54, 55 , 60 , 62, 63, 64, 65, 66, 67, 68 , 70, 71, 72, 73, 74 , 76 In 3 studies including 1701 outpatients, the pooled prevalence was 4.0% (95% CI, 3.1%–5.1%).31 , 59 , 63 As par