instruction: count the number of patients who were diagnosed with acute copd exacerbation in the same hospital encounter after they were diagnosed with anemia - anemia of chronic disease since 2105.
response: SELECT COUNT(DISTINCT t1.uniquepid) FROM (SELECT patient.uniquepid, diagnosis.diagnosistime, patient.patienthealthsystemstayid FROM diagnosis JOIN patient ON diagnosis.patientunitstayid = patient.patientunitstayid WHERE diagnosis.diagnosisname = 'acute copd exacerbation' AND STRFTIME('%y', diagnosis.diagnosistime) >= '2105') AS t1 JOIN (SELECT patient.uniquepid, diagnosis.diagnosistime, patient.patienthealthsystemstayid FROM diagnosis JOIN patient ON diagnosis.patientunitstayid = patient.patientunitstayid WHERE diagnosis.diagnosisname = 'anemia - anemia of chronic disease' AND STRFTIME('%y', diagnosis.diagnosistime) >= '2105') AS t2 WHERE t1.diagnosistime < t2.diagnosistime AND t1.patienthealthsystemstayid = t2.patienthealthsystemstayid