Search

Background: Anxiety disorders are among the most common psychiatric illnesses, with generalized anxiety disorder (GAD) being one of the most common. Sleep disturbances are highly prevalent in GAD patients. While treatment with pregabalin has been found to be associated with significant improvement in GAD-related sleep disturbance across many controlled clinical trials, mediational analysis has suggested that a substantial portion of this effect could be the result of a direct effect of pregabalin. Thus, the objective of this study was to model the longitudinal latent effect of pregabalin or usual care (UC) therapies on changes in sleep in outpatients with GAD under routine clinical practice., Methods: Male and female GAD outpatients, aged 18 years or above, from a 6-month prospective noninterventional trial were analyzed. Direct and indirect effects of either pregabalin or UC changes in anxiety symptoms (assessed with Hamilton Anxiety Scale) and sleep disturbances (assessed with Medical Outcomes Study-Sleep Scale [MOS-S]) were estimated by a conditional latent curve model applying structural equation modeling., Results: A total of 1,546 pregabalin-naïve patients were analyzed, 984 receiving pregabalin and 562 UC. Both symptoms of anxiety and sleep disturbances were significantly improved in both groups, with higher mean (95% confidence interval) score reductions in subjects receiving pregabalin: -15.9 (-15.2; -16.6) vs -14.5 (-13.5; -15.5), P=0.027, in Hamilton Anxiety Scale; and -29.7 (-28.1; -31.3) vs -24.0 (-21.6; -26.4), P<0.001, in MOS-S. The conditional latent curve model showed that the pregabalin effect on sleep disturbances was significant (γ =-3.99, P<0.001), after discounting the effect on reduction in anxiety symptoms. A mediation model showed that 70% of the direct effect of pregabalin on sleep remained after discounting the mediated effect of anxiety improvement., Conclusion: A substantial proportion of the incremental improvements in anxiety-related sleep disturbances with pregabalin vs UC were explained by its direct effect, not mediated by improvements in anxiety symptoms.

Purpose: To model the cost-effectiveness (CEA) of the use of pregabalin versus usual care (UC) in outpatients with refractory generalised anxiety disorder (GAD) treated in daily practice in mental health settings in Spain., Methods: This CEA model used data extracted from a 6-month prospective non-interventional trial: the Amplification of Definition of ANxiety (ADAN) study, which was conducted to determine the cost-of-illness in GAD subjects. Refractory subjects were those who reported persistent symptoms of anxiety and showed suboptimal response in the Hamilton-anxiety scale (HAM-A ≥ 16) after a standard dose regimen of anxiolytics other than pregabalin, alone or in combination, over 6 months. The pregabalin arm was documented with data extracted from patients who received pregabalin in the study for the first time, added or replacing the existing therapy. In the UC arm, treatment might include one or more of the following: a serotonin selective reuptake inhibitor, a serotonin-norepinephrine reuptake inhibitor, other anti-depressants, a benzodiazepine or an anti-epileptic drug other than pregabalin. The time horizon of the modelling was 6 months in the base-case scenario, and the National Health System perspective was chosen to calculate costs. Effectiveness was expressed as quality-adjusted life years (QALYs) gained, which were derived using the EQ-5D questionnaire, at baseline and end-of-trial visits. Results of the CEA model was expressed as an incremental cost-effectiveness ratio (ICER) per QALY gained. Probabilistic sensitivity analysis using bootstrapping techniques was also carried out to obtain the cost-effectiveness plane and the corresponding acceptability curve., Results: Data from a total of 429 subjects per arm (mean HAM-A score 25.7) meeting eligible criteria for inclusion in CEA modelling were extracted from the original trial. Compared with UC, pregabalin (average dose 218 mg/day) was associated with significantly higher QALY gain; 0.1209 ± 0.1030 versus 0.0994 ± 0.0979 (P = 0.003), but increased healthcare costs as well; 1,272 ± 1,240 versus 1,070 ± 1,177 (P < 0.069) and drug costs 525 ± 252 versus 219 ± 211 (P < 0.001), resulting in an ICER of 15,804/QALY (95 % CI 6,661; 37,186) for healthcare costs and 15,165/QALY (7,947; 31,754) when drug costs were considered alone. A total of 94 % of re-samples fell below the threshold of 30,000 per QALY., Conclusions: This evaluation modelling suggests that pregabalin may be cost-effective in comparison with UC in outpatients with refractory GAD treated in mental healthcare settings in daily practice in Spain.