Table 2.
Comparisons of process-of-care estimates between IV models, as-treated models, and post-hoc IV modelsa for each outcome
| Outcome/Process measure | Methods | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| As-treated methods | IV methods | Post-hoc IV methodsa | |||||||
| Coefficient (SE) |
P-value | 95% CI | Coefficient (SE) |
P-value | 95% CI | Coefficient (SE) |
P-value | 95% CI | |
| SBP change | |||||||||
| No. Counseling session | −0.45 (0.24) |
0.06 | (−0.92, −0.02) | −10.82 (14.79) |
0.46 | (−39.80, 18.16) | −5.30 (1.13) |
<0.001 | (−7.52, −3.08) |
| No. Medications | −0.05 (0.46) |
0.92 | (−0.94, 0.85) | 10.78 (23.19) |
0.64 | (−34.66, 56.23) | −7.19 (1.57) |
<0.001 | (−10.27, −4.12) |
| DBP change | |||||||||
| No. Counseling session | −0.10 (0.14) |
0.49 | (−0.38, 0.18) | −0.43 (3.04) |
0.89 | (−6.38, 5.53) | −1.65 (0.52) |
0.002 | (−2.68, −0.63) |
| No. Medications | −0.28 (0.23) |
0.23 | (−0.74, 0.18) | −1.67 (5.00) |
0.74 | (−11.48, 8.14) | −2.68 (0.81) |
0.001 | (−4.26, −1.10) |
| Total costs | |||||||||
| No. Counseling session | 33.02 (4.69) |
< 0.001 | (23.80, 42.24) | −383.15 (677.64) |
0.57 | (−1711.31, 945.01) | 89.08 (14.74) |
< 0.001 | (60.18, 117.98) |
| No. Medications | 90.57 (8.74) |
< 0.001 | (73.41, 107.74) | 832.18 (1051.69) |
0.43 | (−1229.11, 2893.46) | 191.81 (25.08) |
< 0.001 | (142.66, 240.96) |
a
Post-hoc instrumental variable methods included one process measure as an endogenous regressor and the other process measure as a control variable.