Does geographical location impact the efficacy of oral antihypertensive therapy in pregnancy?

Abstract

To assess the efficacy of anti-hypertensive medications during pregnancy according to race, ethnicity and geographical location as current evidence is not clear in this regard. A subgroup meta-analysis of randomized controlled trials was performed. The efficacy of oral medications for chronic hypertension in pregnancy by geographical location [United States of America (USA) vs. rest of the World] was investigated. The location was used as a surrogate of racial identification and differences in health care systems and availability of medications that might affect the efficacy of the treatment. The number of patients in each group experiencing the following outcomes: small for gestational age (SGA), preeclampsia, severe hypertension were compared. Seven studies were identified. Subgroup analysis revealed that medications did not affect the occurrence of SGA. In six studies, therapies were protective for preeclampsia in the rest of the world but not in USA (p=0.02). Therapies were protective for severe hypertension. Our findings suggest that location does not affect the efficacy of medication in treating chronic hypertension during pregnancy. Geographical location may serve as a surrogate for genetic characteristics of a population of interest. However, it can also be influenced by other factors such as the heterogeneity of populations such as the USA.

Keywords: Geographical location; hypertensive disorders of pregnancy; oral therapy; preeclampsia; pregnancy.

Figure 1

Flow chart of included/excluded studies

Figure 2

Forest plot of risk ratio of occurrence of small for gestational age via the meta-analytic method RR: Risk ratio, CI: Confidence interval

Figure 3

Funnel plot of standard error (symmetry/asymmetry risk of bias evaluation) considering small for gestational age as outcome

Figure 4

Linear regression test of funnel plot asymmetry for small for gestational age (p=0.9257, indicating no evidence of publication bias)

Figure 5

Forest plot of risk ratio of occurrence of preeclampsia via the meta-analytic method RR: Risk ratio, CI: Confidence interval

Figure 6

Funnel plot of standard error (symmetry/asymmetry risk of bias evaluation) considering preeclampsia as outcome

Figure 7

Linear regression test of funnel plot asymmetry for preeclampsia (p=0.6847, indicating low-risk of publication bias)

Figure 8

Forest plot of risk ratio of occurrence of severe hypertension via the meta-analytic method RR: Risk ratio, CI: Confidence interval

Figure 9

Funnel plot of standard error (symmetry/asymmetry risk of bias evaluation) considering severe hypertension as outcome

Figure 10

Linear regression test of funnel plot asymmetry for severe hypertension (p=0.1208, indicating no evidence of publication bias)

Table 5

Risk-of-bias tool for randomized trials (Rob) 2 assessment for selected studies. D1: Bias arising from the randomization; process, D2: Bias due to deviations from the intended interventions, D3: Bias due to missing outcome data, D4: Bias in measurement of the outcome, D5: Bias in selection of the reported result