Prevalence of Malignant Hyperthermia and Relationship with Anesthetics in Japan Data from the Diagnosis Procedure Combination Database

Background: Malignant hyperthermia (MH) is a rare but life-threatening disease that occurs during general anesthesia. The actual prevalence of MH remains unclear, and the association between MH and various anesthetic drugs remains controversial because of a lack of universal reporting. Methods: Using the Japanese Diagnosis Procedure Combination database, we collected data of inpatients who had general anesthesia between July and December 2006-2008. Patients' age, gender, diagnoses, procedures, and the use of drugs during anesthesia, including volatile agents, muscle relaxants, and propofol, were investigated. Univariate comparisons were made to examine the relationship of each anesthetic drug or demographic factor with the occurrence of MH. Results: Of 1,238,171 surgical patients undergoing general anesthesia, we identified 17 MH patients (odds ratio: 13.7, 95% CI 7.2-20.3 per million). Only one in-hospital death was identified. Men were significantly more likely to contract MH (odds ratio: 3.49; 95% CI 1.14 -10.7; P = 0.029). No MH patient was found among 19,871 suxamethonium users. The prevalence of MH was relatively high in users of sevoflurane (odds ratio: 15.0; 95% CI 7.1-22.9 per million) and rocuronium (odds ratio: 24.3; 95% CI 4.9-43.8 per million) compared with nonusers but was not statistically significant. Conclusions: No single drug was significantly associated with the occurrence of MH. Data should be continuously compiled, and further analyses with larger numbers of cases are necessary to identify possible causative agents.