Caffeine is a commonly ingested psychoactive substance which affects alertness and cognition. A clinical study was conducted to determine the effect of orally ingested caffeine on visual analogue scale (VAS) responses...Caffeine is a commonly ingested psychoactive substance which affects alertness and cognition. A clinical study was conducted to determine the effect of orally ingested caffeine on visual analogue scale (VAS) responses in healthy, moderate caffeine-consuming volunteers through the use of population pharmacokinetic-pharmacodynamic (PK-PD) modeling. Twelve subjects were recruited for a three-period cross-over study which utilized caffeine containing beverages. Each visit included 8-hour blood plasma and VAS response collection for PK and PD assessment respectively. The VAS used in the study, also called the caffeine analog scale, has been previously validated for caffeine. Population PK-PD modeling was conducted with NONMEM 7.2. Simultaneous and sequential modeling of PK-PD was attempted. Final model selection was based on parameter estimate precision, diagnostic plots, and visual predictive check (VPC) plots. Results showed that a one-compartment open model with first-order absorption and elimination best described the pharmacokinetics of caffeine. Sequential PK-PD modeling was successful and an effect compartment model with linear slope and baseline parameter best described caffeine pharmacodynamics. Diagnostic plots showed no major bias and VPC plots showed agreement between observations and predictions. The model was able to link VAS responses to caffeine concentration in healthy volunteers and may be useful in clinical trial simulations and design.展开更多
Introduction: The Liebowitz Social Anxiety Scale (LSAS), used to assess the severity of social anxiety disorder (SAD), requires considerable effort and time to complete. The aims of this study were: 1) to investigate ...Introduction: The Liebowitz Social Anxiety Scale (LSAS), used to assess the severity of social anxiety disorder (SAD), requires considerable effort and time to complete. The aims of this study were: 1) to investigate whether a visual analogue scale (VAS) could be linear with the LSAS and substitute for the LSAS, 2) to relate such a VAS instrument to patient demographics. Methods: Fifty SAD patients were assessed using the LSAS and VAS instruments completed by both patients and doctors at the same session. We then drew distributions and calculated the Spearman’s ρ and κ coefficient values (divided at the median for each scale) between patient and doctor assessments. Next, each pair among the scores for the LSAS, the patient VAS and the doctor VAS was compared using Wilcoxon rank sum tests according to patient life profile data. Results: Scatter plots of pairs of scores were obtained. Spearman’s ρ was 0.661 between the LSAS and the patient VAS, 0.461 between the LSAS and the doctor VAS, and 0.494 between VAS scores of patients and doctors. The κ coefficients were 0.501 between the LSAS and patient VAS, 0.251 between the LSAS and doctor VAS, and 0.425 between patient VAS and doctor VAS (for all six, p < 0.001). The Wilcoxon rank sum tests indicated a significant difference between the groups with/ without “employment” (LSAS, patient/doctor VAS), with/without “graduation from junior college/university” (doctor VAS) (p < 0.05) and with/without marital history (the age of first consultation) (p < 0.01). Conclusions: A patient VAS may substitute for the LSAS and offer the versatility necessary to capture patient states and life profiles.展开更多
文摘Caffeine is a commonly ingested psychoactive substance which affects alertness and cognition. A clinical study was conducted to determine the effect of orally ingested caffeine on visual analogue scale (VAS) responses in healthy, moderate caffeine-consuming volunteers through the use of population pharmacokinetic-pharmacodynamic (PK-PD) modeling. Twelve subjects were recruited for a three-period cross-over study which utilized caffeine containing beverages. Each visit included 8-hour blood plasma and VAS response collection for PK and PD assessment respectively. The VAS used in the study, also called the caffeine analog scale, has been previously validated for caffeine. Population PK-PD modeling was conducted with NONMEM 7.2. Simultaneous and sequential modeling of PK-PD was attempted. Final model selection was based on parameter estimate precision, diagnostic plots, and visual predictive check (VPC) plots. Results showed that a one-compartment open model with first-order absorption and elimination best described the pharmacokinetics of caffeine. Sequential PK-PD modeling was successful and an effect compartment model with linear slope and baseline parameter best described caffeine pharmacodynamics. Diagnostic plots showed no major bias and VPC plots showed agreement between observations and predictions. The model was able to link VAS responses to caffeine concentration in healthy volunteers and may be useful in clinical trial simulations and design.
文摘Introduction: The Liebowitz Social Anxiety Scale (LSAS), used to assess the severity of social anxiety disorder (SAD), requires considerable effort and time to complete. The aims of this study were: 1) to investigate whether a visual analogue scale (VAS) could be linear with the LSAS and substitute for the LSAS, 2) to relate such a VAS instrument to patient demographics. Methods: Fifty SAD patients were assessed using the LSAS and VAS instruments completed by both patients and doctors at the same session. We then drew distributions and calculated the Spearman’s ρ and κ coefficient values (divided at the median for each scale) between patient and doctor assessments. Next, each pair among the scores for the LSAS, the patient VAS and the doctor VAS was compared using Wilcoxon rank sum tests according to patient life profile data. Results: Scatter plots of pairs of scores were obtained. Spearman’s ρ was 0.661 between the LSAS and the patient VAS, 0.461 between the LSAS and the doctor VAS, and 0.494 between VAS scores of patients and doctors. The κ coefficients were 0.501 between the LSAS and patient VAS, 0.251 between the LSAS and doctor VAS, and 0.425 between patient VAS and doctor VAS (for all six, p < 0.001). The Wilcoxon rank sum tests indicated a significant difference between the groups with/ without “employment” (LSAS, patient/doctor VAS), with/without “graduation from junior college/university” (doctor VAS) (p < 0.05) and with/without marital history (the age of first consultation) (p < 0.01). Conclusions: A patient VAS may substitute for the LSAS and offer the versatility necessary to capture patient states and life profiles.
