[Prognostic factors related to recurrence after extended thymectomy in patients with myasthenia gravis]

To identify the recurrence-related factors in patients with myasthenia gravis (MG) after extended thymectomy.

Followed up was conducted on 271 MG patients, 127 males and 146 females, aged 31 (4-57), who underwent extended thymectomy for 18-84 months. Post-operational pathological examination showed 32 cases of thymoma and 239 cases of diseases other than thymoma. After operation the patients were treated with pyridostigmine only or combined with adrenocortical hormone. The relevant factors of the 135 patients with relapse were evaluated: sex, Osserman classification, age while being operated on, duration of preoperative period, pathologic type of thymus, use of steroid before operation, infection after operation, whether only taking anticholinesterase drugs after operation, use of steroid immediately after operation, stopping medicine or decreasing the dose of medicine within 1-3 months after remission of symptoms.

COX univariate analysis revealed that failure to take steroid immediately after operation (OR = 2.914, P = 0.000), infection after operation (OR = 3.441, P = 0.000), only taking anticholinesterase drugs after operation (OR = 5.947, P = 0.000), and immediately stopping medicine use or decreasing the dose of medicine within 1-3 months after the remission of symptoms (OR = 2.242, P = 0.000) were prognostic factors for postoperative recurrence. On the other hand, multivariate logistic regression analysis revealed that infection after operation (OR = 47.63, P = 0.000), only taking anticholinesterase drugs after operation (OR = 62.38, P = 0.000), and stopping medicine or decreasing the dose of medicine 1-3 months after remission of symptoms (OR = 32.76, P = 0.000) were independent influencing factors of recurrence after operation.

Post-operative infection, only taking pyridostigmine, and stopping medicine too early are independent factors of postoperative relapse. Regular treatment and timely use of adrenocortical hormone decrease the recurrence after operation.