Cost Analysis of Imipenem-cilastatin Versus Clindamycin with Tobramycin in the Treatment of Acute Intra-abdominal Infection

Clinical effectiveness of imipenem/cilastatin (I/C) versus tobramycin with clindamycin (T + C) in treatment of patients presenting with suspected acute intra-abdominal infection was assessed in a multicentre randomised clinical trial conducted during 1985 to 1986. The principal finding was a lower incidence of treatment failure among patients in the I/C arm (p = 0.043). We now report results of retrospective analysis of hospital treatment costs during an episode of infection incurred by patients enrolled in the trial. Treatment costs (in 1989 US dollars) were calculated from a hospital perspective, using an intention-to-treat analysis. Among 161 patients with low illness severity (APACHE II less than or equal to 14) the mean cost for the episode of care was $US7038 in the I/C arm versus $US8404 for the T + C regimen; the difference was not statistically significant (p = 0.40). For 93 more severely ill patients (APACHE II score greater than 14) the mean cost for the I/C arm was $US19 985 versus $US16 582 for the T + C regimen; the difference was not statistically significant (p = 0.36). Multiple regression analysis, controlling for patient demographics and study site, showed that the cost of the episode was positively associated with the severity of illness (p less than 0.01) and presence of malnutrition (p < 0.01), but that the total cost of the episode of infection was not statistically different for the 2 drug regimens (p = 0.45).