Table 1. . Summary of included studies .
| n | Test type | Average age | Age range or SD | Women (%) | Description of sample | Country | Equity comment | GRADE | Ref. | |
|---|---|---|---|---|---|---|---|---|---|---|
| T = 362; C = 194; AA = 168 | CYP2C9 (*2 and *3) and VKORC (11173 C/T) genotype | 58.7 | 45–72 | 30.9 | A prospective cohort of patients (of various indications) with a target international normalized ratio of between 2.0 and 3.0 were genotyped | USA | Uncertain usefulness of variants in African–Americans to provide predictive information in anticoagulation response | Ethnicity - | 3 | [13] |
| T = 575; EA = 302; AA = 273 | CYP2C9 (*2, *3, *5, *6 and *11) and VKORC1 (1173C/T, 3730G/A, 2255C/T, 1542G/C) genotype | 61.1 | SD +14.7–16.0 | 48.7 | A prospective cohort of patients (of various indications) with a target international normalized ratio of between 2.0 and 3.0 were genotyped | USA | Inconsistent ability to provide predictive information in anticoagulation response | Ethnicity - | 3 | [14] |
| T = 366; M = 49; PI = 21; CH = 9 | CYP2C9 (*2 and *3) and VKORC1 (1639G/A) genotype | 68.6 | SD +9–12 | – | A prospective cross-sectional simulation study of patients with severe coronary disease | New Zealand | Study guides warfarin maintenance dose and therefore may reduce ethnic disparities in treatment outcomes | Ethnicity + | 2 | [15] |
| T = 3672; W = 2543; B = 639; J = 227; CH = 263 | CYP2C9 (*2 and *3) and VKORC1 (1639AA) genotype | – | – | – | Patients included in IWPC dataset from 22 study sites with a target international normalized ratio of between 2.0 and 3.0 | Singapore | Warfarin PGx testing reduces inaccurate dosing in white patients but black, Japanese and Chinese do not benefit | Ethnicity - | 3 | [16] |
| T = 13608; E=-; M=-; ETA=-; PI=- | CYP2C19 (*2) genotype | – | 45–80 | – | Cost–effectiveness analysis using international multicenter RCT data of genetic testing for CYP2C19 variants to guide thienopyridine treatment patients with ACS | New Zealand | Treatment strategy has potential to reduce ethnic health disparities | Ethnicity + | 2 | [17] |
AA: African–American; ACS: Acute coronary syndrome; B: Black; C: Caucasian; CH: Chinese; E: European; EA: European–American; ETA: East Asian; IWPC: International warfarin pharmacogenetics consortium; J: Japanese; M: Mãori; PGx: Pharmacogenetic test; PI: Pacific Islander; SD: Standard deviation; T: Total; W: White.