Home blood-pressure monitoring in a hypertensive pregnant population: cost minimisation study: Cost of home blood-pressure monitoring in pregnancy

Background: Traditional monitoring of blood pressure in hypertensive pregnant women requires frequent visits to the maternity outpatient services. Home blood-pressure monitoring (HBPM) could offer a cost-saving alternative that is acceptable to patients. The main objective of this study was to undertake a health economic analysis of HBPM compared with traditional monitoring in hypertensive pregnant women. Methods: This was a case–control study. Cases were pregnant women with hypertension who had HBPM with or without the adjunct of a smartphone app, via a specially designed pathway. The control group were managed as per existing hospital guidelines. Specific outcome measures were the number of outpatient visits, inpatient bed stays and investigations performed. Maternal, fetal and neonatal adverse outcomes were also recorded. Health economic analysis was performed using two methods: direct cost comparison of the study dataset and process scenario modelling. Results: There were 108 women in the HBPM group, of whom 29 recorded their results on the smartphone app (App-HBPM) and 79 in their notes (Non-app HBPM). The control group comprised of 58 patients. There were significantly more women with chronic hypertension in This article is protected by copyright. All rights reserved. This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1002/uog.19041 A cc ep te d A rti cl e the HBPM group (49.1% vs 25.9%, P = 0.004). The HBPM group had significantly longer duration of monitoring (9 weeks vs 5 weeks P = 0.004) and started monitoring from an earlier gestation (30 weeks vs 33.6 weeks, P = 0.001). Despite these differences, the mean saving per week for HBPM compared with the control group was £200.69. For the App-HBPM cohort, the saving per week compared with the control group was £286.53. The process modelling method predicted savings of between £98.32 and £245.80 per week using HBPM compared to the traditional monitoring. Conclusion: HBPM in hypertensive pregnancies appears to be cost-saving compared with traditional monitoring, without compromising maternal, fetal or neonatal safety. Larger studies are required to confirm these findings. This article is protected by copyright. All rights reserved. A cc ep te d A rti cl e INTRODUCTION Hypertensive disorders such as gestational hypertension (GH), chronic hypertension and pre-eclampsia (PE) complicate up to 10% of pregnancies. The incidence of PE is 2–8%. While maternal mortality due to PE is decreasing in the UK, it remains a leading cause of direct maternal deaths worldwide as well as causing maternal, fetal and neonatal morbidity. The most recent ‘Mothers and Babies: Reducing Risk through Audits and Confidential Enquiries across the UK’ (MBRRACE-UK) report made several recommendations, including the need for an increased schedule of checks for hypertensive women and the need for prompt control of hypertension. Current care for women who develop hypertensive disorders of pregnancy centres on outpatient attendance to a day assessment unit (DAU) at their maternity hospital for bloodpressure monitoring and urine testing, as well as blood tests and fetal monitoring (cardiotocography and/or ultrasound scan), if indicated. The frequency of visits depends on the underlying diagnosis but is often two to three times a week. Admission to an antenatal ward is common place when initiating medication for uncontrolled blood pressure or if there is suspicion of PE. This frequent monitoring can represent a source of anxiety to these women and their families, it is demanding for them in terms of time, transport costs and work absence, and has significant cost implications for limited healthcare resources. Home blood-pressure monitoring (HBPM) is used extensively outside of pregnancy and is an accurate and patient-acceptable alternative to clinic visits. HBPM is recommended by the ‘British Hypertension Society’ and ‘National Institute for Health Research’ who have produced evidence to support its implementation. They advise that more research is needed into HBPM in pregnancy which reflects the need for this innovation to be transferred to the obstetric setting. The American College of obstetricians and Gynaecologists advocates the use of HBPM in patients with chronic hypertension and other professional bodies recognise its potential. HBPM is acceptable to pregnant patients and does not increase anxiety. The main objective of this study was to undertake a health economic analysis of the costeffectiveness of HBPM compared with traditional monitoring in hypertensive pregnancies. This article is protected by copyright. All rights reserved. A cc ep te d A rti cl e METHODS Population and Study Design This was a cost-minimisation study involving a cohort of hypertensive pregnant women enrolled on a HBPM pathway and a control group managed according to the traditional pathway of regular DAU visits for blood-pressure monitoring. Since the patients presented equivalent health outcomes and the main aim of the study was to assess cost savings of the new pathway compared with the conventional one, we called this study a cost-minimisation study. The study perspective was the direct costs to the healthcare system. Patients presented either via referral to the Hypertension Clinic or to the DAU at St George’s University Hospital NHS Foundation Trust between December 2013 and November 2016. Pregnant women with a history of pre-pregnancy hypertension or at increased risk of developing hypertension in pregnancy, systolic blood pressure ≥140mmHg, diastolic blood pressure ≥90mmHg, proteinuria ≤1+ on urine dipstick, normal full blood count, liver and renal function blood tests, English speaking were included in the study. Exclusion criteria were maternal age <16 years at booking, systolic blood pressure >155mmHg, diastolic blood pressure >100mmHg, proteinuria ≥2+ on urine dipstick, severe pre-eclampsia, intrauterine fetal growth restriction, significant mental health concerns, inability to give valid consent or language barrier. The above blood pressure parameters were selected in order to avoid patients developing severe hypertension at home. This is in line with the recommendation of hospital admission for systolic blood pressure of 160mmHg or diastolic blood pressure of 110mmHg. Severe PE was diagnosed in the presence of oliguria of less than 500mL urine output in 24 h, cerebral or visual disturbance, pulmonary oedema, epigastric or right upper quadrant pain, impaired liver function (twice the upper limit of normal levels for AST and/or ALT), thrombocytopenia (platelet count < 100,000/mm). The diagnosis of PE and GH was made according to the criteria of the International Society for the Study of Hypertension in Pregnancy. GH was diagnosed in the presence of systolic blood pressure ≥ 140mmHg and/or the diastolic blood pressure ≥ 90mmHg on at least two occasions 4 h apart developing after 20 weeks of gestation in previously normotensive women in the absence of significant proteinuria. In PE there should be GH with proteinuria of 300mg or more in 24 h, or two readings of at least ++ on dipstick analysis of midstream or catheter urine specimens if no 24-h collection is available. PE superimposed on chronic hypertension was diagnosed if significant proteinuria (as defined above) developed after 20 weeks of gestation in women with known chronic hypertension (history of hypertension before conception or presence of hypertension at the booking visit before 20 weeks of gestation in the absence of trophoblastic disease). The diagnosis of chronic hypertension was made when there was a documented presence of chronic non-GH prior to this pregnancy, or history of anti-hypertensive medication prior to 20+0 weeks. The diagnosis of White-coat Hypertension was made when there were confirmed high blood-pressure recordings in the hospital/clinic with normal readings on HBPM or ambulatory monitoring. Home blood-pressure monitoring pathway Women eligible to the home monitoring of pregnancy hypertension pathway were counselled and trained by a specialist midwife and supplied with an automated Microlife blood-pressure machine (MicrolifeCorporation, Taipei, Taiwan), which has been validated in pregnancy and PE, and with urine dipsticks. They were taught how to measure their blood pressure accurately and record readings in their notes or on a specially designed smartphone app (Hampton Medical, Trakka Medical, UK). Women were given a personalized schedule of monitoring based on their underlying diagnosis, which was reviewed by the midwife every 1– 2 weeks. While the schedule varied between patients, the frequency of monitoring complied This article is protected by copyright. All rights reserved. A cc ep te d A rti cl e with National Institute for Health and Care Excellence (NICE) guidance on hypertension in pregnancy. A typical regime for a woman with well-controlled chronic hypertension would be to measure blood pressure two or three times a week and be reviewed every 2–3 weeks, whereas a woman initiating new treatment would be asked to measure blood pressure twice a day and reviewed 1 week later. The same specialist midwife reviewed patients at the interim visits to reduce bias. The innovative application (App) for smartphone users was developed to enable women to record their blood pressure and urinalysis results and any symptoms at home. The App has a set of trigger questions to determine whether they are developing PE, such as the presence of headache, epigastric pain or visual symptoms. An alert flashes up on the screen if one of the trigger questions have indicated that the woman might be developing PE or the recorded blood pressure or urine results are above the pre-defined thresholds, advising the w