Table 2. Comparison of adherence measures.
| Adherence measure | Cutoff value | Adherent N (%) |
Sensitivity (%) |
Specificity(%) | PPV (%) |
NPV (%) |
OR (95% CI) |
|---|---|---|---|---|---|---|---|
| Pharmacy refill adherence when leftover medication in included (PRL) N = 196 |
≤ 100 | 129 (65.8) | 67.8 | 52.6 | 93.0 | 14.9 | 2.34 (0.90–6.07) |
| ≤ 95 | 147 (75.0) | 77.4 | 47.4 | 93.2 | 18.4 | 3.08 (1.17–8.11) |
|
| ≤ 90 | 154 (78.6) | 80.8 | 42.1 | 92.9 | 19.0 | 3.06 (1.14–8.19) |
|
| ≤ 85 | 160 (81.6) | 84.2 | 42.1 | 93.1 | 22.2 | 3.87 (1.43–10.48) |
|
| ≤ 80 | 168 (85.7) | 88.7 | 42.1 | 93.5 | 28.6 | 5.71 (2.05–15.88) |
|
| ≤ 75 | 173 (88.3) | 91.0 | 36.8 | 93.1 | 30.4 | 5.87 (2.03–17.01) |
|
| ≤ 70 | 176 (89.3) | 92.1 | 31.6 | 92.6 | 30.0 | 5.37 (1.77–16.32) |
|
| Pharmacy refill adherence when leftover medication is excluded (PR) N = 233 |
≤ 100 | 104 (44.6) | 45.3 | 61.9 | 92.3 | 10.0 | 1.35 (0.54–3.38) |
| ≤ 95 | 132 (56.7) | 58.0 | 57.1 | 93.2 | 11.9 | 1.84 (0.74–4.56) |
|
| ≤ 90 | 157 (67.4) | 68.9 | 47.6 | 92.9 | 13.1 | 2.01 (0.81–4.97) |
|
| ≤ 85 | 168 (72.1) | 75.6 | 42.6 | 92.6 | 13.9 | 2.09 (0.84–5.23) |
|
| ≤ 80 | 183 (78.5) | 80.2 | 38.1 | 92.9 | 16.0 | 2.49 (0.97–6.39) |
|
| ≤ 75 | 193 (82.8) | 84.4 | 33.3 | 92.7 | 17.5 | 2.71 (1.02–7.23) |
|
| ≤ 70 | 198 (85.0) | 92.4 | 28.6 | 93.7 | 17.1 | 2.52 (0.91–7.03) |
|
|
Self-reported adherence N = 296 |
139 (47.0) | 49.2 | 71.9 | 93.5 | 14.6 | 2.48 (1.11–5.56) |
|
| Self-reported adherence among patients with PRL N = 195a |
92 (46.9) | 49.2 | 72.2 | 94.6 | 12.6 | 2.51 (0.86–7.35) |
|
| Self-reported adherence among patients with PR N = 232a |
109 (46.8) | 48.6 | 70.0 | 94.5 | 11.4 | 2.21 (0.82–5.96) |
Sensitivity, percentage of patients with undetectable viral load who are identified as adherent, Specificity, percentage of patients with detectable viral load who are identified as non-adherent; PPV, positive predictive value, percentage of adherent patients that has an undetectable viral load; NPV, negative predictive value, percentage of non-adherent patients that has a detectable viral load; PRL, pharmacy refill adherence when left over medication is included; PR, pharmacy refill adherence when left over medication is not included.
a Self-reported adherence data from 1 participant was missing.