Community-Level Compact City Design, Health Care Provision, and Outcomes of Patients With Stroke

Abstract

Background: The optimal scale of urbanization for stroke health care provision and the potential impact of compact city design on stroke outcomes remain unclear. We investigated the impact of zip code area-level compact city design using the walkability index (WI) and its mediators on stroke outcomes.

Methods: This nationwide retrospective study used data from patients with stroke from the J-ASPECT study (2017-2022). WI was calculated as the average of 3 Z-scored city design elements (population density, road connectivity, and variation in walkable facilities) from 113 1156 zip code areas in Japan. The association between WI and in-hospital mortality, functional independence at discharge, and medical costs was assessed using multivariable mixed-effects logistic regression model.

Results: Overall, 555 296 patients (median age, 75 [interquartile range, 66-83] years; female, 42.5%) from 818 hospitals were included. Higher WI was significantly associated with decreased in-hospital mortality (odds ratio [OR], 0.94 [95% CI, 0.92-0.96]) and increased functional independence (OR, 1.03 [95% CI, 1.02-1.04]). The highest WI group was associated with decreased mortality, primarily mediated by management in intensive or stroke care units (proportion mediated, 0.46 [95% CI, 0.35-0.63]), and the highest WI group was associated with increased functional independence, mediated by short road distance to the hospital (proportion mediated, 0.30 [95% CI, 0.21-0.44]).

Conclusions: Zip code area-level compact city design was associated with decreased in-hospital mortality and increased functional independence. Compact city design at community level, even without large-scale urbanization, may contribute to improving stroke care provision and outcomes in increasingly urbanized societies.

Keywords: city design; city environment; compact city; primary stroke center; stroke; urban; walkability.

Figure 1. Patient selection flow chart.

Emergency admission and admission within 3 days of stroke onset were included. Patients with missing zip code information, those who had lived in facilities, or those who were hospitalized just before admission were excluded. Those admitted to a prefecture distant from their zip code (not geographically adjacent) were also excluded.

Figure 2. Representative community categorized into first and fourth walkability index groups.

The variation of facility type is represented as 18 different colors. The community of the fourth WI group looks more intense with intersection dots and facility diamonds compared with the community of the first WI group. WI indicates walkability index.

Figure 3. Distribution of walkability index group and zip code area‐level representative points.

The representative points of all 113 156 zip code areas in Japan were assigned to WI and categorized into quartile groups by WI. The higher the WI area, the darker the color. WI indicates walkability index.

Figure 4. Odds ratio or percent change of the outcomes according to walkability index.

Model 1: Unadjusted using only municipalities as a random effect. Model 2: adjusted for age, female sex, premodified Rankin Scale score of 0 to 2, area deprivation index. Model 3 when in‐hospital mortality or functional independence was the outcome: adjusted for age, female sex, hypertension, diabetes, dyslipidemia, current/past smoker, stroke subtypes, consciousness level, premodified Rankin Scale score of 0 to 2, area deprivation index. Model 3 when medical costs was the outcome: adjusted for age, female sex, hypertension, diabetes, dyslipidemia, current/past smoker, stroke subtypes, consciousness level, premodified Rankin Scale score of 0 to 2, area deprivation index, and surgical and endovascular intervention. A, Analysis of in‐hospital mortality. B, Analysis of functional independence at discharge. C, Analysis of medical costs. Model 3 forest plots are shown on the right side. IQR indicates interquartile range; JPY, Japanese yen; mRS, modified Rankin Scale; OR, odds ratio; and WI, walkability index.

Figure 5. Mediation analyses for the association of the highest WI group with in‐hospital mortality and functional independence at discharge.

Adjusted for age, female sex, hypertension, diabetes, dyslipidemia, current/past smoker, stroke subtypes, consciousness level, premodified Rankin Scale score of 0 to 2, area deprivation index, the second WI group, and the third WI group. A, Mediation analyses for the association of the highest WI group with in‐hospital mortality compared with the lowest WI group in the quartile mediated by prehospital and hospital factors. B, Mediation analyses for the association of the highest WI group with functional independence at discharge compared with the lowest WI group in the quartile mediated by prehospital and hospital factors. A negative mediated proportion was considered as no mediation, as it was out of the threshold to determine a mediated proportion. int‐HP transfer indicates interhospital transfer; MT, mechanical thrombectomy; and PSC, primary stroke center.