Table 1 Characteristics of the included studies

1- Adel Alhazzani et al. [13]

Pharmacogenetics of CYP2C19 genetic polymorphism on clopidogrel response in patients with ischemic stroke from Saudi Arabia

Neurology Clinics at Aseer Central Hospital, Abha, Kingdom of Saudi Arabia, between October 2015 and January 2016

Retrospective study

50 patients on 75 mg maintenance dose of clopidogrel therapy suffering from stroke

To assess the influence of CYP2C19 genetic polymorphisms on the response to clopidogrel in ischemic stroke in Saudi Arabian population

The variant allele (homozygous and homozygous Mutant) showed significant influence on platelet inhibition and the antiplatelet effect of clopidogrel in ischemic stroke

2-Khalil et al. [22]

Genetic and Nongenetic Factors Affecting Clopidogrel Response in the Egyptian Population

Hospital network in Chicago, Illinois between 5 March and 6 April 2020

Retrospective study

190 patients with acute coronary syndrome (ACS) treated with clopidogrel (75 mg/day) for at least a month

To investigate genetic and non-genetic factors associated with clopidogrel response in Egyptians

CYP2C19 loss-of-function (LOF) alleles carriers had increased risk of recurrent CVES vs. noncarriers (odds ratio 2.52; 95% confidence interval 1.23–5.15, P = 0.011)

3-Abid et al. [19]

Impact of cytochrome P450 2C19*2 polymorphism on the clinical cardiovascular events after stent implantation in patients receiving clopidogrel of a southern Tunisian region

Department of Cardiology of Sfax (Tunisia) May 2009 and September 2010

Prospective study

100 consecutive patients admitted to the cardiology department for percutaneous coronary stenting. 2 groups: those with at least one CYP2C19*2 allele (*2 carriers) and non-carriers

to investigate the genetic variant of the gene CYP 2C19 in our population To assess the involvement of this genetic profile in the occurrence of major cardiovascular events

The prevalence of CYP2C19*2 allele was 11.5%. No statistically significant differences were noted between the two groups regarding the occurrence of intra hospital recurrent CVES

4- Mohammad et al. [23]

CYP2C19 genotype is an independent predictor of Adverse Cardiovascular Outcome in Iraqi Patients on Clopidogrel Post Percutaneous Coronary Intervention

Duhok Heart center, Kurdistan-Iraq, in the period between Jan 2014 to Mar 2017

Prospective study

201 unselected patients undergoing percutaneous coronary intervention (PCI) aged 35–82 (M:F = 1.9:1)

186 patients had regular follow up

To determine the impact of CYP2C19 genotyping on the occurrence of major adverse cardiovascular events (recurrent CVES)

The risk of recurrent CVES is 8.6% after a median follow-up of 12 months,

5- Ayesh et al. [21]

The clinical effects of CYP2C19*2 allele frequency on Palestinian patients receiving clopidogrel after percutaneous coronary intervention

The cardiology department of the European Gaza Hospital (EGH). March and the end of May 2014

Prospective study

110 consecutive unrelated post-PCI patients

To determine the prevalence of CYP2C19*2 and *3 alleles in Palestinian patients with percutaneous coronary intervention

The frequency of CYP2C19 *1, *2 and *3 alleles was 82.3%, 15.5% and 2.3%, respectively

6- Al-Azzam et al. [20]

Factors that contribute to clopidogrel resistance in cardiovascular disease patients: environmental and genetic approach

King Abdullah University Hospital (KAUH) and Jordan University Hospital (JUH) in the period between November 2010 and June 2011

Cross-section study

270 cardiovascular disease patients

To investigate factors that contribute to clopidogrel resistance

Gender, concomitant use of calcium channel blockers, HDL and CYP2C19*2 polymorphism are significant factors

7- Ahmad et al. [26]

Analysis of Gene Polymorphism CYP2C19 in the Lebanese Population Who Reside in Colombia

three Lebanese volunteers residents of Colombia

Cross-section study

109, 38 women and 71 men between 18 and 75 years

To determine the polymorphism of the CYP2C19 gene in the Lebanese

Similar behavior with the alleles frequencies of the previous studies made in Colombia, Africa, Europe and other American population

8-Rjoub et al. [25]

Allelic frequency of PON1 Q192R, CYP2C19*2 and CYP2C19*17 among Jordanian patients taking clopidogrel

among Jordanian patients in University of Jordan

Cross-section study

148 unrelated Jordanian patients who were taking clopidogrel (55 females and 95 males)

To investigate the influence of allelic frequencies of PON1 Q192R, CYP2C19*2 and CYP2C19*17 genetic polymorphisms on the response to clopidogrel

The CYP2C19*2, CYP2C19*17, and PON1 Q192R allele frequencies were 9.8, 28.72 and 28.7%, respectively

9- Khalaf et al. [27]

Impact of Cytochrome P450 2C19*2 and *3 on Clopidogrel Loading Dose in Saudi Patients with Acute Coronary Syndrome

Prince Sultan Cardiac Center, Buraidah, Saudi Arabia

Prospective study

90 patients underwent coronary angioplasty with drug eluting stents

To evaluate the impact of CYP2C19 allele *2 and allele *3 on PRU and the potential clinical consequences of such interaction

Genotypes *1/*1, *2/*2, and *1/*2 were expressed by 60, 28, and two patients (67, 32, and 3%), respectively

10- Al-Jenoobi et al. [24]

CYP2C19 Genetic Polymorphism in Saudi Arabians

King Saud University, Riyadh, Saudi Arabia Different geographic regions

Cross-section study

192 healthy unrelated Saudi Arabians

To evaluate CYP2C19 genetic polymorphism in a Saudi Arabian population by determining frequencies of CYP2C19*2, *3, *4, *6, *7 and *17 alleles

The allelic frequency of heterozygous CYP2C19*2 was 8.2% with only one individual carry the homozygous genotype of this defective allele