This is a retrospective, observational, descriptive study which will include patients hospitalized for acute coronary syndrome (ACS) and treated with ticagrelor at discharge. Participants will come from the follow-up program of ACS patients taking ticagrelor 90 mg twice a day as part of the dual antiplatelet therapy at discharge. The primary objectives were to describe the ticagrelor treatment patterns-Ticagrelor persistence, discontinuation, switching, interruption and reasons in Chinese ACS patients; and also to describe 1-year clinical outcomes (Composite of any cause death, myocardial infarction, and stroke) of Chinese ACS patients in real-life practice based on ACS patient follow-up program database.

Background： There are at least 2.5 million acute coronary syndromes (ACS) patients in China per year. Limited data about long term ticagrelor treatment patterns and clinical outcomes in Chinese ACS patients due to the lack of large high quality follow up database. This study is based on real-life practice and ticagrelor is prescribed according to the Chinese guideline and it takes place in real life.

Objective of this study:

Primary Objectives:

1. To describe the ticagrelor treatment patterns-Ticagrelor persistence, discontinuation, switching, interruption and reasons for discontinuation/switching/interruption in Chinese ACS patients.
2. To describe 1-year clinical outcomes (Composite of any cause death, myocardial infarction, and stroke) of Chinese ACS patients in real-life practice based on ACS patient follow-up program database.

Secondary Objectives:

1. To describe the impact of ticagrelor treatment pattern on clinical outcomes. (No confirmed conclusions regarding the efficacy or impact of ticagrelor treatment patterns will be drawn because of descriptive analysis.)
2. To analyze influence factors (age, region, hypertension, diabetes, chronic kidney disease (CKD), smoking, education, insurance etc) related to clinical outcomes

Exploratory Objectives:

To explore the influence factors (age, region, education, insurance, event, etc.) with ticagrelor treatment pattern; Analysis of other possible factors (such as smoke, low density lipoprotein-chlesterol [LDL-C]) affecting the prognosis of patients with ACS; Analysis of possible interactions and their influences between different factors associated with the prognosis of patients with ACS

Study design:

This is a retrospective, observational, descriptive study which will include patients hospitalized for ACS and treated with ticagrelor at discharge.

Data source：

Study participants： Participants will come from the follow-up program of ACS patients taking ticagrelor 90 mg twice a day as part of the dual antiplatelet therapy at discharge. During the follow-up period for 12 months after discharge. Telephone follow-up will be done 1, 3, 6, 12 months after discharge according to a structured questionnaire assessing the primary and secondary objectives of this study. Telephone interviews will be performed by the local ACS patient follow-up program assistants (nurses who enters information in the websites).

Study Variables:

Primary variables:

1. Ticagrelor treatment patterns-Ticagrelor persistence, discontinuation, switch, interruption and reasons for switching/discontinuation/interruption

1. Ticagrelor persistence: Proportion of patients who is on ticagrelor treatment every month after discharge; Duration of time from initiation to discontinuation of therapy.
2. Proportion of patients with ticagrelor discontinuation, switching and interruption and related reasons; Discontinuation of medications was defined as a break for P2Y12 at least three months; Switching means from Ticagrelor/Clopidogrel to another P2Y12 inhibitor (Clopidogrel to ticagrelor means re-switching if they were recorded). Interruption was defined as Ticagrelor discontinuation for more than 1 day and less than 3 months) 2. Time to first occurrence of any of the following clinical events (Composite of any cause death, myocardial infarction, Stroke) within one year follow up.

Secondary variables:

1. Time to the first occurrence of each component of primary clinical events (any cause death, myocardial infarction, Stroke) in the first year after discharge.
2. Proportion of ticagrelor treatment patterns with different clinical outcomes
3. Correlation between risk factors (age, region, education, insurance, hypertension, diabetes, CKD, smoking, etc.) and clinical outcomes

Exploratory variables:

Association between ticagrelor persistence and risk factors (regions, education, reimbursement, etc.); Analysis of other possible factors (such as smoke, LDL-C, etc) affecting the prognosis of patients with ACS; Analysis of possible interactions and their influences between different factors associated with the prognosis of patients with ACS

Exposures of Interest:

Ticagrelor 90 mg used twice a day as part of dual antiplatelet therapy (DAPT) during first year after ACS

Outcomes of Interest:

1. Ticagrelor treatment patterns -Persistence, discontinuation rate, switching and interruption in Chinese ACS patients after hospital discharge;
2. Time of first occurrence of any of the end-point events (any cause death, myocardial infarction, Stroke) within one year follow up.

Limitations:

The study subjects are patients under ticagrelor treatment at discharge in China, which limits the generalization of the study results. The criteria for patients treated with ticagrelor might lead to patient selection bias. As some risk factors of cardiovascular disease (CVD) were not randomized, there might be unmeasured confounding.

Inclusion Criteria:

1. ACS patients hospitalized during the following period: from January 2019 to September 2019
2. Patients receiving ticagrelor as part of DAPT at hospital discharge.
3. Patient enrolled into the follow-up program of ACS patients

Exclusion Criteria:

Patients participated in other interventional clinical trials

ACS patients taking ticagrelor 90 mg twice a day as part of the dual antiplatelet therapy at discharge