Reasons commonly cited for missed doses included forgetting and being away from home.
However, the concentration-based variables were derived without PK samples below the limit of quantification (BLQ) and an additional covariate, presence/absence of one or more such samples (assumed to result from ≥3 consecutive/clustered missed doses) was included to account for poor adherence.
Enlarging the sample size is an effective way to reduce biases and after combining the several cross-sectional surveys, education and self-reported missing doses in the past month were included into the final multivariate logistic regression models.
Items also included were reasons for missing doses in the past month.
The third part included questions about medication adherence self-efficacy, reasons for missing doses, and adherence aids.
The causes of missing doses or nonadherence in this study are similar to those in other studies; these reasons include simply forgetting (63%) and side effects (16%).
Of those starting postexposure prophylaxis, 37 (54%) persons reported missing doses.
Questions included whether infants missed doses since the previous visit, the number of days missed and the reason for missed doses.
The adherence questionnaire was developed and validated in this setting through previous qualitative and quantitative work and included questions about missed doses, barriers to adherence, and medication taking behaviors (Vreeman, Nyandiko, Ayaya, Walumbe, & Inui, 2014; Vreeman, Nyandiko, Liu, et al., 2014; Vreeman, Wiehe, Pearce, & Nyandiko, 2008; Vreeman et al., 2009).
We probed in detail about episodes of missed or delayed antiretroviral doses, including the exact circumstances surrounding the missed or delayed doses, the patient's feelings about the missed or delayed doses, and the specific impact of transportation costs, food shortages, and any other structural factors on ARV adherence when volunteered by the participant.
