Palgrave Handbook of Econometrics: Applied Econometrics

140 Metastatistics for the Non-Bayesian Regression Runner

Table 3.3 Initial 2004 International Headache Society classification criteria for analgesic-

overuse headache

A. Headache present on≥15 days/month with at least one of the following characteristics

and fulfilling criteria C and D:

1 bilateral

2 pressing/tightening (non-pulsating) quality

3 mild or moderate intensity

B. Intake of simple analgesics on≥15 days/month for>3 months

C. Headache has developed or markedly worsened during analgesic overuse

D. Headache resolves or reverts to its previous pattern within 2 months after discontinua-

tion of analgesics

Table 3.4 Revised ICHD-2 criteria for MOH

A. Headache present on≥15 days per month

B. Regular overuse for>3 months of one or more acute/symptomatic treatment drugs as

defined under sub forms of 8.2

1. Ergotamine, triptans, opioids, or combination analgesic medication on≥ 10
   days/month on a regular basis for≥3 months


2. Simple analgesics or any combination of ergotamine, triptans, analgesic, opioids on
   ≥15 days/month on a regular basis for≥3 months without overuse of any single
   class alone
   C. Headache has developed or markedly worsened during medication overuse

offending medication, the patient would improve. As reported in the literature,
the problem was that such a requirement vitiated using MOH as a “diagnosis” in
the traditional sense: “the problem is that medication overuse headache cannot
be diagnosed until the overuse has been discontinued and the patient has been
shown to improve. This means that when patients have it, it cannot be diagnosed.
It can be diagnosed only after the patient does not have it any more.”
After a meeting of experts in Copenhagen, this offending section (D of Table 3.3)

• requiring improvement after going off the “causal” medications – was quickly
  removed to produce a revised version (Table 3.4). Whatever their intent, however,
  this redefinition seemed to make a MOH diagnosis impossible to refute.^57 Indeed,
  it was immediately noted that “the revision [to the definition of MOH] has elimi-
  nated the need to prove that the disorder is caused by drugs, that is, the headache
  improves after cessation of medication overuse” (Ferrariet al.,2008). Although they
  suggested that “probable MOH” be introduced, their main focus was that sub-forms
  of MOH be defined for different types of medications, with opioids singled out as
  particularly problematic.^58
  The case of opioids is especially interesting since it is generally believed that
  opioid-related MOH is more worrisome and it has been argued that “sustained opi-
  oid therapy should rarely be administered to headache patients” (Saper and Lake,
  2006b). This case is also useful since it might be falsely assumed that individu-
  als doing research in this area (and supporting the idea of MOH) are incapable
  of, or not disposed to, putting hypotheses to severe testing. As noted previously,