instruction: specify the number of patients who had icd9 code 8960 and treated with base drug
response: SELECT COUNT(DISTINCT demographic.subject_id) FROM demographic INNER JOIN procedures ON demographic.hadm_id = procedures.hadm_id INNER JOIN prescriptions ON demographic.hadm_id = prescriptions.hadm_id WHERE procedures.icd9_code = "8960" AND prescriptions.drug_type = "BASE"