Treating pneumonia in critical care in the United Kingdom following failure of initial antibiotic: a cost-utility analysis comparing meropenem with piperacillin/tazobactam

Abstract
Treating patients admitted to critical care with severe pneumonia requires timely intervention with an effective antibiotic. This reduces the risk of dying of pneumonia and minimises complications associated with a prolonged stay in critical care. To compare the cost-effectiveness of meropenem 1 g/8 h with piperacillin/tazobactam 4.5 g/8 h for treating pneumonia in UK critical care. A Markov model was built to estimate lifetime costs and quality-adjusted life years (QALYs) of using meropenem versus piperacillin/tazobactam to treat severe pneumonia. Estimates of effectiveness, utility weights and costs were obtained from published sources. Probabilistic sensitivity analysis was conducted to address uncertainty in the model results. Cost of treating a patient with severe pneumonia was estimated as £19,026 with meropenem and £19,978 with piperacillin/tazobactam, respectively. QALYs gained were 4.768 with meropenem and 4.654 with piperacillin/tazobactam. Probabilistic sensitivity analysis showed meropenem to be consistently less costly and more effective than piperacillin/tazobactam. The additional efficacy of meropenem translates into more patients surviving critical care and leaving this high-cost service more quickly than if they had been treated with piperacillin/tazobactam. As meropenem is more effective and less expensive than piperacillin/tazobactam at treating patients with severe pneumonia, it is the dominant treatment option.