Table 2 Consent and retention rates at 3-month follow-up according to incentive schemes (n = 1246)
Incentive schemes | Consent rate n (%) | Risk ratio (95% CI) | P-value | Retention rate n (%) | Risk ratio (95% CI) | P-value |
|---|---|---|---|---|---|---|
All (n = 1246) | 462 (37.1) | 287 (23.0) | ||||
No incentive | 114/316 (36.1) | Ref | 64/316 (20.3) | Ref | ||
Promised HK$100 | 110/326 (33.7) | 0.94 (0.76, 1.16) | 0.54 | 69/326 (21.2) | 1.05 (0.77, 1.41) | 0.78 |
Promised HK$200 | 107/283 (37.8) | 1.05 (0.85, 1.29) | 0.66 | 68/283 (24.0) | 1.19 (0.88, 1.60) | 0.27 |
Mixed incentive | 131/321 (40.8) | 1.13 (0.93, 1.38) | 0.22 | 86/321 (26.8) | 1.32 (1.00, 1.76) | 0.053 |
Participants who consented (n = 462) | 287 (62.1) | |||||
No incentive | – | – | – | 64/114 (56.1) | Ref | |
Promised HK$100 | – | – | – | 69/110 (62.7) | 1.12 (0.90, 1.39) | 0.21 |
Promised HK$200 | – | – | – | 68/107 (63.6) | 1.13 (0.91, 1.41) | 0.20 |
Mixed incentive not receiving prepaid | – | – | – | 33/67 (49.3) | 0.88 (0.66, 1.18) | 0.38 |
Mixed incentive receiving prepaid | – | – | – | 53/64 (82.8) | 1.48 (1.21, 1.80) | <0.01 |