The epidemiology of peripartum cardiomyopathy in Scotland from 1998-2017

Jackson, Alice Maria (2023) The epidemiology of peripartum cardiomyopathy in Scotland from 1998-2017. PhD thesis, University of Glasgow.

Abstract

Background:
Peripartum cardiomyopathy (PPCM) is a type of heart failure, secondary to left ventricular systolic dysfunction, that develops around the time of pregnancy. The incidence of PPCM and its outcomes vary markedly between countries. There are few reports of the epidemiology of PPCM in Europe and none from the United Kingdom (UK). Extrapolation of existing data to the UK is limited by geographical and racial variation. It is likely that true regional variation does exist, but it is equally as likely that some of the differences in incidence and outcomes seen are explained by inconsistencies in the data sources, definition of PPCM, inclusion criteria, and applied methodology across studies. There are also large gaps in our understanding of long-term outcomes for women with the condition and for their babies.

Aim:
To describe the epidemiology of PPCM in Scotland, with a focus on incidence, factors associated with the development of the condition, long term outcomes, subsequent pregnancies and outcomes for children.

Methods:
I performed a retrospective, observational, population-level study of consecutive women hospitalised with incident PPCM using linked, national, administrative data, supplemented by data I collected directly from patients records throughout Scotland. Possible cases of PPCM were defined as woman with a discharge diagnosis of PPCM, heart failure or cardiomyopathy up to 6 months prior to or 2 years following a pregnancy outcome from 1998-2017 in Scotland. I reviewed case records to validate (or refute) the diagnosis of PPCM using the following criteria: impaired LV systolic function (left ventricular ejection fraction on transthoracic echocardiography of ≤50% or a qualitative assessment reporting left ventricular systolic dysfunction if no ejection fraction available), no clear alternative cause for left ventricular systolic dysfunction, no pre-existing diagnosis of left ventricular systolic dysfunction or cardiomyopathy, and diagnosis during pregnancy (excluding the first trimester) or up to 2 years postpartum. Each case was matched to 10 controls.

Data on demographics, comorbidities, socioeconomic status, clinical data (including laboratory tests, electrocardiographic and echocardiographic data), obstetric data and neonatal data were merged. I examined the following outcomes: death (all-cause, CV); rehospitalisation (all-cause, CV); a composite of death or rehospitalisation (all-cause, CV); total (recurrent) hospitalisations; a composite of CV death, intra-aortic balloon pump, ventricular assist device, extracorporeal membrane oxygenation or cardiac transplantation; stroke or thromboembolism; implantation of a cardiac device; LV recovery; and LV decline after recovery. Outcomes relating to a subsequent pregnancy were also examined. Neonatal outcomes, disease incidence, hospitalisation (any cause), total (recurrent) hospitalisations and death (any cause) were analysed in children born to women with PPCM.

Results:
The incidence of PPCM in Scotland over a 20-year period was 1 in 4950 deliveries and was similar in England at 1 in 4717. In Scotland, the incidence of PPCM was greater in women over the age of 32 years than in those aged 32 years or less. Among 225 women with PPCM (and 2240 matched controls), obesity, gestational hypertensive disorders, multiparity and multiple gestation were independently associated with the development of PPCM. Socioeconomic deprivation was also relevant, although this appeared to be explained by other baseline factors studied.

Over a median follow-up of 8.3 years/1,911 person-years for 221 women with PPCM (9.7 years/2024 person-years for echocardiographic outcomes), 8% of women died, 40% were rehospitalised at least once for a CV cause and 23% had at least two further CV hospitalisations (i.e. recurrent hospitalisations). The rates of death from any cause and of CV death or CV rehospitalisation in women with PPCM were approximately 12 – and 14-times that of controls, respectively. Complete LV recovery occurred in 76% of women throughout the whole study period (47% within 1 year), and, of those who recovered, 13% had sustained decline of LV systolic function despite initial recovery, at a median of 2.9 years after recovery.

A total of 36/225 (16%) women with PPCM had a subsequent pregnancy; these women were younger and more socioeconomically deprived than those without a subsequent pregnancy. The rate of all-cause death or all-cause rehospitalisation was similar in women with PPCM irrespective of whether or not they went on to have a subsequent pregnancy. Although 15% of women had a CV hospitalisation in the 1st year after the subsequent pregnancy, no women had a CV death or required mechanical circulatory support or cardiac transplantation up to 5 years after a subsequent pregnancy.

Over a median follow-up 8.8 years/1946 person-years for children born to women with PPCM, approximately 1 in 3 had an adverse neonatal outcome, with 4% case-fatality (including stillbirths) and a mortality rate approximately 5-times that of children born to controls. Children born to women with PPCM also had an approximately 3-times greater incidence of CV disease than children born to controls.

Conclusion:
PPCM affects 1 in 4950 women around the time of pregnancy. A number of factors were associated with the development of the condition in this population, including obesity, pregnancy-induced hypertension, pre-eclampsia and multiple gestation. Overall, 8% of women with PPCM died and 76% had recovery of cardiac function, but 13% of those who recovered had a sustained decline in LVEF after initial recovery. Outcomes were worse for women with PPCM than for controls. Adverse neonatal outcomes were more frequent, rates of all-cause mortality greater, and incident CV disease more common in children born to women with PPCM than in those born to controls. These findings suggest that PPCM is associated with considerable morbidity and mortality, both for the mother and the child.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Subjects: R Medicine > R Medicine (General)
• Colleges/Schools: College of Medical Veterinary and Life Sciences > School of Cardiovascular & Metabolic Health
• Funder's Name: British Heart Foundation (BHF)
• Supervisor's Name: Jhund, Prof. Pardeep and Petrie, Prof. Mark
• Date of Award: 2023
• Depositing User: Theses Team
• Unique ID: glathesis:2023-83467
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 03 Mar 2023 15:50
• Last Modified: 20 Feb 2024 11:09
• Thesis DOI: 10.5525/gla.thesis.83467
• URI: https://theses.gla.ac.uk/id/eprint/83467

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