Headache coding and diagnostic-related groups: a survey of one year's admissions to a neurological department.

In 1995, the introduction of Diagnostic Related Groups (DRGs) within the Italian National Health Service (NHS) significantly changed the mode of payment for hospital admissions. The ICD-IX system is the fundamental instrument by which to identify various clinical entities; however, its codes still refer to an old international classification of diseases. Headache disorders are now diagnosed according to the new classification of the International Headache Society, and their recognition using ICD-IX codes appears to be increasingly inadequate. We evaluated 1-year admissions for "headache" in our Department of Neurology according to the new DRG system, and paid particular attention to the problems related to compilation of the patient discharge schedule. The most common mistakes affecting the definition of DRGs and the admission costs for the NHS were also examined.