Abstract
Purpose: :
To determine the degree to which primary open–angle glaucoma or ocular hypertension subjects’ self–reports of eyedrop administration ability can predict clinician–observed dosing success.
Methods: :
This was a randomized, open–label, two–way crossover, multicenter study of 90 adult subjects. At baseline, subjects completed the Treatment Satisfaction Survey for Intraocular Pressure questionnaire (TSS–IOP), a multidimensional measure of medication satisfaction. Subsequently, each subject was observed applying eyedrops to each eye from a conventional dropper bottle at 30–minute intervals for a total of four sessions. The clinician observers documented drop delivery success in reaching the eye as follows: the first drop at the fourth time point; the first drop at any time point; and the average number of drops used per session. The association of delivery success and the Ease of Administration (EoA) composite and individual item scores (perceptions of accuracy, head angle difficulty, and dose confidence) are reported.
Results: :
The mean age was 67.3 years (range: 41 to 87) with 60% female. Scores on the perceived accuracy item of the EoA were significantly correlated with all three observed observational measures in that lower scores were associated with less observed accuracy (p=0.0266, p=0.0010, and p=0.0013, respectively). Patients reporting lower confidence in their ability to dose accurately were observed to use more drops per session than those who were confident (p=0.0148). The association of patient self–reported ability to angle their head and dosing observation was not significant for first dose accuracy at the first or any time point but was significant for average number of drops used (p = 0.3238, p=0.0806, and p=0.0375, respectively). The composite domain score was significantly associated with success of the first attempt at any time point (p=0.0045) and the average number of drops used (p=0.0080) but not for the first dose at the fourth time point (p=0.1124). When the sample was bifurcated based on the median number of drops used, item and domain scores were significantly different (p<0.05) between the groups supporting the predictive validity of the measure.
Conclusions: :
EoA composite measure and individual item scores are generally associated with observed accuracy. Patient self–report is an accurate predictor of observed success in self–administration. These results support the utility of self–report as an indicator of administration difficulty and may help clinicians identify patients at risk for dosing noncompliance.
Keywords: clinical (human) or epidemiologic studies: outcomes/complications • clinical research methodology