In-Hospital Deaths From Ambulatory Care–Sensitive Conditions Before and During the COVID-19 Pandemic in Japan

IMPORTANCE: The COVID-19 pandemic may have played a role in the deterioration of access to medical care for ambulatory care–sensitive conditions (ACSCs). OBJECTIVE: To ascertain whether the number of in-hospital deaths and in-hospital mortality rate associated with ACSC changed after the declaration of the COVID-19 national state of emergency in Japan. DESIGN, SETTING, AND PARTICIPANTS: This cohort study used a difference-in-differences design to compare outcomes for ACSC in the period before (January 1, 2015, to December 31, 2019) vs the period after (January 1, 2020, to December 31, 2020) Japan declared a national state of emergency for the COVID-19 pandemic. Analyses used discharge summary data from 242 acute care hospitals across Japan. The sample comprised unscheduled hospitalizations of patients with ACSC during the study period (January 1, 2015, to December 31, 2020). Data analyses were performed between August 16 and December 7, 2022. EXPOSURE: The declaration of the COVID-19 national state of emergency announced by the Japanese government in April 2020 was considered to be an exogenous shock. MAIN OUTCOMES AND MEASURES: Primary outcomes were the ACSC-associated number of in-hospital deaths, number of hospitalizations, and in-hospital mortality rate. RESULTS: A total of 28 321 ACSC-related hospitalizations were observed involving 15 318 males (54.1%), with a median (IQR) age of 76 (58-85) years. The number of in-hospital deaths was 2117 (7.5%). The number of hospitalizations decreased overall (incidence rate ratio [IRR], 0.84; 95% CI, 0.75-0.94), for chronic conditions (IRR, 0.84; 95% CI, 0.77-0.92), and for vaccine-preventable conditions (IRR, 0.58; 95% CI, 0.44-0.76). However, in-hospital deaths (IRR, 1.66; 95% CI, 1.15-2.39) and in-hospital deaths within 24 hours of hospital arrival (IRR, 7.27 × 10(6); 95% CI, 1.83 × 10(6) to 2.89 × 10(7)) increased for acute conditions. The in-hospital mortality rate increased for acute conditions (IRR, 1.71; 95% CI, 1.16-2.54), and the 24-hour in-hospital mortality rates also increased overall (IRR, 1.87; 95% CI, 1.19-2.96), for acute conditions (IRR, 2.15 × 10(6); 95% CI, 5.25 × 10(5) to 8.79 × 10(6)), and for vaccine-preventable conditions (IRR, 4.64; 95% CI, 1.28-16.77). CONCLUSIONS AND RELEVANCE: This cohort study found that in Japan, the number of in-hospital deaths increased after the declaration of the COVID-19 national state of emergency in 2020, particularly for acute ACSC and deaths within 24 hours of hospital admission. This finding suggests that access to good-quality primary care and inpatient care for patients with acute ACSC may have been compromised during the pandemic.