Table 2. Difference-in-Differences Results After Program Launch: Part Aa,b.
| Variable | Difference-in-differences for HbA1c (95% CI), percentage pointsc | Constant | N × Td | R 2 | F | ||||
|---|---|---|---|---|---|---|---|---|---|
| Treated | 2015-2016 | 2016-2017 | 2017-2018 | 2018-2019 | |||||
| Overall model | −0.10 (−0.17 to −0.03) | NA | NA | NA | NA | 20.68 (−2.99 to 44.35) | 49 752 | 0.65 | 19.00 |
| By years | NA | −0.05 (−0.10 to 0.01) | −0.10 (−0.15 to −0.05) | −0.12 (−0.23 to −0.01) | −0.14 (−0.24 to −0.03) | 20.80 (−2.87 to 44.47) | 49 752 | 0.65 | 12.86 |
| Men | NA | −0.05 (−0.13 to 0.03) | −0.07 (−0.13 to −0.004) | −0.10 (−0.23 to 0.04) | −0.14 (−0.26 to −0.02) | 25.62 (−3.75 to 55.00) | 28 399 | 0.63 | 3.95 |
| Women | NA | −0.04 (−0.13 to 0.05) | −0.14 (−0.24 to −0.05) | −0.15 (−0.26 to −0.05)I | −0.14 (−0.24 to −0.03) | 0.67 (−40.97 to 42.30) | 21 353 | 0.68 | 20.26 |
| Whitee | NA | −0.05 (−0.12 to 0.01) | −0.11 (−0.17 to −0.05) | −0.11 (−0.24 to 0.02) | −0.15 (−0.26 to −0.04) | 12.88 (−5.01 to 30.76) | 40 299 | 0.64 | 8.91 |
| Non-Whitee | NA | 0.003 (−0.10 to 0.10) | −0.04 (−0.16 to 0.09) | −0.11 (−0.27 to 0.04) | 0.01 (−0.16 to 0.17) | 52.37 (−31.47 to 136.22) | 9045 | 0.69 | 4.99 |
| Age ≤55 y | NA | −0.005 (−0.09 to 0.08) | −0.09 (−0.19 to 0.02) | −0.11 (−0.29 to 0.06) | −0.14 (−0.28 to −0.001) | 7.13 (−10.64 to 24.90) | 23 752 | 0.65 | 3.13 |
| Age >55 y | NA | −0.08 (−0.16 to −0.004) | −0.11 (−0.16 to −0.07) | −0.13 (−0.20 to −0.06) | −0.13 (−0.22 to −0.04) | 55.16 (14.42 to 95.90) | 26 000 | 0.62 | 11.01 |
Abbreviations: HbA1c, hemoglobin A1c; NA, not applicable.
Standard errors were clustered at practice level.
Fixed-effects models for individuals were estimated. Fixed effects models control for all time invariant observable and unobservable characteristics. All models include time dummies and a quadratic for age.
To convert these estimates from Diabetes Control and Complications Trial (%) to International Federation of Clinical Chemistry (mmol/mol), multiply by 10.93.
Sample sizes are N × T for an unbalanced panel.
White categories: British, Irish, other White. Non-White categories: Black African, Black Caribbean, Black British, other Black, mixed Black, Bangladeshi, Pakistani, Indian, Sri Lankan, British Asian, other South Asian, mixed Asian, Chinese, other ethnic groups, other mixed groups.