Headache coding and diagnostic-related groups: a survey of one year's admission 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 admission. The ICD-IX system is the fondamental instrument by which to identify various clinical entities; however , its codes still refer to an old international classification of diseases. The most common mistakes affecting the definition of DRGs and the admission costs for the NHS were also examined.