Analysis of risk factors for medication-overuse headache relapse: a clinic-based study in China

BACKGROUND Medication overuse headache (MOH) is the third most prevalent headache type after migraine and tension-type headache. A large number of studies on the long-term prognosis have shown that MOH has a high relapse rate after treatment. Although MOH relapse-related risk factors have been reported, no related research has been performed in China. Therefore, the purpose of this study was to analyze and evaluate the risk factors for MOH relapse in China. METHODS Eighty-six out-patients of Shandong Provincial Hospital who were initially diagnosed with MOH, and who had successful withdrawal treatment within 2 months, were chosen from March 2012 to July 2013. All subjects were followed up by the investigators of this study. Of the 86 subjects, 27 who had relapsed were compared with 59 who had not relapsed (i.e. the controls). Based on a standardized questionnaire, a database was created (with Microsoft Excel 2010). The data, which included 38 indexes, were analyzed by univariate analysis with chi-square test, Fisher's exact test, t-test, or paired rank test. The statistically correlated (P<0.05) variables were chosen as the independent variables, thereby enabling the calculation of the non-conditional multivariate stepwise logistic regression. RESULTS The independent risk factors for medication-overuse headache relapse were determined as headache frequency before drug withdrawal, duration of primary headache, and headache frequency after drug withdrawal. CONCLUSION Headache frequency before drug withdrawal, duration of primary headache, and headache frequency after drug withdrawal may be the independent risk factors for MOH relapse in China.