983) | <0.05 | 0.981 | (0.980–0.983) | <.05 |
| Associated changes based on 2001 U.S. average by increase 1 per 10,000 workforce | Associated reduction of 82.8 per 100,000 | Associated reduction of 160.8 per 100,000 | Associated reduction of 712.3 per 100,000 | ||||||
| Model with interaction term | |||||||||
| An increase of one Medicare primary care full‐time equivalents per 10,000 beneficiariesb | 0.982 | (0.968–0.995) | <.05 | 0.995 | (0.984–1.006) | 0.345 | 0.976 | (0.972–0.981) | <.05 |
| 2001 × difference in Medicare primary care full‐time equivalents per 10,000 beneficiaries | 1.001 | (0.999–1.002) | .581 | 0.998 | (0.996–1.000) | <0.05 | 1.0008 | (1.0001–1.0014) | <.05 |
To calculate associated change, for example, we applied the annual morality for 2001 of 5,610 per 100,000 from Table 1 to compute the reduction in the number of deaths per 100,000 as: 5,610*(1 − 0.9973) = 15.14 for per capita measure; 5,610*(1 − 0.9852) = 82.76 for full‐time equivalents measure.
The risk ratios show the direction of change.
If the value of risk ratio is >1 then adding workforce is associated with an increased outcome.
If the value of risk ratio is <1, then adding workforce is associated with a decreased outcome.
*Adjusted for 2011 individual patient characteristics (age, sex, race, chronic conditions), 2001 area patient characteristics, difference in area patient characteristics, 2001 area outcome, 2001 workforce, and area urban indicator, area median household income, area specialty supply, and area hospital bed supply (hospitalizations and emergency department visits).
Age–sex‐adjusted office‐based American Medical Association Masterfile clinically active primary care physicians per 10,000 total population.
Age–sex–race‐adjusted office‐based primary care full‐time equivalents per 10,000 study beneficiaries.