PROSPECTIVE AUDIT OF COSTS AND OUTCOME OF AMINOGLYCOSIDE TREATMENT AND OF THERAPY FOR GRAM-NEGATIVE BACTEREMIA

The aims of this study were to audit the monitoring of aminoglycoside treatment to develop a method for measurement of the cost and outcome of treatment, and to assess the accuracy of a previously published sep sis score to predict cost and outcome. Measurements of costs and outco mes were also made for all patients (n = 85) with Gram-negative bacter aemia. Of these, 40 received an aminoglycoside and an additional 215 p atients received aminoglycosides for other indications (total aminogly coside patients 255; total patients 300). There were no interpretable assays for 82 (32%) of the aminoglycoside patients and only 33/173 (19 %) patients assayed had first peak serum concentrations within the rec ommended range of 8-10 mg/L. Median costs of aminoglycoside treatment were pound 599 in neutropenic patients, pound 471 in ICU patients and pound 185 in other patients. In the bacteraemic patients, median costs of aminoglycoside regimens (pound 278) were higher than for non-amino glycoside regimens (pound 97). Death in hospital was twice as common i n bacteraemic patients (20% versus 10%) and there was a stepwise incre ase in rate of mortality with sepsis scores. Treatment costs were mark edly higher in patients who failed to respond to initial treatment, th e mean difference in cost was pound 418 per patient (95% CI pound 89-7 47). Sepsis scores only explained 2.6% of the variance in treatment co sts, and 22 patients with zero sepsis scores received prolonged course s of iv antibiotic treatment at an average cost of pound 209 per patie nt. In conclusion, aminoglycoside regimens rarely conformed to accepte d standards of care and treatment failure was associated with markedly increased treatment costs. Three readily measurable indicators of adv erse outcome were identified (death in hospital, change of iv treatmen t and readmission within 2 weeks of discharge) and all were related to initial severity of illness as measured by sepsis score. The sepsis s core may prove useful for assessment of individual risk but would bene fit from further analysis to validate and possibly reduce the number o f items in the score.