Zanzibar Stroke Study: Narrowing the Gaps in Hypertension Care, and Improving Stroke Outcomes (ZanStroke)

Background:

A previous study in Zanzibar (which Jutta Adelin Jorgensen, PI of ZanStroke, led) showed a high prevalence of hypertension among adults at 33%, in fact higher than average in Sub-Saharan Africa (SSA), and poor performance of the health systems with nearly 90% of people with hypertension not achieving adequate blood pressure control. Uncontrolled hypertension (HTN) and stroke have already become among the commonest causes of admission to and death at hospital in Zanzibar. At the same time, there is little or no data available to quantify the stroke burden on types, treatment and outcomes, cost of stroke care, nor a comprehensive understanding of the causes of poor hypertension control in the population.The Tanzanian Stroke Incidence study (which Richard Walker from Newcastle University led) showed some of the highest stroke incidence rates in the world. However, there are many unanswered questions, and the Zanzibar Stroke Study will be a unique opportunity to look at all stroke admissions from a large island population.

Zanzibar Stroke Study:

The hypotheses investigated are

1a. Current challenges in stroke care cannot exclusively be explained by limited structural resources, and care delivering processes play an essential role.

1. b. Current organization and quality of care for stroke including rehabilitation could benefit from being aligned with best practices for low resource settings.
2. a. Stroke types, causes, and prognosis are dominated by a higher proportion of hemorrhagic strokes, associated to poorly controlled hypertension, higher 30-day mortality, and worse prognosis in terms of disability and mortality at 12 months than seen in high income settings.

2b Long term stroke outcome is not only depending on stroke severity but also on sociodemographic/economic factors with worse prognosis for the poorest part of the population.

3a. There is a significant first stage delay due to local perceptions and beliefs around stroke which prohibits biomedical treatment in the prognostically important acute phase of stroke 3b. There are untapped resources in the community that could be leveraged to increase adherence to medical treatment to control BP to prevent stroke and re-stroke, as well as making rehabilitation accessible 4a. Introducing a hypertension care package at lowest primary care level for people at high cardiovascular disease (CVD) risk to prevent stroke and re-stroke is cost-effective, affordable, and possible.

4b. With no intervention, the cost of stroke care at hospital level will in 10 years exceed the cost of all reproductive and child health (RCH) services.

ZanStroke is an observational, prospective study of stroke admissions to hospitals in Zanzibar (Unguja) enrolling all patients with a recent stroke (\< 30 days) over a period of one year to investigate the burden of stroke disease, risk factors and outcome up till 12 months post-stroke. This will be done through establishing a stroke patient register.

Participant data will include sociodemographic and -economic information, vascular risk factors and previous medical history, routine head-CT, routine biochemical results and other investigations, as well as early and long-term outcomes (deaths, disability, independence/functionality, quality of life, cognition, medicine adherence, rehabilitation therapy, re-stroke).

Approximately 80% of stroke patients in Unguja, Zanzibar who seek hospital care are admitted to the main hospital and the nearby private hospital, and these will undergo CT head scan, but this will not be possible in all of the other six hospitals. We will take blood samples and store serum and deoxyribonucleic acid (DNA) for potential future analysis from the main hospital and the nearby private hospital only.

In addition to the clinical epidemiological research, qualitative and health economic evaluation research will be undertaken to understand stroke patients and caretakers life worlds and perspectives, health care providers skills and practices, organization and processes of stroke care at hospital level, and to define a set of most cost-effective interventions to prevent and treat stroke in the particular Zanzibar context.

Current and future benefits and impacts:

With the demographic transition and population ageing in SSA rates of stroke are set to continue to increase rapidly as part of the double burden of disease (still a major burden of infectious diseases, as well as an unfinished agenda of maternal and newborn health).

Previous studies have already established a global high level of hypertension in the adult population in Zanzibar, and low performance of the health system for managing this.

It is important to identify the peculiar genomic, gene-environmental and environmental risk and protective factors for stroke occurrence, pattern, type, outcome, and current incidence velocity in SSA in order to inform preventive measures especially effective and cost-effective control of raised blood pressure/hypertension; the best model for the provision of inpatient care and rehabilitation in a resource poor environment with lack of access to dedicated stroke units and limited multidisciplinary team input; and to include the particular East Africa population in existing or future international stroke collaborations to ensure that genetic variations relevant to the population there are represented.

Eligibility Criteria:
Inclusion Criteria:

* admitted with a clinical diagnosis of stroke, or developing stroke while in hospital admitted for other cause (see below for stroke case definition)
* age above 18 year
* written consent form signed by patient, or authorized representative (spouse or caretaker)
* stroke onset \< 30 days when enrolled

Exclusion Criteria:

* patient or authorized representative unable to understand the information given or being interviewed.
* CT scan not suspect of stroke despite clinical suspect

Stroke case definition:

All the following stroke categories listed below that have been submitted as the most responsible diagnosis will be included in the stroke cohort. For patients developing stroke while admitted to hospital, stroke as the second diagnosis will also be included in the cohort. Patients who previously had a stroke and are being admitted due to complications, and where stroke is not the primary diagnosis during admission, will not be included in the cohort.

Definition of stroke ( ICD-10 classification code in parenthesis) that will be used in the study for inclusion in the cohort:

(a) Intracerebral hemorrhage (I61 including all sub-codes) (b) Ischemic stroke (I63 including all sub-codes, H34.1) (c) Stroke, not specified as hemorrhagic or ischemic (I64) (d) Cerebral Venous Thrombosis, non-pyogenic (I63.6) Where CTscan is not available, the clinical diagnosis of stroke will be used, and coding will be I64 (ICD-10)

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