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Procalcitonin algorithms safely reduce antibiotic use

Reuters Health • The Doctor's Channel Daily Newscast

NEW YORK (Reuters Health) – Algorithms based on procalcitonin (PCT) measurements reduce the use of antibiotics without jeopardizing patient safety, according to a review of randomized clinical trials.

Furthermore, the authors of the report in the August 8/22 issue of the Archives of Internal Medicine propose a set of PCT algorithms appropriate for the US health care setting, aimed at reducing overuse of antibiotics.

Dr. Philipp Schuetz, at Harvard School of Public Health in Boston, Massachusetts, and colleagues point out that the measurement of PCT levels helps differentiate bacterial from nonbacterial Infections — because bacterial infections trigger procalcitonin synthesis, whereas nonbacterial infections and nonspecific inflammatory reactions do not.

In the current review, the team summarizes the results of 14 previous RCTs involving adults with a diagnosis of sepsis or respiratory tract infections, in which PCT levels were used to aid decisions about the initiation of antibiotic therapy and its duration.

The studies showed consistently less antibiotic prescription with PCT algorithm use versus controls, with reductions ranging from 74% to 11%. Also, the duration of antibiotic use was shorter, with decreases ranging from 55% to 15%.

This was not associated with any increase in adverse outcomes, the reviewers found. Pooled data from all 14 studies showed that overall mortality rates were not significantly different, at 7.7% in the PCT groups compared with 8.3% in the controls, for a summary odds ratio of 0.91.

The authors conclude that their review shows that the use of PCT-guide algorithms “appears to be effective at reducing use of antibiotics without sacrificing patient safety.”

Most studies of PCT-based algorithms have been conducted in Europe, Dr. Schuetz and colleagues note, and they suggest their use needs to be investigated in US populations. For such studies, they offer algorithms for three settings; i.e., low, moderate and high clinical acuity levels.

For example, for low-risk patients receiving primary care, a single PCT measurement and a cutoff ranging from less than 0.10 to less than 0.25 mcg/L appears to be appropriate and safe.

For moderate-risk patients seen in the emergency department or hospitalized with pneumonia, antibiotic therapy can be based on a PCT threshold of at least 0.25 mcg/L. Otherwise, “alternative diagnoses (eg, viral infection and pulmonary embolism) should be considered,” the algorithm indicates. Repeated PCT measurements every other day can guide further treatment.

In high-risk patients, typically admitted to the ICU, initial antibiotic therapy should not await PCT results but such measurements can indicate when discontinuation is safe.

However, the authors advise, “Algorithms for PCT use, much like those for other biomarkers, should supplement and not supplant clinical impressions.”

Arch Intern Med. 2011;171:1322-1331