Evaluation of peripheral neuropathy in lower limbs of patients with rheumatoid arthritis and its relation to fall risk

BACKGROUND: Rheumatoid Arthritis (RA) is a chronic disabling systemic disease characterized by joint inflammation, and extra-articular manifestations, including peripheral neuropathy, a condition that can be associated with changes in muscle strength, proprioception and postural balance contributing for the risk of falls. The objective of this study is to analyze the incidence of peripheral neuropathy in patients with RA and its association with the occurrence of falls. METHODS: Patients were assessed by an electroneuromyography (ENMG) exam and by a questionnaire on accidental falls occurrence in the previous 12 months. They were also assessed on balance by the Short Physical Performance Battery (SPPB), functionality by the Health Assessment Questionnaire (HAQ), disease activity by the Disease Activity Score (DAS-28), neuropathic pain by the Questionnaire for the Diagnosis of Neuropathic Pain (DN4), and cutaneous sensitivity of the feet by the monofilament testing of Semmes–Weinstein. Monthly calls on falls were made in the subsequent six months. Data analysis was performed using the Shapiro–Wilk test for normality and Spearman, Chi-square, and T-student correlation tests, with a significant P level ≤ 0.05. RESULTS: A sample of 33 patients were evaluated. The incidence of peripheral neuropathy was 48.5%, of which 68.7% were axonal and 31.3% myelinic. The sensorimotor type was present in 64.7%, motor in 17.6%, and sensorial in 11.7% of the cases. Neuropathy was associated to balance (P = 0.026), neuropathic pain (P = 0.016), deep tendon reflexes absence (P = 0,049), altered skin sensitivity of the feet (P = 0.029) and fear of falling (P = 0.001). No association was found between peripheral neuropathy and age, gender, disease activity, or functionality. No significant association was found between peripheral neuropathy and occurrence of falls, in a 12-month retrospective and 6-month prospective evaluation. CONCLUSION: Peripheral neuropathy has a high incidence in patients with RA, and is related to neuropathic pain, altered postural balance, but not to the occurrence of falls.