how many patients were diagnosed with crnry athrscl natve vssl within the same month since 5 years ago after the diagnosis of rheumatoid arthritis?
select count( distinct t1.subject_id ) from ( select admissions.subject_id, diagnoses_icd.charttime from diagnoses_icd join admissions on diagnoses_icd.hadm_id = admissions.hadm_id where diagnoses_icd.icd9_code = ( select d_icd_diagnoses.icd9_code from d_icd_diagnoses where d_icd_diagnoses.short_title = 'crnry athrscl natve vssl' ) and datetime(diagnoses_icd.charttime) >= datetime(current_time,'-5 year') ) as t1 join ( select admissions.subject_id, diagnoses_icd.charttime from diagnoses_icd join admissions on diagnoses_icd.hadm_id = admissions.hadm_id where diagnoses_icd.icd9_code = ( select d_icd_diagnoses.icd9_code from d_icd_diagnoses where d_icd_diagnoses.short_title = 'rheumatoid arthritis' ) and datetime(diagnoses_icd.charttime) >= datetime(current_time,'-5 year') ) as t2 on t1.subject_id = t2.subject_id where t1.charttime < t2.charttime and datetime(t1.charttime,'start of month') = datetime(t2.charttime,'start of month')