Table 3. Sensitivity analysis of aHRs of vaccination in risk reduction of ischemic stroke in the influenza season.
| Unvaccinated patients | Vaccinated patients | P for trend | |||
|---|---|---|---|---|---|
| 1 vaccination | 2 or 3 vaccinations | ≥ 4 vaccinations | |||
| aHR (95% CI) | aHR (95% CI) | aHR (95% CI) | aHR (95% CI) | ||
| Main model† | 1.00 | 0.91 (0.72, 1.15) | 0.62 (0.49, 0.79)*** | 0.40 (0.31, 0.51)*** | <0.001 |
| Additional covariates‡ | |||||
| Main model + warfarin | 1.00 | 0.90 (0.71, 1.14) | 0.62 (0.49, 0.79)*** | 0.39 (0.30, 0.50)*** | <0.001 |
| Main model + aspirin | 1.00 | 0.91 (0.72, 1.14) | 0.62 (0.49, 0.79)*** | 0.40 (0.31, 0.51)*** | <0.001 |
| Main model + statin | 1.00 | 0.91 (0.72, 1.15) | 0.62 (0.49, 0.79)*** | 0.40 (0.31, 0.51)*** | <0.001 |
| Main model + ACEI | 1.00 | 0.91 (0.72, 1.15) | 0.62 (0.49, 0.79)*** | 0.40 (0.31, 0.51)*** | <0.001 |
| Main model + metformin | 1.00 | 0.91 (0.72, 1.14) | 0.62 (0.49, 0.78)*** | 0.39 (0.31, 0.51)*** | <0.001 |
| Subgroup effects | |||||
| Age, y | |||||
| 55–74 | 1.00 | 1.09 (0.77, 1.53) | 0.87 (0.63, 1.21) | 0.50 (0.36, 0.70)*** | <0.001 |
| ≥75 | 1.00 | 0.71 (0.52, 0.97)* | 0.45 (0.31, 0.63)*** | 0.35 (0.24, 0.51)*** | <0.001 |
| Sex | |||||
| Women | 1.00 | 0.65 (0.45, 0.94)* | 0.47 (0.33, 0.68)*** | 0.41 (0.29, 0.58)*** | <0.001 |
| Men | 1.00 | 1.22 (0.90, 1.67) | 0.81 (0.59, 1.13) | 0.40 (0.28, 0.57)*** | <0.001 |
| CCI+ | |||||
| 0 | 1.00 | 0.62 (0.34, 1.13) | 0.57 (0.32, 1.00) | 0.39 (0.22, 0.68)*** | 0.001 |
| 1 | 1.00 | 0.81 (0.47, 1.37) | 0.74 (0.46, 1.18) | 0.46 (0.28, 0.74)** | 0.002 |
| 2 | 1.00 | 1.21 (0.76, 1.91) | 0.64 (0.38, 1.07) | 0.40 (0.24, 0.66)*** | <0.001 |
| ≥3 | 1.00 | 0.87 (0.60, 1.26) | 0.46 (0.31, 0.70)*** | 0.29 (0.18, 0.46)*** | <.001 |
| Diabetes | |||||
| No | 1.00 | 0.86 (0.64, 1.15) | 0.57 (0.43, 0.78)*** | 0.39 (0.29, 0.53)*** | <0.001 |
| Yes | 1.00 | 0.97 (0.66, 1.42) | 0.66 (0.45, 0.99)*** | 0.37 (0.23, 0.59)*** | <0.001 |
| Dyslipidemia | |||||
| No | 1.00 | 1.00 (0.76, 1.32) | 0.52 (0.38, 0.72)*** | 0.42 (0.31, 0.57)*** | <0.001 |
| Yes | 1.00 | 0.71 (0.46, 1.08) | 0.78 (0.54, 1.13) | 0.30 (0.19, 0.48)*** | <0.001 |
| Hypertension | |||||
| No | 1.00 | 0.53 (0.31, 0.92)* | 0.57 (0.34, 0.94)* | 0.36 (0.22, 0.60)*** | <0.001 |
| Yes | 1.00 | 1.04 (0.80, 1.35) | 0.62 (0.47, 0.81)*** | 0.39 (0.29, 0.53)*** | <0.001 |
| Warfarin | |||||
| <28 cDDD | 1.00 | 0.93 (0.69, 1.24) | 0.56 (0.41, 0.76)*** | 0.39 (0.28, 0.54)*** | <0.001 |
| ≥28 cDDD | 1.00 | 0.85 (0.58, 1.26) | 0.71 (0.49, 1.03) | 0.39 (0.26, 0.56)*** | <0.001 |
| Aspirin | |||||
| <28 cDDD | 1.00 | 0.90 (0.55, 1.47) | 0.49 (0.28, 0.85)** | 0.42 (0.22, 0.80)** | <0.001 |
| ≥28 cDDD | 1.00 | 0.87 (0.67, 1.14) | 0.64 (0.49, 0.84)** | 0.37 (0.28, 0.49)*** | <0.001 |
| Statin | |||||
| <28 cDDD | 1.00 | 0.89 (0.67, 1.18) | 0.53 (0.39, 0.72)*** | 0.43 (0.32, 0.59)*** | <0.001 |
| ≥28 cDDD | 1.00 | 0.93 (0.62, 1.41) | 0.76 (0.52, 1.11) | 0.34 (0.22, 0.51)*** | <0.001 |
| ACEI | |||||
| <28 cDDD | 1.00 | 0.58 (0.34, 1.02) | 0.49 (0.28, 0.85)* | 0.33 (0.17, 0.62)*** | <0.001 |
| ≥28 cDDD | 1.00 | 1.01 (0.78, 1.32) | 0.67 (0.51, 0.87)** | 0.42 (0.32, 0.55)*** | <0.001 |
| Metformin | |||||
| <28 cDDD | 1.00 | 0.83 (0.63, 1.10) | 0.59 (0.44, 0.78)*** | 0.41 (0.31, 0.54)*** | <0.001 |
| ≥28 cDDD | 1.00 | 1.09 (0.70, 1.70) | 0.68 (0.43, 1.08) | 0.35 (0.21, 0.58)*** | <0.001 |
*P < 0.05 **P < 0.01 ***P < 0.001
HR: hazard ratio
aHR: adjusted hazard ratio
+CCI: Charlson comorbidity index
†The main model was adjusted for age; sex; Charlson comorbidity index; comorbidities of diabetes, hypertension, dyslipidemia, congestive heart failure, vascular disease, pneumonia, and dialysis; urbanization level; and monthly income by using propensity scores.
‡The models were adjusted for covariates in the main model and each additional listed covariate.