Lastly, for ICD-10-CM PTH, we observed the same pattern for specific ICD-9-CM:ICD-10-CM headache types (PTH aOR = 22.47, 95% CI: 18.51–27.29) and the significance of specialists after controlling comorbidity in ICD-9-CM and ICD-10-CM (Neurology [aOR = 5.70, 95% CI: 5.05–6.43] and [Physiatry aOR = 2.21, 95% CI: 1.75–2.79]). Here, PTH is linked to Headache.