Predictors of neuropathic dysesthetic pain occurrence and chronification in multiple sclerosis (2-year prospective study).

BACKGROUND: Patients with multiple sclerosis (MS) are a high-risk group for neuropathic pain.

OBJECTIVE: to investigate predictors of neuropathic dysesthetic pain (NDP) occurrence and chronification in patients with MS during a 2-year observation period.

METHODS: After the exclusion criteria application and signing of informed consent, we recruited in the study 241 patients among which 23 patients prematurely stopped participating in the study. During the 2-year observation period, new NDP was diagnosed on the PainDETECT questionnaire (>18). Patients with newly diagnosed NDP were examined at baseline, in 1, 3, and 6 months depending on pain duration. The socio-demographic, neuropsychological, cognitive, sleep quality, and clinical characteristics of patients were evaluated at the beginning of the study and updated at baseline examination in cases of newly diagnosed NDP.

RESULTS: Over a 2-year observation period, NDP occurred in 34 patients (15.6%). Out of 34 cases of newly diagnosed NDP, in 20 cases (58.9%) pain became chronic (lasting longer than 3 months). In the Cox proportional hazards multifactorial model, progressive types of MS were an independent predictor of NDP occurrence (hazard ratio 2.60; 95% confidence interval, 1.30-5.18; p=0.01). In the multifactorial logistic regression analysis, subclinical depressive disorders (according to Hospital Anxiety and Depression Scale) were identified as an independent predictor of NDP chronification (odds ratio 7.14; 95% confidence interval, 1.12-45.59; p=0.04).

CONCLUSIONS: In MS predictors of NDP occurrence are progressive types of MS, whereas predictors of NDP chronification are subclinical depressive disorders.