Hypertension (HTN) is a leading cause of cardiovascular diseases (CVD) and deaths globally [1]. An estimated 1.28 billion adults aged 30–79 years live with HTN globally, with two-thirds living in low- and middle-income countries [2]. It is a rising problem in many low- and middle-income countries [3], including Cambodia. The prevalence of HTN among adults aged 40–69 years in Cambodia was 23.5% in 2016 [4].
In response to this high prevalence, Cambodia has been re-organizing its health system to play an essential role in ensuring the effective management of HTN. In 2007, the government included management of HTN as basic care in the minimum package of activities by enabling primary care level facilities, such as health centers (HCs), to treat mild HTN and refer severe and complicated cases to district referral hospitals (RHs) [5]. Through support from the government and donor organizations, additional and innovative interventions for HTN and other non-communicable diseases, especially diabetes, have been introduced at different levels in the public health system and community in selected provinces. These include the following interventions: (1) the establishment of Non-Communicable Disease (NCD) clinics at the RHs, (2) the introduction of the World Health Organization Package of Essential Non-Communicable Disease Interventions (WHO PEN) program in HCs, and (3) the expansion and integration of the community-based MoPoTsyo’s Peer Educator Network.
NCD clinics have been established by the Ministry of Health (MoH) to provide hospital-based care for NCDs at RHs since 2007 with the aim of providing care for people with type 2 diabetes (T2D) and/or HTN through screening, diagnosis, treatment, and health education. Currently, 31 clinics are functional in selected operational districts (ODs) in 17 provinces. With regard to HTN, the NCD clinics offer consultation and treatment services to people living in the area.
The WHO PEN program has been implemented as health center-based care since 2015. This intervention aims to complement the function of the NCD clinics through screening suspected T2D and HTN cases. With regard to HTN, WHO PEN provides counseling, screening, and treatment for mild cases of HTN, and follow-up treatment for referred HTN patients at the HC level. The WHO PEN program has encouraged CVD risk screening, including blood pressure (BP) measurement, for adults aged 40 years and older. It is supported by the WHO and other non-government organizations [6]. As of February 2021, it covered 121 HCs. The activities mentioned in the WHO PEN comply with the new Minimum Package of Activities of the MoH, which allowed the treatment for mild HTN at HCs and referred severe and complicated HTN to RHs [7].
The MoPoTsyo Peer Educator Network, established and supported by a local non-government organization, provides community-based care and support for people with T2D and HTN. In the network, peer educators who are diabetic patients themselves, after being trained by the organization, provide regular follow-up checks and counseling to other patients registered in the network and assist them in getting access to medical services at RHs. With regard to HTN, peer educator networks also organize (1) community-based screening, (2) self-management support, (3) medication supply under a revolving drug fund, and (4) service operation through public facilities. MoPoTsyo is active in 20 districts in 8 provinces [8, 9].
While the interventions above take place at public health facilities, it must be noted that a significant proportion of the population does not use public healthcare [10]. Private facilities have been the primary choice of care for Cambodians when they get sick or injured; evidently, more than 70% of all healthcare visits took place at private healthcare providers in 2016 [11]. Furthermore, a majority (59%) of people with chronic diseases were diagnosed and treated in private facilities [12].
A multitude of interventions exists at both public and private facilities to diagnose and treat HTN in Cambodia, including the aforementioned innovative interventions in the public sector. However, little is known about the outcomes of these interventions. Studying the outcomes of a chronic condition such as HTN is complex since effective care for HTN requires a continuum of care (prevalence, screening, diagnosis, treatment, follow-up treatment, and control of HTN). An adverse health outcome at the end can be caused by a health system weakness at any of these steps. Therefore, applying a Cascade of Care (CoC) approach is critical to assess these outcomes. A CoC is a model to outline the sequential stage of long-term care (prevalence, screening, diagnosis, treatment, follow-up treatment, and control) required to achieve a desirable outcome. From a healthcare system perspective, a CoC model is a very useful tool for understanding where the health system has failed, to quantify losses and identify the characteristics of people lost in each stage of the care continuum.
A first but not comprehensive attempt to assess a cascade of HTN care was made through the national STEPS survey in 2016. This survey showed that, among respondents aged 18–69 years, 12.9% had their BP measured and were diagnosed with HTN. Of these, 32.7% were then taking prescribed medication, while only 16.1% of those on medication had their BP controlled [4]. The 2016 STEPS survey, however, produced the CoC for the population aged 18–69 years, rendering these results less useful to assess outcomes of the health system interventions that targeted the at-risk population. The healthcare guidelines on screening and treatment defined those aged 40 years or older as the ‘at-risk population’. In addition, the 2016 STEPS survey also did not collect additional information on the healthcare use related to HTN from one of the above-cited health system interventions. These limitations render additional up-to-date research on the at-risk population, their healthcare use, and resulting health outcome.
To better understand the effects of the above-cited health system interventions, it is also relevant to look at patient-related factors that influence the outcomes of HTN care. Socio-demographic and economic characteristics, for instance, might impact access to screening, diagnosis, or treatment, and consequently health outcomes in different ways. The influence of such factors on different steps in the cascade is not well documented and might be context-specific. Previous studies using the CoC approach have been previously published in the USA [13, 14], Brazil [15], and other Asian countries including India, China, Malaysia, and Laos [16–20], stressing the need for context-specific research in Cambodia.
This study aims to build an extended cascade of HTN care in Cambodia and explore the demographic characteristics explaining the ‘drop-out’ in the CoC. The extended cascade is composed of six bars: prevalence (i), screening (ii), diagnosis (iii), treatment in the last 12 months (iv), treatment in the last three months (v), and being under control (vi). The analysis will inform policymakers about the health system’s performance and differences in risk characteristics across the continuum of HTN care. Additionally, it will provide insights into the reasons for inequities in access and outcomes.