Analysis of factors associated with brittle response in patients with Parkinson's disease

The brittle response (BR) in patients with Parkinson's disease (PD) refers to a special type of levodopa-induced dyskinesia (LID). This study aimed to describe the clinical characteristics of BR patients and to analyze the associated risk factors.

A retrospective study was conducted to analyze the data of 97 patients with PD. Patients were divided into a BR group and a non-brittle response (NBR) group. Demographic and clinical data, motor symptoms, and non-motor symptoms of the two groups were assessed.

Among 97 PD patients, 11 were in the BR group and 86 were in the NBR group. The proportion of female patients was 72.7% and 38.3%, respectively, in the BR and NBR groups (P < 0.05). Compared to NBR patients, BR patients had relatively low body weight, low BMI, long disease duration, high levodopa equivalent daily dosage (LEDD), and high levodopa dose per weight (P < 0.05). The BR group had significantly higher scores of UPDRS (II, III, and IV) (P < 0.05). But no difference was found in the UPDRS I, emotional state, cognitive status, and accompanied by REM sleep behavior disorder (RBD) (P> 0.05). Multivariate logistic regression analysis showed that BR patients had lower body weight and higher levodopa dose per weight.

BR is associated with being female, low body weight, low BMI, long disease duration, high LEDD, and high levodopa dose per weight. Body weight and levodopa dose per body weight are independent risk factors for BR.