Introduction

Informed consent is “both an ethical obligation and a legal requirement spelled out in statutes and case law in all 50 states,” notes the American Medical Association. Along with the diagnosis, physicians are to detail the therapeutic route under consideration and alternatives—what these are, why they are used, the risks and benefits of each option. The risks and benefits of forgoing treatment should also be discussed. Patients then need a chance to ask questions. But how long do patients have to contemplate what they’ve been told, especially in emergent situations? Journal Club members discussed a new study that explored this question.

George A. Macones, MD, MSCE, Associate Editor

Introduction

Informed consent is “both an ethical obligation and a legal requirement spelled out in statutes and case law in all 50 states,” notes the American Medical Association. Along with the diagnosis, physicians are to detail the therapeutic route under consideration and alternatives—what these are, why they are used, the risks and benefits of each option. The risks and benefits of forgoing treatment should also be discussed. Patients then need a chance to ask questions. But how long do patients have to contemplate what they’ve been told, especially in emergent situations? Journal Club members discussed a new study that explored this question.

George A. Macones, MD, MSCE, Associate Editor

Background

Macones: Can you provide some background on this topic? Why did the authors choose to study consent times for cesarean delivery? Is this an important question? Why?

Zigler: The practice of informed consent contains ideals that date back to the Hippocratic Oath. It ensures that the patient understands an intervention, gives permission to perform said intervention, and has an alternative option. In order for a patient to fully understand a proposed treatment route, this process should not be rushed. Yet oftentimes, especially in emergent situations, it is rushed. This is the case for many cesarean deliveries. The question is important, as it is not ideal to hurry consent for a major surgery, especially when 2 lives are involved.

Study Design

Macones: What was the study design? How would you characterize the study population and study site? Please explain how the subjects were selected for inclusion and how the critical information for this study was obtained.

Trudell: This was a retrospective observational cohort study. Sixty three percent of the women in the study population were white, and the average age was 29 years. Notably, 52% had a body mass index that characterized them as obese; 31% were overweight. Compared to the general population, in which the Centers for Disease Control and Prevention reports birth rates are highest among women aged 24-29 years, the average age of this population was on the higher end, and I suspect that this may reflect that a majority of these pregnancies were planned.

The study site was an academic center with a moderate volume of 4,000 deliveries per year. From the author information, I believe the study was performed at the University of Michigan, although that is not directly stated in the paper. Unfortunately, there is no information on socioeconomic status or education level of the women; however, given the patient demographics and study site, I would guess that most of the women were insured and likely to be middle class, and I would hypothesize that most mothers had at least a high school education.

Subjects were drawn from the medical records of all cesarean deliveries performed in 2004. After excluding all scheduled cesarean deliveries, the authors then chose the first 100 cesarean deliveries performed for urgent indications. Nine of these deliveries were then excluded for missing or incomplete medical records. Another patient was excluded because she consented to cesarean section during a prenatal admission that took place prior to the start of labor. To obtain the time data most critical to the study question, the authors preferred to use the time documented on the consent forms. When the time was not provided on the consent form, the authors took the time associated with documentation of consent from nursing or physician labor notes, flow sheets, and operating room records.

Macones: What analytic approach was used? What exactly is Winsorizing?

Stuart: The analytic approach involved several standard statistical tests that ensured either the transformation of non-normally distributed variables or the use of the appropriate nonparametric test. In multivariate analysis, the authors included not only statistically significant variables from bivariate analysis, but also 4 variables (maternal age, race, parity, and obesity) that they and others might reasonably believe contributed to consent time. These 4 values provided face-validity; that is, they are examined because logically, they seem to be applicable, whether or not they ultimately prove to have a significant influence. Kaplan-Meier survival analysis was used to compare consent time between deliveries for fetal and other indications, as consent time was collected as a continuous variable.

Winsorizing is a process of altering the data to minimize the effect of extreme outliers so that standard statistical tests can still be used. In this study, consent times were Winsorized—all times below the 3rd percentile or above the 97th percentile were set to the 3rd and 97th percentiles, respectively.