ADJUNCTIVE THERAPY WITH PREGABALIN IN GENERALIZED ANXIETY DISORDER PATIENTS WITH PARTIAL RESPONSE TO SSRI TREATMENT: A COST-CONSEQUENCES ANALYSIS IN MEDICAL PRACTICE IN SPAIN

To compare the effect of adjunctive therapy with pregabalin versus usual care (UC) on health care costs and clinical and patients consequences in Generalized Anxiety Disorder (GAD) subjects with partial response (PR) to previous SSRI course in medical practice in Spain. Post-hoc analysis of patients with PR to SSRI monotherapy enrolled in a prospective 6-month naturalistic study. PR was defined as a Clinical-Global-Impression scale score >3 and insufficient response with persistence of anxiety symptoms >16 in the Hamilton-Anxiety scale. Two groups (based on psychiatrist judgment) were analyzed 1) adjunctive therapy (AT) with pregabalin (150-600 mg/day) to existing therapy; or 2) usual care (switching to a different SSRI or adding another anxiolytic different than pregabalin). Costs estimation used year-2009 prices for GAD related health care resources utilization. Consequences were a health profile based on the combination of psychiatrist-based-measurements [HAM-A, CGI and Montgomery-Asberg-Depression-Rating (MADRS) scales], and patient-reported-outcomes [sleep (MOS-sleep), disability (WHO-DAAS II) and quality-of-life/quality-adjusted-life-year gain (EQ-5D)]. Changes in both health care costs and scale scores were compared separately at end-of-trial visit by a general-linear-model with covariates. Four-hundred-eighty-six newly prescribed pregabalin and 239 UC GAD patients [mean (SD) HAM-A 26.7 (6.9) and CGI 4.1 (0.5)] were analyzed. Adding pregabalin was associated with significantly higher mean (95% CI) score reductions vs. UC in HAM-A [-14.9(-15.6;-14.2) vs. -11.2(-12.2;-10.2), p<0.001] and MADRS [-11.6(-12.2;-10.9) vs. -7.8(-8.7;-6.8), p<0.001]. Changes in all patient-reported-outcomes favored significantly patients receiving pregabalin, including QALY gain; 0.13(0.12;0.14) vs. 0.09(0.07;0.10), p<0.001. Health care costs were significantly reduced in both cohorts yielding similar 6-month costs; €1543 (1375;1711) UC and €1497 (1380;1614) pregabalin, p=0.661. The effect of sex on costs and consequences were negligible. In medical practice, GAD patients with PR to SSRI experienced greater consequences improvements with adjunctive therapy with pregabalin versus UC, without increasing health care cost. The effect of pregabalin was independent of patient gender.