The Incidence of Pregnancy Hypertension in the Community Level Interventions for Pre-Eclampsia (CLIP) Trials - Population-Level Data from India, Pakistan, Mozambique, and Nigeria

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Background: Most estimates of pregnancy hypertension in lessdeveloped countries are from hospital-based cross-sectional surveys and are probably over-estimates. We aimed to estimate population-based rates by standardised methods in intervention clusters of the Community-Level Interventions in Pre-eclampsia (CLIP) cluster randomised trials (NCT01911494). Methods: In study regions, all pregnant women were CLIP-eligible and identified in their homes or local primary health centres (2013-17). This analysis includes women in intervention clusters who both received at least one community health worker (CHW) visit and had delivered by trial end. Trained CHWs provided supplementary hypertension-oriented care that included standardised blood pressure (BP) measurement using a semiautomated device validated in pregnancy. Based on gestational age at presentation, hypertension (BP ≥140/90mmHg) was 'chronic' (<20 weeks) or 'gestational' (≥20 weeks). 'Pre-eclampsia' was gestational hypertension with ≥1 proteinuria or a relevant end-organ complication. A multi-level regression model was used to compare hypertension rates and types between countries (p<0·05 significant). Results: In 28,420 pregnancies (27 clusters), pregnancy hypertension incidence was significantly lower in Pakistan (9·3%) than India (10·3%), Mozambique (10·9%), or Nigeria (10·2%) (p=0·001). Most hypertension was diastolic only (46·4% India, 72·7% Pakistan, 61·3% Mozambique, and 63·3% Nigeria). Chronic hypertension was more common in sub-Saharan Africa (2·5% Mozambique, 2·8% Nigeria) than South Asia (1·2% India, 1·5%Pakistan) (p<0·001). At first presentation with elevated BP, gestational hypertension was most common, particularly in Mozambique (8·4%) compared with India (6·9%), Pakistan (6·5%) or Nigeria (7·1%) (p<0·001); preeclampsia was most common in India (3·8%), followed by Nigeria (3·0%), Pakistan (2·4%), and Mozambique (2·3%) (p<0·001). Women rarely presented with eclampsia (1 in India and 3 in Nigeria). Conclusions: Pregnancy hypertension incidence (overall and by type) are at least as high in less-, compared with more-, developed settings. Most women present with gestational hypertension, which is amenable to surveillance and timed delivery aimed at decreasing morbidity and mortality. Clinical Trial Number: (NCT01911494) Funding Statement: This study was funded by the University of British Columbia, a grantee of the Bill & Melinda Gates Foundation, through the PRE-EMPT initiative (grant number OPP1017337). Declaration of Interests: We declare no competing interests. Ethics Approval Statement: The CLIP trials were approved by the University of British Columbia Research Ethics Board as the Coordinating Centre (H12-03497) and within each country (MDC/IECHSR/2013-14/A, India; 2590-Obs-ERC13 Pakistan; 219/CNBS/13 Mozambique; OOUTH/DA.326/T/1/ Nigeria).