Table 2:
Difference-in-Differences Regression Results for Diagnosed Diabetes Prevalence and Hospitalization Rates
| Difference-in-Differences (N=2,915) |
Difference-in-Differences (accounts for pre-SIM differences) (N=2,900) |
|||
|---|---|---|---|---|
| Coefficient Estimate | 95% Confidence Interval | Coefficient Estimate | 95% Confidence Interval | |
| Variable | Diagnosed Diabetes Prevalence | |||
| SIM Initiative | 0.53*** | (0.39, 0.67) | 0.49*** | (0.33, 0.65) |
| Female | −0.03 | (−0.22, 0.15) | 0.07 | (−0.13, 0.28) |
| Age 40–64 y | 0.02 | (−0.07, 0.10) | 0.08 | (−0.04, 0.20) |
| Age 65+ y | 0.03 | (−0.06, 0.12) | −0.05 | (−0.20, 0.10) |
| Nonwhite | 0.03 | (−0.10, 0.15) | 0.10 | (−0.06, 0.26) |
| Uninsured | −0.05*** | (−0.08, −0.02) | −0.02 | (−0.05, 0.01) |
| Household income < 100% FPL | 0.00 | (−0.02, 0.03) | −0.01 | (−0.03, 0.01) |
| Year 2011 | 0.26*** | (0.19, 0.33) | 0.32*** | (0.18, 0.46) |
| Year 2012 | 0.33*** | (0.20, 0.46) | 0.54*** | (0.27, 0.80) |
| Year 2013 | 0.42*** | (0.23, 0.61) | 0.73*** | (0.33, 1.12) |
| Year 2014 | 0.11 | (−0.18, 0.39) | 0.62** | (0.06, 1.19) |
| Constant | 10.11* | (−0.55, 20.77) | 2.55 | (−11.18, 16.27) |
| Variable | Ambulatory Care-Sensitive Condition Hospitalization Rate | |||
| SIM Initiative | −0.37 | (−2.64, 1.89) | −5.34*** | (−8.54, −2.14) |
| Female | 0.24 | (−6.73, 7.21) | −1.86 | (−8.30, 4.58) |
| Age 40–64 y | 1.87* | (−0.15, 3.89) | 0.36 | (−2.75, 3.48) |
| Age 65+ y | 2.39** | (0.07, 4.70) | 1.60 | (−2.67, 5.87) |
| Nonwhite | −1.35 | (−4.01, 1.31) | −1.63 | (−5.84, 2.58) |
| Uninsured | 0.34 | (−0.22, 0.90) | −0.43 | (−1.19, 0.34) |
| Household income < 100% FPL | 0.03 | (−0.41, 0.46) | 0.21 | (−0.20, 0.63) |
| Year 2011 | −3.07*** | (−4.68, −1.47) | −6.78*** | (−10.35, −3.21) |
| Year 2012 | −9.39*** | (−11.97, −6.81) | −17.16*** | (−24.24, −10.08) |
| Year 2013 | −10.72*** | (−14.58, −6.85) | −21.78*** | (−32.55, −11.02) |
| Year 2014 | −9.44*** | (−15.01, −3.86) | −24.96*** | (−40.26, −9.66) |
| Constant | −69.06 | (−445.14, 307.01) | 137.44 | (−230.64, 505.51) |
| Variable | All-Cause Hospitalization Rate | |||
| SIM Initiative | 0.92 | (−6.67, 8.51) | −13.16*** | (−21.34, −4.97) |
| Female | −3.57 | (−23.69, 16.54) | −7.01 | (−20.65, 6.62) |
| Age 40–64 y | 5.37 | (−1.50, 12.25) | 0.19 | (−8.54, 8.92) |
| Age 65+ y | 5.30 | (−1.41, 12.01) | 7.57 | (−3.43, 18.57) |
| Nonwhite | −7.01* | (−14.92, 0.89) | −10.05** | (−18.87, −1.24) |
| Uninsured | 1.68* | (−0.09, 3.45) | −0.37 | (−2.12, 1.38) |
| Household income < 100% FPL | 0.18 | (−1.14, 1.50) | 0.14 | (−1.02, 1.30) |
| Year 2011 | −12.52*** | (−16.77, −8.27) | −20.35*** | (−28.77, −11.94) |
| Year 2012 | −27.63*** | (−35.40, −19.86) | −48.06*** | (−64.93, −31.19) |
| Year 2013 | −29.32*** | (−42.45, −16.20) | −59.05*** | (−83.81, −34.30) |
| Year 2014 | −21.33** | (−38.82, −3.83) | −63.59*** | (−98.84, −28.34) |
| Constant | 163.64 | (−956.63, 1283.91) | 607.29 | (−228.75, 1443.34) |
P<0.10,
P<0.05,
P<0.01
FPL indicates federal poverty level; SIM, State Innovation Model
County fixed effects and county-year trend parameter estimates not shown. For the county-year trends, year was coded as a continuous variable equal to the actual year minus 2010 so the first value would be zero; this coding only affects the estimate of the constant. Hospitalization rate is the number of hospitalizations per 1000 adults diagnosed with diabetes. The reference group for age was 20–39 year olds and for year was 2010. The sample size for the difference-in-differences model that accounted for pre-SIM differences had a smaller sample size due to dropping counties without common support.
Sources: Authors’ analysis of Centers for Disease Control and Prevention’s county-level estimates, Healthcare Cost and Utilization Project’s State Inpatient Databases, and Area Health Resources File