Spatial clusters with high mortality rates for chronic obstructive pulmonary disease among municipalities in Japan between 2017 and 2021: a flexible spatial scan statistics approach.

Chronic obstructive pulmonary disease is one of the leading causes of death worldwide and in Japan. This study aimed to detect the location and area of spatial clusters with high chronic obstructive pulmonary disease mortality rates in Japan during 2017-2021. Age-standardized numbers of expected chronic obstructive pulmonary disease deaths by sex and municipality were estimated from publicly available data from 1,895 municipalities in Japan. We performed flexible spatial scan statistics to detect the clusters with significantly high risk of chronic obstructive pulmonary disease death using the expected and observed cumulative mortality. During 2017-2021, the cumulative expected number of chronic obstructive pulmonary disease deaths was 87,450 (72,551 males and 14,899 females). There were 23 significant spatial clusters for males and 14 for females. The 23 clusters were scattered in 251 municipalities of 27 prefectures for males, while the 14 clusters for females were localized in 105 municipalities of 12 prefectures. The primary cluster for both sexes was detected in the Osaka Prefecture (males: log-likelihood ratio [LLR] = 188.23, relative risk [RR] = 1.46, p = 0.001; females: LLR = 106.42, RR = 1.95, p = 0.001). We found 23 significant spatial clusters for males and 14 for females. There were obvious sex differences in the distribution of the clusters. Our findings provide supporting evidence to discuss the prioritized areas in the allocation of health care resources to prevent and control the deaths associated with chronic obstructive pulmonary disease.