Predictors of relapse in patients with medication overuse headache in Shanghai: A retrospective study with a 6-month follow-up.

Medication overuse headache (MOH) has a high relapse rate and disease heterogeneity. This study aimed to determine the predictors of MOH relapse in patients through a 6-month follow-up in Shanghai. In this retrospective study, patients diagnosed with MOH from June 2016 to June 2017 were recruited and followed up for 6 months after withdrawal treatment in Renji Hospital in Shanghai. Patients' information was obtained using headache questionnaires. Follow-up was conducted via telephone interview. Patients were divided into relapse group and no-relapse group according to the outcomes after 6 months. This study enrolled 124 outpatients with MOH at baseline. 102 patients completed the follow up and were analysis finally. Demographics and clinical characteristics were compared between the relapse (n = 39, 38.24%) and no-relapse (n = 63, 61.76%) group. Binary logistic regression analysis was performed, and two variables emerged as significant predictors of relapse before withdrawal; the headache frequency (day/month) was higher in the relapse group than in the no-relapse group [odds ratio (OR) 1.107, p = 0.008]. Furthermore, patients administered analgesics of ≥ 2 units per headache day had a higher risk of relapse [odds ratio (OR) 2.791, p = 0.038]. Headache frequency and analgesics units per headache day before withdrawal may be independent predictors of MOH relapse. Therefore, early identification of high-risk groups and enhancing patients' management could contribute to improving the prognosis of MOH.