Cohort study for evaluation of dose omission without justification in a teaching general hospital in Bahia, Brazil

Int J Qual Health Care. 2016 Jun;28(3):288-93. doi: 10.1093/intqhc/mzw016. Epub 2016 Feb 11.


Objective: To evaluate the incidence of medication errors due to dose omissions and the reasons for non-administration of medications.

Design: A cohort study blinded to the nursing staff was conducted for 5 consecutive days to evaluate administration of prescribed medications to selected inpatients.

Setting: A major academic teaching hospital in Brazil.

Participants: Dispensed doses to patients in medical and surgical wards.

Main outcome measures: Doses returned to pharmacy were evaluated to identify the rate of dose omission without a justification for omission.

Results: Information was collected from 117 patients in 11 wards and 1119 doses of prescribed medications were monitored. Overall, 238/1119 (21%) dispensed doses were not administered to the patients. Among these 238 doses, 138 (58%) had no justification for not being administered. Failure in the administration of at least 1 dose occurred for 58/117 (49.6%) patients. Surgical wards had significantly more missed doses than that in medical wards (P = 0.048). The daily presence of a pharmacist in the wards was significantly correlated with lower frequency of omission errors (P = 0.019). Nervous system medications were missed more significantly than other medications (P < 0.001). No difference was noted in the omission doses in terms of route of administration.

Conclusions: High incidence of omission errors occurs in our institution. Factors such as the deficit of nursing staff and clinical pharmacists and a weak medication dispensing system, probably contributed to incidence detected. Blinding nursing staff was essential to improve the sensibility of the method for detecting omission errors.

Keywords: dose omission; medication error; patient safety.

Publication types

  • Observational Study

MeSH terms

  • Brazil
  • Hospitals, General
  • Hospitals, Teaching / statistics & numerical data*
  • Humans
  • Medication Errors / nursing*
  • Medication Errors / statistics & numerical data*
  • Medication Systems, Hospital / organization & administration
  • Medication Systems, Hospital / statistics & numerical data*
  • Pharmacists / statistics & numerical data*
  • Pharmacy Service, Hospital / organization & administration
  • Single-Blind Method