Drug-related problems in elective surgical inpatients: A retrospective study

Patients with drug-related problems are at high risk for perioperative complications. The study aimed to determine the prevalence, number, characteristics, clinical significance and the involved drugs of drug-related problems in inpatients, who were admitted to elective surgery, as well as their burden of comorbidity.

The study design was a retrospective, observational study across nine different surgical sites. Patients at admission for elective surgery with  ≥ 1 drug-related problem, a hospital stay of  ≥ 24 h and at age  ≥ 18 years were included. The outcomes of interest were the prevalence and nature of drug-related problems, assessed by pharmacists at hospital admission. The Pharmaceutical Network Europe classification V9.1, the Hatoum scale of clinical significance, the Anatomical-Therapeutic-Chemical classification scheme of the World Health Organization were engaged to categorize drug-related problems and their clinical significance. The Charlson Comorbidity Index was applied to assess the comorbidity of participants.

The final data set included 11,176 elective surgical inpatients. Of these, a sample of 284 (2.54%) patients was analysed. It was found that 9.89% of the patients showed at least one drug-related problem (average 1.43, SD 0.7). Major causes were drug-drug interactions (30.3%) and supra-therapeutic doses (18.0%). Most drug-related problems were referred to a prescriber for intervention (61.3%). Eighty-two percent of drug-related problems were rated as clinically significant. Cardiovascular drugs were of major concern. Participants' most common comorbidities were tumour diagnosis (34%), diabetes mellitus with end organ damage (26%) and peripheral vascular diseases (19%).

Although the prevalence of drug-related problems in this diverse study population was low, drug-related problems were of great importance in terms of their cause and clinical significance. Patients with drug-related problems showed a moderate burden of physiological illness. Study results suggest a need to identify exposed patients with drug-related problems.