PMH23 PREGABALIN FOR THE TREATMENT OF GENERALIZED ANXIETY DISORDERS (GAD) – A COST-EFFECTIVENESS CASE STUDY OF MEXICO

Abstract

OBJECTIVES: Of the various subtypes of anxiety disorders, generalized anxiety disorder (GAD) is the most frequent, lifetime prevalence 6.2%, and is connected with relevant economic and societal consequences. The aim of this study was to assess the cost-effectiveness of pregabalin in the treatment of GAD from an institutional perspective. METHOD(S): We developed a three-state Markov model to simulate health and economic outcomes during a time horizon of one-year (12-week cycles). The model includes several stages related to disability (complete response, partial response and relapse). Effectiveness was assumed as the percentage of patients with complete response at the end of the follow-up period using the Hamilton Anxiety Rating Scale (HAM-A) (50% reduction related to baseline score) and a Clinical Global Impression of Improvement (CGI-I) score of 1 or 2. Transition probabilities were obtained from a meta-analysis involving international published trials. Comparators used in the assessment were paroxetine (10-40 mg/day); venlafaxine (75-225 mg/day) and pregabalin (300-450 mg/day). Resource use and costs were obtained from 4,000 randomized hospital records from the Social Security Mexican Institute (IMSS). Costs included outpatient and inpatient services, drug, procedures, etc. The model was calibrated. Probabilistic sensitivity analyses were performed employing bootstrapping techniques and acceptability curves were constructed. RESULT(S): The highest percentage of patients with complete response to the HAM-A scale during the follow-up period was obtained by pregabalin (39.8%; CI95% 38.5%-41.1%), followed by venlafaxine (22.6%; CI95% 21.9%-23.4%) and paroxetine (16.5%; CI95% 16.0%-17.0%). Regarding the CGI-I the highest percentage for complete response was for pregabalin (35.3%; CI95% 34.2%-36.5%); followed by venlafaxine (28.8%; CI95% 27.8%-29.7%) and paroxetine (16.6%; CI95% 16.1%- 17.2%). The annual expected mean costs per patient were US$1,893.1 (US$1,830.7-US$1955.4), US$2001.2(US$1935.3-US$2067.2) and US$955.1(US$923.6- US$986.5). The ICER for pregabalin vs. paroxetine (baseline) was US$4019.7 (US$3887.3-US$4153.7) for HAM-A and US$5017.9(US$4852.6-US$5183.2) for CGI-I. Second-order Monte Carlo sensitivity analyses showed that pregabalin was a cost-effective therapy (p <0.05). CONCLUSION(S): Pregabalin showed to be a costeffective therapy due to its higher effi cacy response in the management of GAD.