Impact of areal socioeconomic status on prehospital delay of acute ischaemic stroke: retrospective cohort study from a prefecture-wide survey in Japan

Abstract

Objectives: To examine whether the Areal Deprivation Index (ADI), an indicator of the socioeconomic status of the community the patient resides in, is associated with delayed arrival at the hospital and poor outcomes in patients with acute ischaemic stroke from a prefecture-wide stroke database in Japan.

Design: Retrospective study.

Setting: Twenty-nine acute stroke hospitals in Kochi prefecture, Japan.

Participants: Nine thousand and six hundred fifty-one patients with acute ischaemic stroke who were urgently hospitalised, identified using the Kochi Acute Stroke Survey of Onset registry. Capital and non-capital areas were analysed separately.

Primary and secondary outcome measures: Prehospital delay defined as hospital arrival ≥4-hour after stroke onset, poor hospital outcomes (in-hospital mortality and discharge to a nursing facility) and the opportunities of intravenous recombinant tissue plasminogen activator (rt-PA) and endovascular reperfusion therapy.

Results: In the overall cohort, prehospital delay was observed in 6373 (66%) patients. Among individuals residing in non-capital areas, those living in municipalities with higher ADI (more deprived) carried a significantly higher risk of prehospital delay (per one-point increase, OR (95% CI) 1.45 (1.26 to 1.66)) by multivariable logistic regression analysis. In-hospital mortality (1.45 (1.02 to 2.06)), discharge to a nursing facility (1.31 (1.03 to 1.66)), and delayed candidate arrival ≥2-hour of intravenous rt-PA (2.04 (1.30 to 3.26)) and endovascular reperfusion therapy (2.27 (1.06 to 5.00)), were more likely to be observed in the deprived areas with higher ADI. In the capital areas, postal-code-ADI was not associated with prehospital delay (0.97 (0.66 to 1.41)).

Conclusions: Living in socioeconomically disadvantaged municipalities was associated with prehospital delays of acute ischaemic stroke in non-capital areas in Kochi prefecture, Japan. Poorer outcomes of those patients may be caused by delayed treatment of intravenous rt-PA and endovascular reperfusion therapy. Further studies are necessary to determine social risk factors in the capital areas.

Trial registration number: This article is linked to a clinical trial to UMIN000050189, No.: R000057166 and relates to its Result stage.

Keywords: PUBLIC HEALTH; SOCIAL MEDICINE; Stroke.

Figure 1

Distribution of population, acute stroke hospitals, ADI and prehospital delay in Kochi prefecture. (A) Distribution of the population of acute stroke hospitals in Kochi prefecture. Grey colouring shows the population distribution in a 1 km² basic mesh unit, where a darker mesh indicates a larger population (see LEGEND). Population mesh data were obtained from the Statistics Bureau of the Ministry of Internal Affairs and Communications of Japan (http://www.stat.go.jp/data/mesh/teikyo.html). The locations of all the acute stroke hospitals are indicated by the red circles. The area of the prefecture’s capital city is enclosed by the dotted line. (B) Location of municipalities according to ADI quartile. The capital city of Kochi Prefecture is indicated in black and is excluded from the non-capital area analyses. ADI, Areal Deprivation Index.

Figure 2

Flow diagram of patient selection from Kochi Acute Stroke Survey of Onset registry.