Use of the RBANS to Evaluate Cognition in Patients with Schizophrenia and Metabolic Syndrome: a Meta-Analysis of Case-Control Studies.

Schizophrenia is associated with an increased risk of metabolic syndrome (MetS), which is an important risk factor for developing cognitive impairment in the general population. A few case-control studies have explored the relationship between MetS and cognitive deficits in individuals with schizophrenia but with inconsistent findings. This meta-analysis of case-control studies was carried out to explore the association between MetS and cognitive performance in patients with schizophrenia. Only case-control studies assessing the association of cognitive function and MetS in patients with schizophrenia were identified. Cognitive function was assessed using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) scale. Six case-control studies (n = 992) comparing cognition between patients with schizophrenia with MetS (n = 426) and those without MetS (n = 566) using the RBANS were identified. Compared to patients with schizophrenia without MetS, patients with schizophrenia and MetS had significantly more impairments in RBANS total scores [standardized mean difference (SMD) = -0.26, 95% confidence interval (CI): -0.51 to -0.02; I2 = 72%; p = 0.03], immediate memory (SMD = -0.32, 95% CI: -0.54 to -0.10; I2 = 66%; p = 0.005), attention (SMD = -0.29, 95% CI: -0.56 to -0.02; I2 = 77%; p = 0.03), and delayed memory (SMD = -0.24, 95% CI: -0.46 to -0.03; I2 = 64%; p = 0.03). No group difference was found regarding visuospatial skills and language (p > 0.05). This meta-analysis found that schizophrenia patients with MetS had worse performance on certain cognitive tasks than non-MetS patients.