A study of representativeness of subjects in clinical trials of antidepressants in China

Objective To investigate the representativeness of patients participating in clinical trials of antidepressants in China, and explore factors that affect the representativeness of sample. Methods Outpatients or inpatients with major depressive disorder(MDD)who came to depression treatment center of Beijing Anding Hospital, Capital Medical University seeking for treatment were consecutively screened. The MINI-International Neuropsychiatric Interview and the HAMD17were used for diagnostic assessment and severity evaluating. A questionnaire was designed to investigate patients' willingness to participate in drug clinical trials. Common exclusion criteria used in clinical trials of antidepressants were applied to screen MDD patients to determin the proportion of patients who would be eligible for a clinical trial. Results 302 patients were consecutively screened and 50 of them rejected our interview. Data were collected from 252 patients, whose mean age was (40.5±13.1) years when being screened, including 173 female and 79 male, 203 outpatients and 49 inpatients. 57.5% (145/252)of the patients had no willing to participate in clinical trials, and 73.8% (186/252) were excluded by at least one exclusion. There were only 35(13.9%, 35/252) patients who were finally eligible to participate in clinical trials. Conclusions Subjects participated in antidepressant trials represent a minority of patients with MDD in clinical practice. Exclusion criteria and patients' willingness to participate in a drug clinical trial are two main factors affecting the representativeness of sample. Key words: Antidepressive agents; Clinical trial; Representativeness of sample; Generalizability