Indirect effect of the COVID-19 pandemic on cardiovascular diseases incidence, mortality, and healthcare use among patients with hypertension but without SARS-CoV-2 infection in Hong Kong: an interrupted time series analysis

This study investigated the effects of the COVID-19 pandemic on cardiovascular disease (CVD) incidence among hypertensive patients without SARS-CoV-2 infection by changes in CVD incidence, all-cause mortality, blood pressure (BP) control, and healthcare utilization rates among this population from Hong Kong. Individuals diagnosed with hypertension from January 2010 to January 2020 were followed up until death, SARS-CoV infection, or April 2022. Interrupted time series analyses on 1,318,907 patients with hypertension, comparing outcomes across four periods: pre-pandemic (January 2012-January 2020), early pandemic (February 2020-February 2021), interwave (March-December 2021), and Omicron outbreak (January-April 2022). A significant increase in out-of-hospital mortality was found when the early pandemic started. Overall all-cause mortality increased progressively during the interwave period. CVD incidence decreased immediately in the early pandemic period, followed by a progressive increase, and surpassed the pre-pandemic level at the beginning of the interwave period. The proportion of patients with office-measured BP ≤ 140/90 mmHg remained below pre-pandemic levels across the pandemic periods. Healthcare utilization declined immediately in February 2020, while most utilization rebounded to the pre-pandemic level after March 2021 and declined again during the Omicron outbreak. Healthcare disruptions during the early pandemic likely delayed CVD diagnosis and treatment, driving an immediate rise in out-of-hospital mortality. When healthcare services gradually recovered in the interwave period, CVD incidence rebounded and both in and out-of-hospital all-cause mortality increased with a lag, possibly related to delayed treatment.