[59-OR] The control of hypertension in pregnancy study (CHIPS) randomized controlled trial – Is the type of antihypertensive important?

ObjectivesThe CHIPS Trial (ISRCTN 71416914, http://pre-empt.cfri.ca/CHIPS) randomized women with non-severe pregnancy hypertension to a diastolic blood pressure (dBP) target of 100mmHg [‘less tight’ (LT) control] vs. 85mmHg [‘tight’ (T) control]. LT was associated with no perinatal benefit, but more severe maternal hypertension. Labetalol was the recommended post-randomization antihypertensive. We aimed to: (1) determine whether the difference in outcomes between LT vs. T control depended on antihypertensive used; and (2) compare pregnancy outcomes, taking into account allocated group, between women taking methyldopa and those taking labetalol, the two most commonly used antihypertensives in CHIPS.MethodsLogistic regression was used for comparisons outlined in objectives (1) and (2). Both analyses adjusted for the influence of baseline factors, including use of any antihypertensive therapy at randomization.ResultsOf 987 women in CHIPS, labetalol (but not methyldopa) was taken by 433/837 women on antihypertensive therapy [186 (LT) vs. 247 (T)] and methyldopa (but not labetalol) by 223/837 [98 (LT) vs. 125 (T)]. Following adjustment: (1) ORs for outcomes in LT vs. T control were similar between antihypertensive groups, but (2) methyldopa use was associated with a reduction in some outcomes (Table). Additional sensitivity analyses had a trivial impact on results.ConclusionsIn this secondary analysis of CHIPS data, outcomes for LT vs. T control were not dependent on use of methyldopa or labetalol. The non-randomized comparisons between methyldopa and labetalol are subject to residual confounding, but there is no evidence that women treated with methyldopa (vs. labetalol) had inferior outcomes.DisclosuresL.A. Magee: Research Support Recipient; Commercial Interest: BMGF. P. von Dadelszen: Consultant, Commercial Interest: Alere International. E. Rey: None. S. Ross: None. E. Asztalos: None. K.E. Murphy: None. J. Menzies: None. J. Sanchez: None. J. Singer: None. A. Gafni: None. A. Gruslin: None. M. Helewa: None. E. Hutton: None. S.K. Lee: None. A.G. Logan: None. W. Ganzevoort: None. R. Welch: None. J.G. Thornton: None. J. Moutquin: None.