Another cumulative study of 18 studies by Yan-ping Bao et al showed that patients using methadone at least 60mg / day tended to adhere treatment better than taking under 60mg / day (OR: 1, 74; 95% CI: 1, 43 - 2, 11), and taking the dosage flexibly would help patients to adhere treatment better than doing fixedly (OR: 1, 72; 95% CI: 1, 41 - 2, 11).