Follow-up Ratio Research Articles

Glaucoma Medication Adherence in Veterans and Influence of Coexisting Chronic Disease

The aim of this study was to characterize veterans' adherence to glaucoma medications and follow-up eye care, and to examine the influence of coexisting chronic conditions such as posttraumatic stress disorder (PTSD)/anxiety. A retrospective review of computerized medical records was performed for 161 veterans taking topical glaucoma medications. Medication possession ratio (MPR) was calculated using pharmacy data. Mean follow-up ratio (FUR) was calculated using the number of days between visits. Among the health conditions examined, the most prevalent was hearing loss (0.34), followed by arthritis (0.29), PTSD, or other anxiety disorder (0.27), and dementia or other memory disorder (0.09). The average rates of MPR and FUR were 0.69±0.20 and 0.84±0.19, respectively.Group comparisons found that patients with hearing loss had higher MPR compared with patients without hearing loss, and patients who were white had higher FUR than African American patients. When demographic and health characteristics were examined simultaneously in multiple linear regressions, hearing loss emerged as a significant predictor of MPR, and being older was significantly related to FUR. Younger age was also associated with MPR and being white (vs. African American) or having a PTSD/other anxiety disorder was related to FUR, although these findings did not reach statistical significance. FUR was better than MPR in a veteran population being treated for glaucoma.Hearing loss was significantly related to higher MPR, whereas being older was significantly associated with higher FUR. These characteristics should be taken into consideration in future programs to improve adherence to glaucoma care.

Changes in imatinib plasma trough level during long-term treatment of patients with advanced gastrointestinal stromal tumors.

306 Background: Pharmacokinetic study in patients with gastrointestinal stromal tumors (GISTs) suggested that plasma concentrations of imatinib decrease following long-term exposure. We therefore measured changes in imatinib plasma trough levels (Cmin) after long-term exposure. Methods: Between November 2009 and May 2010, follow-up (FU) imatinib Cmin was measured in 65 patients who received the same dose of imatinib for at least 9 months after a previous baseline (BL) measurement. Total 244 blood samples were obtained (127 at BL and 117 at FU) and plasma level was measured by liquid chromatography-tandem mass spectrometry. Results: Median patient age was 54 years (range, 28–76 years) and 42 (64.6%) patients were male. Sixty-one (93.8%) patients were treated with 400 mg/day imatinib and 4 (6.2%) with 300 mg/day. The median interval from initiation of imatinib to BL test was 6.4 months (range, 0.5–66.6 months), and the median interval between BL and FU test was 13.1 months (range, 9.6–18.4 months). The mean ± standard deviation imatinib Cmin was significantly higher at FU than at BL (1442 ± 693 ng/mL vs 1221 ± 624 ng/mL, p<0.001). The mean inter- and intra-subject variabilities were 49.2% and 25.5%, respectively, at BL, and 44.2% and 20.4%, respectively, at FU. Multivariate analysis showed a significant correlation between the ratio of FU to BL imatinib Cmin and that of albumin (r=-0.397, p=0.001). In per-sample analysis, imatinib Cmin was significantly correlated with age, hemoglobin, albumin, creatinine clearance, previous major gastrectomy and time between initiation of imatinib and plasma level tests. Conclusions: Steady-state imatinib Cmin did not decrease but remained stable in most GIST patients during long-term treatment. Changes in imatinib Cmin were associated with changes in albumin concentration. Monitoring of imatinib Cmin only for concerns about time-dependent decreases in imatinib exposure is not necessary. [Table: see text]

Changes in imatinib plasma trough level during long-term treatment of patients with advanced gastrointestinal stromal tumors: correlation between changes in covariates and imatinib exposure

A pharmacokinetic study in patients with gastrointestinal stromal tumors (GIST) suggested that imatinib plasma concentration may decrease following long-term exposure. We assessed changes in imatinib plasma trough levels (C(min)) during long-term treatment. Follow-up (FU) imatinib C(min) was measured in 65 patients who received the same dose of imatinib for at least 9 months after previous (initial) tests. After exclusion of 7 patients who had been treated with imatinib for over 2 years at the time of initial testing, 58 patients were included in this analysis. The median intervals from initiation of imatinib to initial testing and from initial to FU testing were 5.5 months (range, 0.5-24.0 months) and 13.0 months (range, 9.6-17.9 months), respectively. Mean inter- and intra-subject variability values were 47.7% and 20.9%, respectively, at initial measurements, and 45.2% and 19.4%, respectively, at FU. Mean FU imatinib C(min) (1,370 ± 661 ng/mL) was significantly higher than mean initial C(min) (1,171 ± 573 ng/mL; p = 0.003). Compared with initial C(min), FU C(min) was decreased in 22 patients and increased in 36, with median changes of 13% and 32%, respectively. Multivariate analysis showed a significant correlation between the ratio of FU to initial imatinib C(min) and that of albumin (r = -0.39, p = 0.003). During long-term treatment, imatinib C(min) did not decrease significantly but remained stable or increased in most patients. Changes in imatinib C(min) were associated with changes in albumin concentration. Monitoring of imatinib C(min) only for concerns about time-dependent increases in imatinib clearance is not necessary.