Hem 907xl device

Study coordinators (usually nurses or medical assistants) employed in each office enrolled patients and collected all baseline and subsequent data.^{17 (link)} Study coordinators where brought to Iowa City and trained by the investigators on human subjects and informed consent and all protocol procedures. Study coordinators were certified on proper blood pressure measurement technique using an automated Omron HEM 907-XL device.^{27 (link)} Blood pressure was measured three times in the sitting position after appropriate rest with arm resting on a table, feet flat on the floor and back supported. The patient and study coordinator were instructed not to talk during the measurements. The first blood pressure reading was not used and the second and third readings were averaged. If the second and third readings varied by more than 4 mm Hg (systolic or diastolic), a fourth measurement was taken and an average of the two closest readings was recorded. During initial intake, if blood pressure did not meet study inclusion criteria, the study coordinator informed the patient’s physician, and the patient was not enrolled. Study coordinators then collected medical and socio-demographic information from both the medical record and from the patient.

Clinic BP was measured by trained staff using a random zero sphygmomanometer (Hawksley and Sons Ltd., Lancing, UK) during the baseline study visit. Each participant’s right arm circumference was measured to determine the appropriate cuff size. After participants had rested for at least 5 minutes in an upright position with their back and arms supported, feet flat on the floor and legs uncrossed, two BP measurements in the right arm, separated by one minute, were recorded. The mean of these clinic BP measurements was calculated. Quality control was conducted by the JHS Coordinating Center by monitoring digit preference for each staff member and by comparing the mean BP level measured within and between study staff. A BP comparability substudy was conducted in which BP was measured simultaneously, using a Y connector, by random zero sphygmomanometer and an Omron HEM-907XL device, a semi-automated device. As described in the Supplement (see Methods and Supplemental Figure 1) and in prior analyses of the JHS, the random-zero BP measurements were calibrated to the semi-automated device using robust regression.^{13 (link),17 (link)} Elevated clinic BP was defined as mean clinic systolic BP (SBP) ≥ 140 mmHg or mean clinic diastolic BP (DBP) ≥ 90 mmHg.

Participating women underwent routine glycemic screening to identify disorders of glucose tolerance (mild hyperglycemia, GDM) between 24 and 28 weeks’ gestation (follow-up 1), as part of usual clinical care. Venous blood was sampled for glucose one hour after a 50-gram oral glucose load. If the glucose result was ≥130 mg/dL, the participant was referred for a 100-gram fasting 3-hour OGTT. Normal 3-hour OGTT glucose results include: < 95 mg/dL at baseline, < 180 mg/dL at 1 h, < 155 mg/dL at 2 h, and < 140 mg/dL at 3 h [72 (link)]. In this study, we define glucose intolerance in two ways: 1) 1-hour OGTT values ≥130 mg/dL (mild hyperglycemia), and 2) two or more abnormal values from the 3-hour OGTT (GDM). The small number of GDM cases in our sample precludes our ability to look at this outcome alone. Glucose values at a level of 130 mg/dL or higher are associated with adverse pregnancy outcomes [73 (link),74 (link)], and have been used by us and others to define milder states of glucose intolerance [75 (link),76 (link)]. Blood pressure was assessed by the OMRON HEM907XL device. Using methods identical to our prior studies [77 (link),78 (link)], two measurements (separated by 1-minute intervals after 5 min of sitting) were obtained at baseline and follow-up 2. We define hypertension as a mean systolic pressure > 140 mm/Hg or a mean diastolic pressure > 90 mm/Hg.