Table 1.
Coefficient statistics of unadjusted and multivariable meta-regression on the association between blood pressure change and 24 hour urinary sodium change and other covariates
| Dependent variables and studies | Independent variables | Unadjusted | Multivariable | ||
|---|---|---|---|---|---|
| Coefficient* (95% CI) | P value | Coefficient* (95% CI) | P value | ||
| Change in SBP (mm Hg) | |||||
| All studies (135 data points) | Change of 24 hour urinary sodium (mmol) | 0.007 (−0.002 to 0.016) | 0.106 | 0.022 (0.013 to 0.031) | <0.001 |
| Duration of intervention (days) | −0.003 (−0.006 to 0.001) | 0.124 | 0.000 (−0.003 to 0.003) | 0.849 | |
| Mean age (years) | 0.121 (0.073 to 0.169) | <0.001 | 0.111 (0.046 to 0.177) | 0.001 | |
| Percentage of female sex | 2.258 (−0.794 to 5.309) | 0.146 | −0.412 (−3.170 to 2.346) | 0.768 | |
| Percentage of white ethnicity | −3.039 (−5.397 to −0.680) | 0.012 | −2.957 (−5.000 to −0.913) | 0.005 | |
| Mean baseline SBP (mm Hg) | 0.102 (0.065 to 0.138) | <0.001 | 0.074 (0.030 to 0.118) | 0.001 | |
| Studies with ≤14 days' intervention (77 data points) | Change of 24 hour urinary sodium (mmol) | 0.015 (−0.001 to 0.030) | 0.064 | 0.021 (0.008 to 0.034) | 0.002 |
| Duration of intervention (days) | 0.208 (−0.084 to 0.500) | 0.160 | 0.071 (−0.182 to 0.324) | 0.577 | |
| Mean age (years) | 0.180 (0.106 to 0.254) | <0.001 | 0.105 (−0.006 to 0.217) | 0.064 | |
| Percentage of female sex | 2.701 (−1.438 to 6.841) | 0.198 | −0.233 (−4.031 to 3.566) | 0.903 | |
| Percentage of white ethnicity | −5.061 (−8.923 to −1.199) | 0.011 | −2.787 (−6.343 to 0.770) | 0.123 | |
| Mean baseline SBP (mm Hg) | 0.132 (0.080 to 0.185) | <0.001 | 0.076 (0.002 to 0.150) | 0.044 | |
| Studies with >14 days' intervention (58 data points) | Change of 24 hour urinary sodium (mmol) | 0.043 (0.019 to 0.067) | 0.001 | 0.043 (0.017 to 0.068) | 0.002 |
| Duration of intervention (days) | −0.003 (−0.006 to −0.001) | 0.016 | 0.000 (−0.002 to 0.003) | 0.813 | |
| Mean age (years) | 0.107 (0.013 to 0.201) | 0.027 | 0.107 (0.012 to 0.203) | 0.028 | |
| Percentage of female sex | 0.523 (−4.924 to 5.970) | 0.848 | −0.421 (−5.337 to 4.496) | 0.864 | |
| Percentage of white ethnicity | −1.251 (−3.973 to 1.471) | 0.361 | −3.342 (−6.071 to −0.614) | 0.017 | |
| Mean baseline SBP (mm Hg) | 0.067 (0.004 to 0.129) | 0.036 | 0.058 (−0.003 to 0.120) | 0.062 | |
| Studies with duration >14 days and sodium reduction <=100 mmol (48 data points) | Change of 24 hour urinary sodium (mmol) | 0.059 (0.023 to 0.094) | 0.002 | 0.058 (0.022 to 0.093) | 0.002 |
| Duration of intervention (days) | −0.003 (−0.005 to −0.001) | 0.007 | 0.001 (−0.001 to 0.003) | 0.410 | |
| Mean age (years) | 0.113 (0.029 to 0.198) | 0.010 | 0.110 (0.032 to 0.188) | 0.007 | |
| Percentage of female sex | 0.945 (−4.278 to 6.169) | 0.717 | 0.155 (−3.854 to 4.164) | 0.938 | |
| Percentage of white ethnicity | −1.302 (−3.943 to 1.340) | 0.326 | −3.497 (−5.724 to −1.271) | 0.003 | |
| Mean baseline SBP (mm Hg) | 0.083 (0.025 to 0.141) | 0.006 | 0.087 (0.035 to 0.140) | 0.002 | |
| Change in DBP (mm Hg) | |||||
| All studies (136 data points) | Change of 24 hour urinary sodium (mmol) | 0.000 (−0.006 to 0.006) | 0.972 | 0.007 (0.001 to 0.013) | 0.028 |
| Duration of intervention (days) | −0.001 (−0.003 to 0.001) | 0.555 | 0.000 (−0.002 to 0.002) | 0.980 | |
| Mean age (years) | 0.068 (0.036 to 0.100) | <0.001 | 0.041 (−0.002 to 0.084) | 0.062 | |
| Percentage of female sex | −0.373 (−2.327 to 1.582) | 0.707 | −1.480 (−3.343 to 0.383) | 0.118 | |
| Percentage of white ethnicity | −1.102 (−2.569 to 0.366) | 0.140 | −0.909 (−2.249 to 0.430) | 0.182 | |
| Mean baseline DBP (mm Hg) | 0.102 (0.071 to 0.133) | <0.001 | 0.088 (0.049 to 0.127) | <0.001 | |
| Studies with ≤14 days' intervention (77 data points) | Change of 24 hour urinary sodium (mmol) | 0.003 (−0.007 to 0.014) | 0.531 | 0.007 (−0.002 to 0.015) | 0.134 |
| Duration of intervention (days) | 0.302 (0.127 to 0.478) | 0.001 | 0.174 (0.006 to 0.343) | 0.043 | |
| Mean age (years) | 0.104 (0.055 to 0.154) | <0.001 | 0.021 (−0.054 to 0.095) | 0.586 | |
| Percentage of female sex | −0.381 (−3.011 to 2.249) | 0.774 | −1.357 (−3.722 to 1.007) | 0.256 | |
| Percentage of white ethnicity | −1.230 (−3.590 to 1.130) | 0.302 | −0.570 (−2.701 to 1.561) | 0.596 | |
| Mean baseline DBP (mm Hg) | 0.126 (0.086 to 0.166) | <0.001 | 0.099 (0.036 to 0.162) | 0.003 | |
| Studies with >14 days' intervention (59 data points) | Change of 24 hour urinary sodium (mmol) | 0.015 (0.001 to 0.029) | 0.035 | 0.013 (−0.002 to 0.029) | 0.094 |
| Duration of intervention (days) | −0.001 (−0.003 to 0.000) | 0.157 | 0.000 (−0.002 to 0.002) | 0.983 | |
| Mean age (years) | 0.022 (−0.039 to 0.083) | 0.472 | 0.035 (−0.033 to 0.103) | 0.308 | |
| Percentage of female sex | −1.213 (−4.464 to 2.039) | 0.458 | −1.263 (−4.617 to 2.091) | 0.453 | |
| Percentage of white ethnicity | −0.780 (−2.472 to 0.911) | 0.359 | −1.493 (−3.353 to 0.368) | 0.113 | |
| Mean baseline DBP (mm Hg) | 0.049 (−0.011 to 0.109) | 0.110 | 0.048 (−0.015 to 0.110) | 0.134 | |
| Studies with duration >14 days and sodium reduction ≤100 mmol (49 data points) | Change of 24 hour urinary sodium (mmol) | 0.018 (−0.002 to 0.037) | 0.081 | 0.013 (−0.010 to 0.035) | 0.258 |
| Duration of intervention (days) | −0.001 (−0.002 to 0.000) | 0.049 | 0.000 (−0.002 to 0.001) | 0.810 | |
| Mean age (years) | 0.032 (−0.019 to 0.082) | 0.210 | 0.041 (−0.017 to 0.099) | 0.162 | |
| Percentage of female sex | −1.343 (−4.122 to 1.437) | 0.336 | −0.753 (−3.557 to 2.050) | 0.591 | |
| Percentage of white ethnicity | −0.370 (−1.848 to 1.109) | 0.617 | −0.979 (−2.544 to 0.586) | 0.214 | |
| Mean baseline DBP (mm Hg) | 0.059 (0.006 to 0.111) | 0.029 | 0.058 (0.003 to 0.113) | 0.040 | |
SBP=systolic blood pressure; DBP=diastolic blood pressure.
*
The coefficient means the change of the dependent variable (change in SBP or DBP) with each unit increase of the independent variables.