Prevalence and predisposing factors of post-stroke complex regional pain syndrome: Retrospective case-control study

Introduction: Poststroke complex regional pain syndrome (CRPS) is an important complication in stroke survivors. The identification of factors associated with post-stroke CRPS is important for preventive measures and early diagnosis.Methods: A total of 141 first-ever stroke survivors in the subacute stage were retrospectively analyzed. Demographic data, diagnosis time, duration of hospitalization, location of brain lesion, etiology, comorbidities, and blood test findings were investigated. Clinical data included Medical Research Council (MRC) grade, Fugl-Meyer assessment (FMA), National Institute for Health Stroke Scale (NIHSS), Berg Balance Scale (BBS).Results: Among 141 patients with subacute stroke, 22 were diagnosed with CRPS, with a prevalence of 15.6 %. The mean time to diagnosis was 38.6 (+/- 16.5) days. The prevalence according to the degree of paralysis was 33.3 % in MRC grades 0 and 1, 8.6 % in grade 2, and 0 % in grade 3 or higher. The incidence rates within 1 month after stroke were 1.42 % and 22.47 % between 1 and 3 months after stroke, respectively. The independent risk factors for CRPS were hospitalization duration and FMA, NIHSS, and BBS scores. The sensitivity and specificity of the NIHSS score for predicting post-stroke CRPS were 86.4 % and 59.7 %, respectively, with an optimal cutoff value of 7.5.Conclusions: CRPS of the affected upper limb in stroke patients is associated with stroke severity, including paralysis, and the incidence increases over time during the subacute phase. Additionally, having sufficient strength to move through a full range of motion against gravity had a protective effect against CRPS.