Table 2.
Hepatitis C virus antibody screening at four months
| Substudy | Completed antibody screening, n (%; 95% CI)* | Difference, % (95% CI) | P value† |
|---|---|---|---|
| Substudy A: opt in or opt out | |||
| Letter only (n=813) | 156 (19.2; 16.5 to 21.9) | 23.9 (19.6 to 28.2) | <0.001 |
| Letter+laboratory order (n=829) | 357 (43.1; 39.7 to 46.4) | ||
| Substudy B: content | |||
| Usual care messaging (n=9828) | 1431 (14.6; 13.9 to 15.3) | −1.0 (−1.9 to 0.0) | 0.06 |
| Behavioral messaging (n=9833) | 1341 (13.6; 13.0 to 14.3) | ||
| Substudy B: communication mode | |||
| Mailed letter (n=1897) | 337 (17.8; 16.0 to 19.5) | −4.0 (−5.8 to −2.1) | <0.001 |
| Patient portal message (n=9498) | 1313 (13.8; 13.1 to 14.5) | ||
*
Includes only patients screened using antibody testing.
†
P value less than 0.05 was threshold for statistical significance using χ2 test of proportions.