Correlates of higher positive percentages among urine morphine (+) participants during the study period (n=268)
| Characteristics | <20% (n=68) | 20–60% (n=97) | >60% (n=103) | OR (95% CI)* | p* |
| No. (%)† | No. (%)† | No. (%)† | |||
| Age (years) | |||||
| ≤30 | 20 (32.3) | 28 (45.2) | 14 (22.6) | 0.31 (0.12 to 0.78) | 0.013 |
| 31– | 22 (27.5) | 26 (32.5) | 32 (40.0) | 0.44 (0.20 to 1.00) | 0.051 |
| 36– | 13 (15.7) | 33 (39.8) | 37 (44.6) | 0.91 (0.43 to 1.93) | 0.814 |
| ≥41 | 13 (30.2) | 10 (23.3) | 20 (46.5) | 1.00 | |
| Gender | |||||
| Male | 60 (24.7) | 90 (37.0) | 93 (38.3) | 0.97 (0.42 to 2.22) | 0.944 |
| Female | 8 (32.0) | 7 (28.0) | 10 (40.0) | 1.00 | |
| Marital status | |||||
| Never married | 36 (25.4) | 54 (38.0) | 52 (36.6) | 2.04 (0.92 to 4.55) | 0.080 |
| Married currently | 23 (25.0) | 29 (31.5) | 40 (43.5) | 1.93 (0.85 to 4.40) | 0.117 |
| Others | 9 (26.5) | 14 (41.2) | 11 (32.4) | 1.00 | |
| Education level | |||||
| Elementary or lower | 16 (25.4) | 24 (38.1) | 23 (36.5) | 1.50 (0.64 to 3.50) | 0.347 |
| Junior high school | 45 (25.9) | 58 (33.3) | 71 (40.8) | 1.48 (0.71 to 3.12) | 0.298 |
| Senior high school or higher | 7 (22.6) | 15 (48.4) | 9 (29.0) | 1.00 | |
| Employment status at baseline | |||||
| Unemployed | 45 (24.2) | 64 (34.4) | 77 (41.4) | 1.99 (1.13 to 3.49) | 0.017 |
| Employed | 23 (28.0) | 33 (40.2) | 26 (31.7) | 1.00 | |
| Mainly financial sources | |||||
| Family or friends | 49 (29.0) | 60 (35.5) | 60 (35.5) | 0.55 (0.32 to 0.93) | 0.025 |
| Others | 19 (19.2) | 37 (37.4) | 43 (43.4) | 1.00 | |
| Duration of drug use (years) | |||||
| ≤10 | 18 (29.0) | 21 (33.9) | 23 (37.1) | 1.04 (0.50 to 2.16) | 0.923 |
| 11–15 | 27 (22.9) | 46 (39.0) | 45 (38.1) | 1.38 (0.75 to 2.55) | 0.305 |
| ≥16 | 23 (26.1) | 30 (34.1) | 35 (39.8) | 1.00 | |
| Average times of drug use per day | |||||
| ≤2 | 21 (19.3) | 47 (43.1) | 41 (37.6) | 1.03 (0.62 to 1.71) | 0.912 |
| ≥3 | 47 (29.6) | 50 (31.4) | 62 (39.0) | 1.00 | |
| Shared needles at baseline | |||||
| Yes | 38 (24.8) | 59 (38.6) | 56 (36.6) | 1.03 (0.63 to 1.69) | 0.902 |
| No | 30 (26.1) | 38 (33.0) | 47 (40.9) | 1.00 | |
| Multiple sexual partners at baseline | |||||
| Yes | 12 (20.3) | 17 (28.8) | 30 (50.8) | 1.65 (0.89 to 3.05) | 0.113 |
| No | 56 (26.8) | 80 (38.3) | 73 (34.9) | 1.00 | |
| Average maintenance doses (mL/day) | |||||
| ≥60 | 36 (26.1) | 56 (40.6) | 46 (33.3) | 0.92 (0.57 to 1.49) | 0.742 |
| <60 | 32 (24.6) | 41 (31.5) | 57 (43.8) | 1.00 | |
| MMT attendance (%) | |||||
| <20 | 4 (13.3) | 9 (30.0) | 17 (56.7) | 3.60 (1.55 to 8.33) | 0.003 |
| 20– | 10 (16.1) | 19 (30.6) | 33 (53.2) | 2.80 (1.48 to 5.33) | 0.002 |
| 50– | 22 (30.1) | 32 (43.8) | 19 (26.0) | 0.94 (0.53 to 1.67) | 0.841 |
| ≥80% | 32 (31.1) | 37 (35.9) | 34 (33.0) | 1.00 |
*Obtained from multivariate ordinal logistic regression analysis adjusting for potential confounding variables listed in the table.
† Proportions were calculated in the row.