Disease burden of subsequent events among patients with atherosclerotic cardiovascular disease in Taiwan
Authors: Chen W.J , Hsu C.Y , Lin H.J , Chen H.M , Chen W.J , Hsiao F.Y 
Published: November 2020

Abstract

Background/Introduction
Patients with a history of cardiovascular disease are considered at high risk for cardiovascular (CV) events. Existing studies have indicated that a high proportion of patients developed secondary or tertiary atherosclerotic cardiovascular disease (ASCVD) events within a relatively short period of time. However, the whole picture regarding when and how these subsequent CV events occur is not well understood, particularly in Asia.

Purpose
To estimate the incidences, characteristics and mortality of subsequent ASCVD events among those with new-onset ASCVD events (index events).

Methods
We utilized National Health Insurance Research Database in Taiwan to identify patients with new-onset ASCVD events (index events), and further categorized them into those with incident coronary heart disease (CHD), cerebrovascular disease (CBVD) and peripheral artery disease (PAD) during 2012–2014. Re-admission due to ASCVD after the index event, defined as subsequent ASCVD event, was our main outcome of interest. All subsequent ASCVD events within 3-year period after the index ASCVD events were identified. Particularly, we intended to sequentially identify first and second subsequent ASCVD events. Descriptive statistics regarding proportion of developing subsequent ASCVD events as well as the type of subsequent ASCVD events were estimated. We also used Kaplan-Meier method to estimate crude survival curve of all-cause mortality following each subsequent ASCVD event.

Results
We identified 97,321, 120,914 and 14,794 patients with new-onset CHD, CBVD and PAD, respectively. The proportion of developing subsequent events increased with sequence of events occurred (for the first three subsequent event, the proportions of developing subsequent event were: 22.5, 25.6 and 30.9% for CHD, 21.0, 26.2 and 32.4% for CBVD, and 40.2, 41.4 and 43.6% for PAD). The majority of patients had the same type of ASCVD for their subsequent events to the primary event (proportions of having the same ASCVD type of subsequent event to the primary event ranged: 66–81% for CHD, 80–84% for CBVD, and 76–78% for PAD). The 1-year readmission rates increased if patients encountered more subsequent events. Among patients with new-onset CHD, the 1-year readmission rates following new-onset events, first subsequent events and second subsequent events were 43.1%, 47.6% and 55.3%, respectively. More subsequent events also worsened the survival. The 1-year survival rates following new-onset CHD events, first subsequent events and second subsequent events were 85.9%, 84.3% and 79.8%, respectively. Similar trend was observed for CBVD and PAD patients as well.

Conclusions
Compared with new-onset ASCVD events, subsequent ASCVD events posed a heavier disease burden in terms of readmission and mortality. These results highlighted the importance of prevention of secondary or tertiary ASCVD events.

Funding Acknowledgement
Type of funding source: Private company. Main funding source(s): Amgen Taiwan Limited