Objective: To explore the relationship between sociodemographic, clinical, and neurophysiological variables and health-related quality of life (HR-QOL) of patients with phantom limb pain (PLP).
Methods: This is a cross-sectional analysis of a previous clinical trial. Univariate and multivariate linear and logistic regression analyses were used to model the predictors of HR-QOL. We utilized a sequential modeling approach with increasing adjustment levels, controlling for age and sex, and other relevant clinical variables (time since amputation, level of amputation, and pain). HR-QOL was assessed by the SF-36 Health Survey and its 8 subdomains.
Results: We analyzed baseline data from 92 patients with lower-limb amputations. They were mostly male (63%), 45.2 ± 15.6 years, with a mean time since amputation of 82.7 ± 122.4 months, and an overall SF-36 score of 55.9 ± 21.5. We found an association between intracortical facilitation (ICF) in the affected hemisphere, gabapentin usage, and HR-QOL. ICF is a predictor of better HRQOL, whereas gabapentin usage was associated with a poorer HR-QOL, with the main model explaining 13.4% of the variance in the outcome. For the SF-36 subdomains, ICF was also a positive predictor for social functioning, bodily pain, and vitality, while medication usage was associated with lower scores in mental health, general health perception, bodily pain, and vitality.
Conclusion: We found firsthand 2 new independent predictors of HR-QOL in individuals with PLP, namely, the neurophysiological metric ICF and gabapentin usage. These results highlight the role of the motor cortex excitability in the HR-QOL and stress the need for treatments that favor the neuroplastic adaptation after amputation, for which ICF may be used as a possible marker.
Keywords: health-related quality of life; lower limb amputation; phantom limb pain; predictors.
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