Table 4.
Multivariable regression results
| Outcome | Secure messaging intensity | Model A |
Model B |
||||||
|---|---|---|---|---|---|---|---|---|---|
| n | RR† | (95% CI) | P * | n | RR† | (95% CI) | P * | ||
| A1C <7% | 14,075 | <0.001 | 13,908 | <0.001 | |||||
| Nonverified | 0.95 | (0.90–1.01) | 0.92 | (0.87–0.98) | |||||
| 0 threads, identity verified | 1 | — | 1 | — | |||||
| 1–3 threads | 1.06 | (0.97–1.15) | 1.08 | (1.00–1.18) | |||||
| 4–12 threads | 1.08 | (0.98–1.20) | 1.13 | (1.02–1.25) | |||||
| ≥12 threads | 1.29 | (1.10–1.50) | 1.36 | (1.16–1.58) | |||||
| Blood pressure <130/80 mmHg | 10,181 | 0.150 | 10,079 | 0.155 | |||||
| Nonverified | 0.92 | (0.86–0.99) | 0.92 | (0.87–0.99) | |||||
| 0 threads, identity verified | 1 | — | 1 | — | |||||
| 1–3 threads | 1.00 | (0.92–1.10) | 1.01 | (0.92–1.11) | |||||
| 4–12 threads | 0.97 | (0.87–1.09) | 0.98 | (0.87–1.09) | |||||
| ≥12 threads | 1.00 | (0.80–1.26) | 0.98 | (0.78–1.24) | |||||
| LDL cholesterol <100 mg/dl | 11,637 | 0.255 | 11,487 | <0.001 | |||||
| Nonverified | 0.97 | (0.93–1.01) | 0.94 | (0.90–0.98) | |||||
| 0 threads, identity verified | 1 | — | 1 | — | |||||
| 1–3 threads | 0.97 | (0.91–1.02) | 0.99 | (0.93–1.05) | |||||
| 4–12 threads | 1.02 | (0.96–1.10) | 1.07 | (1.00–1.15) | |||||
| ≥12 threads | 0.99 | (0.87–1.13) | 1.01 | (0.89–1.14) | |||||
| Total outpatient visits | 15,427 | <0.001 | 15,237 | <0.001 | |||||
| Nonverified | 1.01 | (0.97–1.06) | 0.98 | (0.95–1.02) | |||||
| 0 threads, identity verified | 1 | — | 1 | — | |||||
| 1–3 threads | 1.03 | (0.98–1.09) | 1.05 | (1.01–1.10) | |||||
| 4–12 threads | 1.27 | (1.18–1.36) | 1.19 | (1.13–1.25) | |||||
| ≥12 threads | 1.97 | (1.76–2.20) | 1.39 | (1.26–1.53) | |||||
| Primary care visits | 15,427 | <0.001 | 15,237 | <0.001 | |||||
| Nonverified | 1.04 | (0.99–1.08) | 0.99 | (0.96–1.03) | |||||
| 0 threads, identity verified | 1 | — | 1 | — | |||||
| 1–3 threads | 1.01 | (0.96–1.07) | 1.02 | (0.98–1.07) | |||||
| 4–12 threads | 1.18 | (1.10–1.26) | 1.11 | (1.05–1.18) | |||||
| ≥12 threads | 1.74 | (1.57–1.94) | 1.32 | (1.19–1.45) | |||||
| Specialty care visits | 15,427 | <0.001 | 15,237 | <0.001 | |||||
| Nonverified | 0.97 | (0.92–1.03) | 0.96 | (0.91–1.01) | |||||
| 0 threads, identity verified | 1 | — | 1 | — | |||||
| 1–3 threads | 1.06 | (0.98–1.14) | 1.08 | (1.01–1.15) | |||||
| 4–12 threads | 1.36 | (1.24–1.48) | 1.26 | (1.16–1.36) | |||||
| ≥12 threads | 2.17 | (1.87–2.51) | 1.43 | (1.25–1.64) | |||||
| Emergency visits | 15,427 | <0.001 | 15,237 | <0.001 | |||||
| Nonverified | 1.33 | (1.16–1.54) | 1.17 | (1.05–1.32) | |||||
| 0 threads, identity verified | 1 | — | 1 | — | |||||
| 1–3 threads | 0.90 | (0.76–1.07) | 1.04 | (0.90–1.21) | |||||
| 4–12 threads | 1.19 | (0.94–1.51) | 1.19 | (0.98–1.44) | |||||
| ≥12 threads | 2.34 | (1.61–3.41) | 1.66 | (1.23–2.26) | |||||
Model A is unadjusted. Model B is adjusted for age, sex, overall medical comorbidity, diabetes severity, depression severity, insurance type, PCP's participation in secure messaging, PCP's age, PCP's sex, and PCP panel size.
*Wald tests for composite linear hypotheses.
†Rate ratio.