This secondary analysis of a multicenter, randomized, flexible-dosage, placebo-controlled, double-blind, parallel-group trial evaluated the efficacy of pregabalin, based on baseline anxiety symptom severity, as treatment of GAD in patients ≥65 years.

Patients underwent an 8-week double-blind, flexible-dosage (150-600 mg/d) treatment phase, including a 1-week dose-escalation period (50 mg/d to 150 mg/d). The study's primary efficacy measure was mean change from baseline to endpoint-LOCF in HAM-A total score. To determine whether baseline symptom severity influenced pregabalin's efficacy, we evaluated patient subgroups with baseline HAM-A total scores of ≥20 (pregabalin n=171, placebo n=95), ≥22 (pregabalin n=146, placebo n=85), ≥24 (pregabalin n=120, placebo n=72), ≥26 (pregabalin n=93, placebo n=48), and ≥28 (pregabalin n=65, placebo n=28).

Patients' mean age was 72 years, and mean duration of their GAD was 17 years. 77% were women. 177 patients received pregabalin; 96 received placebo. Pregabalin was significantly superior to placebo on the primary outcome measure: mean change from baseline in HAM-A total score was –12.84 for pregabalin and –10.7 for placebo (P=.044). Treatment differences between pregabalin and placebo for each symptom-severity stratum were: ≥20, –2.18 (P=.044); ≥22, –2.37 (P=.047); ≥24, –2.80 (P=.035); ≥26, –2.70 (P=.096); ≥28, –3.07 (P=.156). Comparison of effect sizes (pregabalin vs placebo at endpoint) showed sustained benefit as the severity of baseline anxiety symptoms increased: ≥20, 0.261; ≥22, 0.276; ≥24, 0.324; ≥26, 0.301; ≥28, 0.332.

Pregabalin efficaciously reduced the symptoms of GAD in patients aged 65 years and older, regardless of the severity of their anxiety symptoms at baseline.