Table 4

Multivariable regression results

OutcomeSecure messaging intensityModel A
Model B
nRR(95% CI)P*nRR(95% CI)P*
A1C <7%14,075<0.00113,908<0.001
Nonverified0.95(0.90–1.01)0.92(0.87–0.98)
0 threads, identity verified11
1–3 threads1.06(0.97–1.15)1.08(1.00–1.18)
4–12 threads1.08(0.98–1.20)1.13(1.02–1.25)
≥12 threads1.29(1.10–1.50)1.36(1.16–1.58)
Blood pressure <130/80 mmHg10,1810.15010,0790.155
Nonverified0.92(0.86–0.99)0.92(0.87–0.99)
0 threads, identity verified11
1–3 threads1.00(0.92–1.10)1.01(0.92–1.11)
4–12 threads0.97(0.87–1.09)0.98(0.87–1.09)
≥12 threads1.00(0.80–1.26)0.98(0.78–1.24)
LDL cholesterol <100 mg/dl11,6370.25511,487<0.001
Nonverified0.97(0.93–1.01)0.94(0.90–0.98)
0 threads, identity verified11
1–3 threads0.97(0.91–1.02)0.99(0.93–1.05)
4–12 threads1.02(0.96–1.10)1.07(1.00–1.15)
≥12 threads0.99(0.87–1.13)1.01(0.89–1.14)
Total outpatient visits15,427<0.00115,237<0.001
Nonverified1.01(0.97–1.06)0.98(0.95–1.02)
0 threads, identity verified11
1–3 threads1.03(0.98–1.09)1.05(1.01–1.10)
4–12 threads1.27(1.18–1.36)1.19(1.13–1.25)
≥12 threads1.97(1.76–2.20)1.39(1.26–1.53)
Primary care visits15,427<0.00115,237<0.001
Nonverified1.04(0.99–1.08)0.99(0.96–1.03)
0 threads, identity verified11
1–3 threads1.01(0.96–1.07)1.02(0.98–1.07)
4–12 threads1.18(1.10–1.26)1.11(1.05–1.18)
≥12 threads1.74(1.57–1.94)1.32(1.19–1.45)
Specialty care visits15,427<0.00115,237<0.001
Nonverified0.97(0.92–1.03)0.96(0.91–1.01)
0 threads, identity verified11
1–3 threads1.06(0.98–1.14)1.08(1.01–1.15)
4–12 threads1.36(1.24–1.48)1.26(1.16–1.36)
≥12 threads2.17(1.87–2.51)1.43(1.25–1.64)
Emergency visits15,427<0.00115,237<0.001
Nonverified1.33(1.16–1.54)1.17(1.05–1.32)
0 threads, identity verified11
1–3 threads0.90(0.76–1.07)1.04(0.90–1.21)
4–12 threads1.19(0.94–1.51)1.19(0.98–1.44)
≥12 threads2.34(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.