Stricter IHS Criteria May Underdiagnose
New Daily Persistent Headache

BY JOHN R. BELL
Elsevier Global Medical News

BOSTON (EGMN) - Many people who meet the Silberstein-Lipton criteria for new daily persistent headache would not qualify for the diagnosis under the more stringent 2004 International Headache Society criteria, according to a new analysis presented May 2 at the annual meeting of the American Academy of Neurology.

The International Headache Society (IHS) International Classification of Headache Disorders criteria exclude patients with "no more than one of photophobia, phonophobia, or mild nausea." In addition, the patient may have "neither moderate or severe nausea nor vomiting." However, the Silberstein-Lipton (SL) criteria, devised in 1994, allow such migrainous features in the diagnosis of new daily persistent headache (NDPH).

Dr. Valerie E. Dechant of Thomas Jefferson University, Philadelphia, and colleagues conducted an analysis to see what effect the IHS criteria exclusions would have. They used electronic medical records to identify 100 patients with NDPH seen at their institution, as diagnosed by the SL criteria. They divided these patients into two groups: those who also met the more restrictive IHS criteria (39 patients) and those who did not (61 patients).

The investigators found that IHS-positive subjects had a statistically significant lesser degree of headache severity as assessed on the Migraine Disability Assessment Scale (MIDAS) (56.7 vs. 101.7) and were less likely to have aura (18%) than were the IHS-negative patients (52%) - also a statistically significant difference. In addition, 21 of the 39 IHS-positive patients (54%) provided an exact day of onset, compared with 46 of the 61 IHS-negative patients (75%). Moreover, the IHS-positive patients' mean scores on the Beck Depression Inventory were lower (11.9 vs. 17.2, respectively).

Thus most of the patients who had new daily persistent headache according to the SL criteria did not have NDPH according to the IHS criteria, principally because the IHS criteria contain a lower number of migraine features, leading to lower BDI scores and less disability.

Although the IHS criteria for NDPH excluded features of migraine, they "also end up eliminating other things that are not explicitly excluded, that tend to be associated with migraine - like blurred vision, like problems with appetite." said Dr. Dechant, who presented the findings as a poster.

"Interestingly, we also found that if you met the IHS criteria, you tended to have a lower numeric score on the depression inventory of the disabilities scale [MIDAS], saying that you have . . . less sense of disability and depressive symptoms that may be associated - maybe not - with your headache. So maybe there's something fundamentally different about patients who have these migrainous features, along with the sudden onset of a headache."

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