Measurement of adult antimicrobial drug use in tertiary care hospital using defined daily dose and days of therapy.

Widespread overuse and inappropriate use of antimicrobial drugs continues to fuel an increase in antimicrobial resistance and leads to consequent treatment complications and increased healthcare costs. In the present study we aimed to describe antimicrobial drug consumption and predictors and to identify potential targets for antimicrobial stewardship. This was a prospective observational study conducted at adult medicine wards of tertiary care teaching hospital over the period of five months. Antimicrobial drug consumption was measured using days of therapy per 1000 patient days and defined daily dose per 1000 patient days. Additionally, predictors of multiple antimicrobial prescribing were also analyzed. Seven hundred thirty patients were screened and 550 enrolled, receiving 1,512 courses of antimicrobial therapy, mainly intravenously (66%). Most frequently prescribed agents were artesunate (13%), ceftriaxone (11%) and metronidazole (10.5%). Overall consumption was 1,533 days of therapy per 1000 patient days and was mainly attributed to antibiotics (98.3%) for empirical therapy (50%). Median days of antimicrobial drugs prescribing were 3 (inter quartile range 2-5). Most commonly consumed antimicrobials were ceftriaxone (31%, 248.8 g) and artesunate (26%, 29 g). Antimicrobials contributed to 72.5% expense of the total incurred. Multivariate analysis reveals that younger patients (≥45 years) (odds ratio: 1.59, 95% CI 1.14-2.21) were more likely and absence of comorbidities (odds ratio: 0.58, 95% CI 0.42-0.79) and shorter hospital stay (≥6 days)(odds ratio: 0.44, 95% CI 0.32-0.60) were associated with less likelihood of prescribing multiple antimicrobial drugs. Estimating antimicrobial drugs use by defined daily dose method will remain open to criticism because the prescribed dosage is not often in agreement with the "usual" daily dose, which depends on location of and susceptibility of pathogenic organisms and metabolic status of the patient.