Sensitivity of the ICD-10 diagnoses was 79.9 % ( 95 % CI : 78.1-81 .3 % ) , specificity 83.9 % ( 95 % CI : 82.6-85 .1 % ) , positive likelihood ratio 4.95 ( 95 % CI : 4.58-5 .36 ) and negative likelihood ratio 0.24 ( 95 % CI : 0.22-0 .26 ) .