Table 2.
Validity indices and proportion of false-positive adherers for self-reported measurements of adherence using pill count adherence as the reference test.
| Type of self-reported measurement of adherence | |||
|---|---|---|---|
| Non-adherence on MARS |
Non-adherence on Previous Month Adherence |
Non-adherence on Previous Week Adherence |
|
| Sensitivity | 19.60 | 16.80 | 15.80 |
| Specificity | 89.90 | 92.80 | 94.20 |
| Positive Predictive Value | 36.40 | 40.50 | 44.40 |
| Negative Predictive Value | 79.20 | 79.20 | 79.30 |
| Percent Agreement | 73.90 | 75.50 | 76.50 |
| Cohen’s kappa (%) | 11.4 | 12.1 | 13.0 |
| Area under the curve (AUC) | 0.55 | 0.55 | 0.55 |
| False Positive Adherers (%)a | 19.80 | 20.00 | 20.00 |
Abbreviations: AUC, Area under the curve, MARS, Medication adherence report scale.
a
Proportion of false positive adherers was calculated as the ratio of the number of participants who were non-adherers based on pill count adherence ratio (PCAR<80%) but adherers based on self-reported measurements to the total number of participants.