Regional Disparities in Incidence, Therapeutic Approaches, and In-hospital Mortality of Critical Limb Ischemia in Japan

Abstract

Aim: This study investigated regional disparities in the incidence, management, and in-hospital outcomes of critical limb ischemia (CLI) in Japan to inform standardized care practices. Methods: We conducted a retrospective cohort study using the nationwide Diagnosis Procedure Combination database, including patients ≥ 18 years old who were discharged from acute-care hospitals between April 2018 and March 2020. Patients with CLI were identified using ICD-10 codes and restricted to those undergoing invasive treatments including endovascular therapy (EVT), bypass surgery, or amputation. Regional differences in patient demographics, in-hospital management, and outcomes were analyzed across seven regions in Japan. Results: In total, 19,699 records were identified. CLI admissions per million population were highest in the Kyushu region (112.1) and lowest in the Kanto region (59.9). The proportion of patients with a body mass index (BMI) ＜18.5 kg/m2 ranged from 17.8% (Kanto) to 23.9% (Kansai), while the proportion with a BMI ≥ 30.0 kg/m2 ranged from 3.3% (Kyushu) to 8.2% (Okinawa). The proportion of patients requiring dialysis ranged from 33.8% in the Chugoku-Shikoku region to 38.2% in the Okinawa region (P = 0.005). Anti-platelet agents were prescribed to 82.1% of patients with CLI, whereas statins were prescribed to 36.1% of patients. The EVT rates varied from 67.6% (Hokkaido-Tohoku) to 84.8% (Kansai) (P＜0.001), while the amputation rates varied from 22.2% (Kansai) to 33.4% (Chugoku-Shikoku) (P＜0.001). The in-hospital mortality rates varied from 5.7% (Chugoku-Shikoku) to 10.9% (Okinawa) (P = 0.001). Conclusions: This study revealed significant regional disparities in CLI incidence, management, and outcomes across Japan. These findings highlight the need for standardized, evidence-based care strategies that address regional disparities to improve outcomes for patients with CLI.