A bidirectional relationship between diabetes mellitus and anxiety: A systematic review and meta-analysis

Background: Due to the existence of inconsistencies in the evidence regarding the direction and extent of association between diabetes and anxiety disorders, the anxiety-diabetes comorbidity remains an issue of debate. Aim: To estimate the proportion and risk of diabetes among individuals with anxiety disorder and vice versa. Methods: A systematic review was conducted using studies retrieved from databases and grey literature, with the last database search being conducted on April 15, 2021. The methodological rigor of studies was assessed using the National Institute of Health quality assessment tool. Prevalence and effect size (ES) estimates were pooled using a random effect model. Heterogeneity was assessed using the Higgins' I2 statistical test, and subgroup analysis conducted. Results: We included 68 studies presenting data from 2,128,029 participants. The prevalence of anxiety disorders in diabetic patients was 28% (95% CI: 26%, 31%); however, subgroup analysis showed significant differences based on type of anxiety assessment scales, study location, and type of diabetes. The prevalence of diabetes among patients with anxiety disorders was 12% (95% CI: 9%, 16%). Patients with anxiety disorders were found to have a 19% higher risk of diabetes (pooled effect size (ES) = 1.19, 95% CI: 1.13, 1.26). Diabetic patients were found to have a 41% higher risk of developing anxiety disorders (ES = 1.41, 95% CI: 1.19, 1.62). Conclusions: There is a higher risk of anxiety disorders in patients with diabetes mellitus and vice versa. It is recommended to screen diabetic patients for anxiety at initial diagnosis and follow-up visits. Similarly, patients with anxiety disorders should have regular screening for diabetes.