Assessing knowledge of healthcare providers concerning cardiovascular risk after hypertensive disorders of pregnancy: an Australian national survey

Hypertensive disorders of pregnancy (HDP) includes preeclampsia (PE), gestational hypertension (GH) and pre-existing or chronic hypertension (CH) and complicates 5–10% of pregnancies [1]. PE is a multi-system disorder, characterised by hypertension and involvement of one or more other organ systems and/or the fetus [2, 3]. Gestational hypertension is new onset hypertension without any other complications during pregnancy and has little association with adverse pregnancy outcomes apart from increased risk of progression to preeclampsia [2, 3]. Both conditions are associated with long-term cardiovascular sequelae [4, 5]. Cardiovascular disease (CVD), the leading cause of death in women globally [6], is up to two and a half times higher for women after HDP versus those with no HDP [4, 5, 7, 8]. This increased risk remains after adjusting for the presence of other cardiovascular risk factors and is present within 5–10 years after the affected pregnancy [8‐12].

Both Australian and international societies, including the Society of Obstetric Medicine of Australia and New Zealand (SOMANZ) and the International Society for the Study of Hypertension in Pregnancy (ISSHP), recommend women and healthcare providers (HCP) are provided with information about HDP and later CVD, and HCPs should ask women about their HDP history when assessing cardiovascular health and risk factors. This includes review at 3 months postpartum and regular follow-up with a GP to monitor blood pressure, fasting lipids and blood sugar [2]. Recommendations emphasise adoption of a healthy lifestyle with maintenance of an ideal weight and regular aerobic exercise [2, 3]. Despite existing evidence and recommendations, it is unknown whether Australian HCPs are aware of the association between HDP and CVD [13]. The aim of this study was to explore Australian HCPs current knowledge and practice regarding long-term cardiovascular health after HDP, as a precursor to producing targeted HCP education on health after HDP.

A national, multidisciplinary survey of HCPs was conducted, using a custom-created, face-validated online survey (Additional file 1). Ethical approval was provided by South-Eastern Sydney Human Research Ethics Committee (Ref: 18/POWH/326).

In total, 573 survey responses were received (Fig. 1). Eighty-one were excluded: 48 for not answering the key inclusion question ‘Do you think that there is an increased risk of developing future cardiovascular disease after gestational hypertension or preeclampsia?’ and 33 for representing diverse professions that were not the target HCPs. Of 492 included responses 203 (41%) were from midwives, 75 (15%) GPs, 188 (38%) obstetrician/gynaecologists and 26 (5%) cardiologists. Of these, 446 provided responses to the detailed knowledge questions. Most respondents were female (82%) and approximately half had > 15 years’ experience in their profession, with the exception of cardiologists (70% 10 years or less in the profession). Almost all respondents (94%) see/treat women with a history of PE or GH, and the majority (78%) stated they routinely ask women about their pregnancy history including GH or PE (Table 1). Most respondents were aware of the increased CVD risk after both PE and GH (85%), while 6% thought only PE (4%) or GH (2%) increased risk, but not both (Table 2). The 9.3% who did not know (8.5%) or believed that neither GH nor PE (0.8%) carried a risk were directed to the end of the survey, with the remaining 446 respondents directed towards more in-depth knowledge questions.

Overall, most professions had ‘high’ knowledge with regards to women developing chronic hypertension after PE and GH (Table 3). Although ‘high’ knowledge was displayed for HDP recurrence after PE (‘moderate’ for midwives at 0.72, GP 0.84, obstetricians 0.90, cardiologists 0.96), more varied results were noted for recurrence of HDP after GH, ranging from ‘low’ for midwives, ‘moderate’ for GPs and obstetricians to ‘high’ for cardiologists. Lowest knowledge across all four professions regarded future diabetes risk for both PE (range midwives 0.30 to cardiologists 0.81) and GH (from midwives 0.25 to cardiologists 0.65). Another low scoring condition was peripheral vascular disease (PVD), where knowledge was ‘low’ to ‘moderate’ for both PE and GH. Additional file 2 shows the detailed breakdown of respondent answers, including proportion answering ‘I don’t know’ or skipping questions versus giving a firm but incorrect answer. Conditions with the highest proportion of “I don’t know” answers were diabetes, PVD, and the three distractors (breast cancer, leukaemia and seizures).

Overall average knowledge scores were ‘low’ for midwives (5.9 for PE and 5.1 for GH), ‘moderate’ for GPs (7.6 PE, 7.4 GH) and obstetricians (8.2 PE, 7.5 GH) and ‘high’ for cardiologists (9.3 PE and 9.0 GH). Only 34% were aware that the risks start to manifest less than 10 years after an affected pregnancy (Table 4). Regarding usual practice around risk discussion with women after HDP, the most frequent practices by all professions were assessing CVD risk (61%) and recommending lifestyle changes (66%) (Table 5).

In this novel Australian HCP survey, most respondents (85%) were aware that both GH and PE increase the long-term risk of CVD and ‘always’ (78%) ask about HDP history. Despite this reasonably high awareness of HDP being linked to future CVD risks, we identified significant knowledge gaps regarding individual conditions. All professions had consistently lower knowledge scores regarding conditions after GH. This may be because GH is seen as a more benign form of HDP, although studies show GH has similar CVD risk to preeclampsia [4, 14].

Within the context of the selected sample of HCPs, findings were expected to reflect a ‘best-case’ scenario of knowledge as their specialised training theoretically indicates high overall knowledge. Of the total respondent number (n = 573), 48 (8%) were excluded for not answering the key risk question asked (‘Do you think that there is an increased risk of developing future cardiovascular disease after gestational hypertension or preeclampsia?’) and 46 of the n = 492 respondents (9%) for being unsure or not believing there are health risks after HDP. Therefore, even in this sample, with sufficient interest in the topic to undertake the survey, a minority had very low or incorrect overall knowledge. Education developed will need to cater to HCPs with no pre-existing knowledge as well as focus on the specific gaps identified by the survey.

International studies exploring HCPs knowledge have reported overall low knowledge [13]. These studies feature results from highly specialised HCPs with substantial involvement in maternity and women’s health care. Only one study has examined knowledge of HCPs on long-term health risks after both PE and GH, whilst all others focus on risks after PE only [15]. In line with another study that found that higher knowledge was associated with belonging to a particular profession [16], we found higher knowledge among medical professionals compared with midwives. However, in contrast to an American study that found obstetricians generally had more awareness of CVD after PE than internal medicine physicians [17], cardiologists were the highest scoring profession in this survey, DRANZCOG GPs and obstetricians were quite similar.

This study identified some significant knowledge gaps amongst specialist HCPs. Our study findings resonate with those from similarly targeted HCPs in Canada, Germany, Nigeria and the USA conducted between 2007 and 2017 [13]. Therefore, from a global perspective, this reinforces the research to practice gap in yet another country a few years on. With international guidelines, including ISSHP 2018 [2], specifically targeted to assist HCPs on an international scale to better manage and address health after HDP, this practice gap would be expected to narrow.

Given the different scope of practice of various professions, different knowledge and knowledge gaps were expected, and our results can help tailor future education of different HCPs on this topic. For example, options might include improving knowledge about the risks associated with GH amongst specialist GPs and obstetricians. Once this educational material has been piloted with the specialised HCPs, it may be adapted to suit a broader distribution which would include, for example, GPs without specialist qualification in women’s health.

In this study, the condition following PE or GH associated with the highest knowledge was chronic hypertension, consistent with previous HCP studies [15‐18]. Knowledge was lowest with regards to PVD and diabetes across all groups. The wide range of knowledge levels displayed within this study concerning risk of recurring HDP was an unexpected finding and suggests further need for maternity care provider education on this topic.

Only one-third of respondents were aware that risks start to manifest under 10 years after an HDP pregnancy, which may negatively impact on timely follow up and counselling of affected women. In combination with predominantly low to moderate knowledge of most individual CVD conditions explored within this study, this suggests opportunities are currently being lost to discuss preventive strategies that could improve women’s health trajectories. The majority of participants were female. Given that midwifery is a predominantly female occupation in Australia, and GPs and obstetricians closer to 50:50, the response rate of male versus female within these three professions is not unexpected. However, given that a minority of Australian cardiologists are female, the high fraction of cardiology respondents being women suggests bias in this sample.

As with all surveys, it is uncertain how representative it is of the population under study i.e. it is unknown whether knowledge of non-respondents is comparable to that of respondents. Furthermore, the number of respondents in all included subgroups are a small proportion of the national registers (particularly cardiologists) which suggests volunteer bias and also affects generalisability. However, non-representative national HCP numbers along with a highly specialised sample of HCPs can be noted within all research addressing HCP knowledge [13]. This study was also subject to sample limitations as specialised maternity and women’s health HCPs with prior knowledge of the link between HDP and CVD were included in the analysis e.g. the targeting of GP distribution to DRANZCOG holders. This was, however, a deliberate decision, since it can reasonably be expected that these specialised GPs have highest, relative knowledge. Therefore, the knowledge gaps that were found can be expected to extend to the wider Australian GP population. In addition, we targeted these specialised GPs with awareness that response rates to GP surveys are generally very low. For example, recruited numbers were < 15% in this study despite various, targeted recruitment strategies in place [19]. A more general/inclusive spread of midwives, GPs, obstetricians would likely have lesser knowledge than our sample as fewer maternal health qualifications (GPs) and/or not be interested enough in the topic to take the survey. Therefore, when designing education it would be wise to cater for no higher than the levels of knowledge exhibited in our sample, and also cater for lower levels of knowledge.

Our custom-created knowledge score is both a strength, as it allows for a summary of findings across all the conditions and risks, and a limitation, as assigning cut-points is an arbitrary designation. Having included the distractor conditions (breast cancer, leukaemia and seizures) may also have altered the overall score. However, we believe it is important that knowledge is both of conditions that actually do occur more often after GH/PE, plus not incorrectly believing these women are at increased risk of more conditions than they are.

In our Australian survey of HCP knowledge of risks after HDP, we have found varying knowledge from the targeted professions. Despite ‘high’ knowledge being demonstrated in some areas, significant knowledge gaps were identified. These gaps with regards to general and specific disease risks for women post HDP are important in planning tailored education for HCPs. This may in turn assist in early identification of CVD risk factors in women with a history of HDP and improved subsequent counselling and management.