calculate the number of patients diagnosed with ocl vrtb art wo infrct since 1 year ago.
select count( distinct admissions.subject_id ) from admissions where admissions.hadm_id in ( select diagnoses_icd.hadm_id from diagnoses_icd where diagnoses_icd.icd9_code = ( select d_icd_diagnoses.icd9_code from d_icd_diagnoses where d_icd_diagnoses.short_title = 'ocl vrtb art wo infrct' ) and datetime(diagnoses_icd.charttime) >= datetime(current_time,'-1 year') )