Simplify the following text for a Grade 9 native English-speaking person.
Original: 53 patients with OCD and 53 patients with BDD were compared on clinical features , comorbidity , family history , and demographic features .
Simplified: 53 patients with OCD and 53 patients with BDD were compared to each other in research . Clinical features , comorbidity , family history , and population features were compared between the two groups .