The generalizability of trial data; a comparison of beta-blocker trial participants with a prospective cohort of women taking beta-blockers in pregnancy

Estimation of Population Average Treatment Effects in the FIRST Trial: Application of a Propensity Score-Based Stratification Approach

OBJECTIVE/STUDY QUESTION

To estimate and compare sample average treatment effects (SATE) and population average treatment effects (PATE) of a resident duty hour policy change on patient and resident outcomes using data from the Flexibility in Duty Hour Requirements for Surgical Trainees Trial ("FIRST Trial").

DATA SOURCES/STUDY SETTING

Secondary data from the National Surgical Quality Improvement Program and the FIRST Trial (2014-2015).

STUDY DESIGN

The FIRST Trial was a cluster-randomized pragmatic noninferiority trial designed to evaluate the effects of a resident work hour policy change to permit greater flexibility in scheduling on patient and resident outcomes. We estimated hierarchical logistic regression models to estimate the SATE of a policy change on outcomes within an intent-to-treat framework. Propensity score-based poststratification was used to estimate PATE.

DATA COLLECTION/EXTRACTION METHODS

This study was a secondary analysis of previously collected data.

PRINCIPAL FINDINGS

Although SATE estimates suggested noninferiority of outcomes under flexible duty hour policy versus standard policy, the noninferiority of a policy change was inconclusively noninferior based on PATE estimates due to imprecision.

CONCLUSIONS

Propensity score-based poststratification can be valuable tools to address trial generalizability but may yield imprecise estimates of PATE when sparse strata exist.

Use and impact of cardiac medication during pregnancy

ABSTRACT 

Cardiovascular disease is the most encountered cause of maternal death during pregnancy in the western world and an increase in maternal mortality due to cardiac causes has been observed. More women with congenital or acquired heart disease have the desire to become pregnant. Pregnancy is known to impose a major hemodynamic burden and also has impacts on the coagulation system. The risk of developing complications is clearly increased as compared with the normal population. For optimal management, it is crucial to have information on the effects of cardiac medications on the fetus. The focus of this article is to discuss the management of cardiac disease in pregnancy, as well as the known safety of cardiac medications for the mother and/or fetus.

Antihypertensive drugs in pregnancy

Blood pressure targets and medications that are safe differ in pregnant women compared with nonpregnant individuals. The principles of treatment for mild, moderate, and severe hypertension in pregnancy, chronic versus gestational versus preeclampsia, and women hypertensive at term versus remote from term are reviewed. The choice of antihypertensive drugs also is discussed; methyldopa, labetalol, and nifedipine, among others, appear safe for use in pregnancy, whereas angiotensin converting enzyme inhibitors and angiotensin receptor blockers should be avoided. The management of increased blood pressure in the postpartum period, and agents to use in lactation, are also discussed.

A review of the methodological features of systematic reviews in maternal medicine

BACKGROUND

In maternal medicine, research evidence is scattered making it difficult to access information for clinical decision making. Systematic reviews of good methodological quality are essential to provide valid inferences and to produce usable evidence summaries to guide management. This review assesses the methodological features of existing systematic reviews in maternal medicine, comparing Cochrane and non-Cochrane reviews in maternal medicine.

METHODS

Medline, Embase, Database of Reviews of Effectiveness (DARE) and Cochrane Database of Systematic Reviews (CDSR) were searched for relevant reviews published between 2001 and 2006. We selected those reviews in which a minimum of two databases were searched and the primary outcome was related to the maternal condition. The selected reviews were assessed for information on framing of question, literature search and methods of review.

RESULTS

Out of 2846 citations, 68 reviews were selected. Among these, 39 (57%) were Cochrane reviews. Most of the reviews (50/68, 74%) evaluated therapeutic interventions. Overall, 54/68 (79%) addressed a focussed question. Although 64/68 (94%) reviews had a detailed search description, only 17/68 (25%) searched without language restriction. 32/68 (47%) attempted to include unpublished data and 11/68 (16%) assessed for the risk of missing studies quantitatively. The reviews had deficiencies in the assessment of validity of studies and exploration for heterogeneity. When compared to Cochrane reviews, other reviews were significantly inferior in specifying questions (OR 20.3, 95% CI 1.1-381.3, p = 0.04), framing focussed questions (OR 30.9, 95% CI 3.7- 256.2, p = 0.001), use of unpublished data (OR 5.6, 95% CI 1.9-16.4, p = 0.002), assessment for heterogeneity (OR 38.1, 95%CI 2.1, 688.2, p = 0.01) and use of meta-analyses (OR 3.7, 95% CI 1.3-10.8, p = 0.02).

CONCLUSION

This study identifies areas which have a strong influence on maternal morbidity and mortality but lack good quality systematic reviews. Overall quality of the existing systematic reviews was variable. Cochrane reviews were of better quality as compared to other reviews. There is a need for good quality systematic reviews to inform practice in maternal medicine.

Pharmacologic treatment of hypertensive disorders during pregnancy

Pregnancy complicated by hypertension is a common problem faced by clinicians. It can lead to substantial maternal and/or fetal/neonatal morbidity and mortality. There are a variety of medications that can be used during pregnancy either for treatment of significant chronic hypertension or in cases of acute severe hypertension. Most antihypertensive drugs have been shown to be safe for use in pregnancy. A variety of medications are available to treat more severe hypertension, although the use of pharmacologic therapy to treat mild chronic hypertension during pregnancy has not been supported in the literature. The data are more limited concerning drugs that would be used in the event of hypertensive emergencies or in an intensive care setting; however, in such a situation, maternal health and life become paramount and, despite lack of good studies, appropriate treatment should be rendered.

The safety of antihypertensives for treatment of pregnancy hypertension

This review addresses the maternal and perinatal benefits and risks of antihypertensive therapy in pregnancy. It covers the diagnosis of hypertension in pregnancy (with a brief discussion of ambulatory blood pressure measurement) followed by both the general principles of management of pregnancy hypertension and the specifics of individual antihypertensive drugs and drug classes. Discussion is focused on quantitative overviews of randomised, controlled trials, although observational literature is also discussed, particularly in reference to the potential teratogenicity of agents and the safety of their administration to nursing mothers. The treatment of severe hypertension is addressed separately from the treatment of mild-to-moderate hypertension, for which the maternal and fetal risks are substantially different.

The effect of antihypertensive drugs on the fetus

A critical review of the literature on the effects of antihypertensive drugs on the fetus in pregnant women is presented. The survey covers the alpha-adrenergic receptor agonists, beta-blockers including topical eye medications, alpha-beta blockers, calcium antagonists, diuretics, and angiotensin-converting enzyme (ACE) inhibitors. The lack of data on angiotensin II receptor blockers is noted although effects are considered to be similar to those reported with ACE inhibitors and therefore to be avoided. Analysis of the literature underscores that some antihypertensive drugs can be used safely at certain stages of pregnancy, while others are suspect and to be avoided at all costs. The lack of placebo-controlled studies on the treatment of severe hypertension in pregnancy due to ethical considerations is discussed against the background of the pressing need to treat these women despite the possible deleterious effects of antihypertensive drugs.