Research Commentary [8] July 2017

Jul 1, 2017

The theme of this review is “Stroke and Asian communities”.

ARCOS IV: Auckland Regional Community Outcomes of Stroke Study, is an epidemiological study of the determinants of stroke impact on individuals, families and communities, carried out in Auckland in 2002–2003 (Feigin et al., 2006). The study, which is ongoing found that compared to New Zealand Europeans, Maori, Pacific and Asian people are at 1.5 to 3 times’ greater risk of ischaemic stroke and intracerebral haemorrhage. The increased risk of stroke in Maori, Pacific and Asian people is partly attributed to a higher prevalence of obesity, diabetes and high blood pressure in these ethnic groups.

Stroke is a time-critical illness and faster diagnosis and treatment saves lives and the quality of life. At present not enough people in Asian communities recognise a stroke when it occurs and too few know how vital it is to call an ambulance. South-Asian adults (Indian, Fiji Indian, Sri Lankan, Afghani, Bangladeshi, Nepalese and Pakistani) aged 40-60 years are among the key audiences for the FAST campaign to encourage people to learn the signs of stroke and to ring 111. South Asian groups disproportionately affected by stroke. The campaign is delivered by the Ministry of Health, Stroke Foundation and the Health Promotion Agency.

It is critical that stroke is diagnosed and treated quickly as the effectiveness of many treatments is dependent on the time between onset of symptoms and intervention to minimise brain damage. The sooner stroke patients get to hospital the lower the likelihood that death or permanent disability will result. Time dependent treatments that reduce death and disability after stroke include:

  • access to stroke unit care in a hospital;

  • aspirin as soon as possible after ischaemic stroke; and

  • use of a tissue plasminogen activator (tPA), a thrombolytic or clot-busting drug, which must be administered within 4 hours after a stroke.

Failure to act when symptoms arise is the main factor behind stroke treatment delay. Many people are unable to act because they cannot recognise the symptoms of stroke when it occurs. The FAST test is an easy way to remember and recognise the signs of stroke and prompts people to call 111 immediately if they see any of the signs.

FAST stands for:

  • Face – Is their face drooping on one side?

  • Arm – Is one arm weak?

  • Speech – Is their speech jumbled, slurred or lost?

  • Time – Time to call 111.

Delayed recognition of a stroke means delayed intervention, which can have tragic consequences.

The CALD Older People Resource for Health Providers is intended to support the health and disability workforce to provide culturally competent care for older peoples from Asian, Middle Eastern and African backgrounds and their families. This culturally and linguistically diverse (CALD) older people resource has recently been updated and can be accessed here. The resource includes information on the cultural care of CALD Older People with stokes, and their families.

Reference:

Feigin, V., Carter, K., Hackett, M., Barber, P.A., McNaughton, H., Dyall, L., Chen, M-h. & Anderson, C. (2006). Ethnic disparities in incidence of stroke subtypes: Auckland Regional Community Stroke Study, 2002–2003. The Lancet Neurology, 5, (2), 130–139. Retrieved from: https://www.ncbi.nlm.nih.gov/pubmed/16426989

Commentary provided by Dr Annette Mortensen, eCALD® Project Manager: Research & Development

The following are articles reviewed:

Article 1: Are ethnic inequalities in 30-day ischaemic stroke survival emerging as treatment becomes more effective?

This retrospective cohort study documented a significant increase in ethnic inequalities in stroke in New Zealand. The study addresses the question of how do we explain the growing ethnic inequality in ischaemic stroke survival? Two possible explanations warrant consideration: that there are growing differences in severity at presentation that could be due either to differences in the type of stroke, or differences in health-seeking behaviour that make non-European ethnicities less likely to present with milder strokes; or that there are ethnic differences in access to and use of the increasingly life-saving hospital and/or community services for acute stroke patients.

Growing differences in severity at presentation should first be examined as a possible explanation for the increasing inequalities in stroke survival. If combined with age, severity at presentation accurately predicts survival and functional outcome from stroke. Failure of Māori, Pacific, and Asian people to obtain appropriate treatment in primary care for transient ischaemic attacks of very mild stroke might increase the probability of subsequent more severe strokes. Asians, but not Māori and Pacific people, are less likely to have visited a GP in the preceding 12 months than Europeans, but this statistic does not take into account the higher health needs of Māori and Pacific groups.

The other possibility is that improvements in care have reduced Case Fatality Rates (CFR) in Europeans, but not Māori and Pacific, because of differences in access and uptake of these services. Higher levels of health literacy may give Europeans advantages in attaining time-dependent services such as thrombolysis, and they may have shorter travelling times to the hospitals that provide these. Europeans may also have advantages in complying with treatments to avoid life-threatening complications from stroke (eg, fewer language barriers). Post-acute rehabilitative services may not adequately cater to cultural diversity, reducing their potential benefit to non-Europeans. There is evidence of ethnic inequalities in hospital care generally in New Zealand.

Based on these findings, we can no longer accept that ethnic-specific CFRs are similar for Europeans, Māori, Pacific, and Asians. Whether this is due to ethnic differences in severity at presentation, the type of stroke and the distribution of prognostic risk factors, or to differences in quality and uptake, acute care remains to be elucidated. If it is the latter, then we expect that socioeconomic and ethnic inequalities in ischaemic stroke CFRs will soon emerge in other countries, especially those with disparities in other health outcomes.

Authors: Sandiford, P., Selak, V. Ghafel, M.

Citation: Sandiford, P., Selak, V. Ghafel, M. (2016). Are ethnic inequalities in 30-day ischaemic stroke survival emerging as treatment becomes more effective? NZMJ, 129, (1437), 8-14.

Publication

Article 2: 30-year trends in stroke rates and outcome in Auckland, New Zealand (1981-2012): a multi-ethnic population-based series of studies. PLoS One.2015; 10:e0134609.

With regard to aetiological risk factors and type of stroke, ARCOS IV data have shown that the pattern of risk factors in stroke patients has changed significantly over time, but to varying extents for the different ethnicities. In 2011/12, compared with 2002/3, there was a substantial increase in the prevalence of smoking, but only among Pacific patients; hypertension prevalence rose in European and Asian patients, but not in Māori or Pacific; a history of myocardial infarction increased by about 50% in Māori, Pacific and Asian patients, but more than doubled in European; the prevalence of diabetes rose in European, Pacific and Asian patients, but fell among Māori; and atrial fibrillation increased significantly in Europeans, but not in other ethnicities. By 2011/12, Māori and Pacific patients had a much higher prevalence of smoking and diabetes, and a lower prevalence of prior myocardial infarction than European patients. There was also a higher prevalence of diabetes in Asian peoples.

Authors: Feigin VL, Krishnamurthi RV, Barker-Collo S, et al.

Citation: Feigin VL, Krishnamurthi RV, Barker-Collo S, et al. (2015). 30-year trends in stroke rates and outcome in Auckland, New Zealand (1981-2012): a multi-ethnic population-based series of studies. PLoS One. 2015; 10:e0134609.

Publication 

Article 3: Ethnic disparities in incidence of stroke subtypes: Auckland Regional Community Stroke Study, 2002–2003.

This study aimed to provide population-based data on the differences in the incidence of major pathological stroke types and ischaemic stroke subtypes across ethnic groups in Auckland. The study found that in NZ/European people, ischaemic stroke comprised 73%, primary intracerebral haemorrhage (PICH) 11%, and subarachnoid haemorrhage 6%, but PICH was higher in Maori/Pacific people (17%) and in Asian/other people (22%). Compared with NZ/European people, age-adjusted RRs for PICH were 2·7 (95% CI 1·8–4·0) and 2·3 (95% CI 1·4–3·7) among Maori/Pacific and Asian/other people, respectively. The corresponding RR for ischaemic stroke was greater for Maori/Pacific people (1·7 [95% CI 1·4–2·0]), particularly embolic stroke, and for Asian/other people (1·3 [95% CI 1·0–1·7]). The onset of stroke in Maori/Pacific and Asian/other people began at significantly younger ages (62 years and 64 years, respectively) than in NZ/Europeans (75 years; p<0·0001). There were ethnic differences in the risk factor profiles (such as age, sex, hypertension, cardiac disease, diabetes, hypercholesterolaemia, smoking status, overweight) for the stroke types and subtypes.

Compared to NZ/Europeans, Maori/Pacific and Asian/other people are at higher risk of ischaemic stroke and PICH, whereas similar rates of subarachnoid haemorrhage were evident across ethnic groups. The ethnic disparities in the rates of stroke types could be due to substantial differences found in risk factor profiles between ethnic groups. This information should be considered when planning prevention and stroke-care services in multi-ethnic communities.

Authors: Feigin, V., Carter, K., Hackett, M., Barber, P.A., McNaughton, H., Dyall, L., Chen, M-h. & Anderson, C.

Citation: Feigin, V., Carter, K., Hackett, M., Barber, P.A., McNaughton, H., Dyall, L., Chen, M-h. & Anderson, C. (2006). Ethnic disparities in incidence of stroke subtypes: Auckland Regional Community Stroke Study, 2002–2003. The Lancet Neurology, 5, (2), 130–139.

Publication

Article 4: "Natural" Care: The lived experience of European and Chinese family carers for their stroke impaired relatives in Auckland, New Zealand—A qualitative study.

Using stroke—a condition which often requires chronic disability management—as an example, this study aims to investigate the lived experiences of European and Chinese family carers living in Auckland. This was done through the examination of 1) the family carers’ role; 2) the impact of the carer role on the physical and psychological health of the family carers; 3) the family carers’ relation- ships with their immediate family members and the wider community; 4) cultural differences in knowledge, approach and utilisation of carer support services, and 5) the relationship of gender and family care-giving experiences.

The study offers insight into the informal care-giving phenomenon in Auckland from a service user’s perspective. The findings highlight differences in expectations between family carers and health services, leading to miscommunication and strain in service provider-service user relationship. The study also highlights changes in family carers’ service needs at different stages of the stroke management journey. Appropriate training and education is necessary immediately after stroke survivor’s discharge. Psychological support is most desired after the stroke survivors’ condition stabilises and carers re-engage with their personal lives. Chinese family carers require additional support interventions appropriate to the Chinese model of family care-giving.

Authors: Wong, C. W.

Citation: Wong, C. W. (2013). "Natural" Care: The lived experience of European and Chinese family carers for their stroke impaired relatives in Auckland, New Zealand—A qualitative study. The University of Auckland. Master of Public Health Thesis, Auckland: The University of Auckland.

Publication

Article 5: Epidemiology of stroke and its subtypes in Chinese vs white populations: a systematic review.

This is the first systematic review of the epidemiology of stroke and its pathologic types and ischemic subtypes comparing data from Chinese populations with data from predominantly white populations of European origin. The authors report a slightly higher overall stroke incidence and a higher proportion of intracerebral hemorrhage [ICH] in Chinese compared with white populations since 1990, with substantial regional variation among Chinese populations. These differences are based on comparisons of methodologically robust community-based studies, with appropriate age standardization, avoiding inclusion of an open-ended upper age band. Proposed explanations for Chinese-white differences and variation among Chinese populations in overall stroke incidence and in the proportion of ICH include differences in hypertension, hyperlipidaemia, diabetes, obesity, dietary habits (e.g., variable intake of salt and preserved food), smoking, extreme weather, socioeconomic status, and genetic factors. These vary substantially within Chinese populations as well as between Chinese and white populations.

Authors: Tsai, C.F., Thomas, B. & Sudlow, C.L.

Citation: Tsai, C.F., Thomas, B. & Sudlow, C.L. (2013). Epidemiology of stroke and its subtypes in Chinese vs white populations: a systematic review. Neurology, 81(3), 264-72.

Publication