Procalcitonin guided antibiotic therapy of acute exacerbations of asthma: a randomized controlled trial
BACKGROUND
This randomized controlled trial aimed to evaluate whether the serum procalcitonin (PCT) level can be utilized to guide the use of antibiotics in the treatment of acute exacerbations of asthma.


METHODS
A total of 293 consecutive patients with suspected asthma attacks from February 2005 to July 2010 participated in this study. 225 patients completed the study. Serum PCT levels, and other inflammatory biomarkers of all patients were measured. In addition to the standard treatment, the control group received antibiotics according to the attending physicians' discretions, while the patients in the PCT group were treated with antibiotics according to serum PCT concentrations. Antibiotics usage was strongly discouraged when the PCT concentration was below 0.1 μg/L; discouraged when the PCT concentration was between 0.1 μg/L and 0.25 μg/L; or encouraged when the PCT concentration was above 0.25 μg/L. The primary endpoint was the determination of antibiotics usage. The second endpoints included the diagnostic accuracy of PCT and other laboratory biomarkers the effectiveness of asthma control, secondary ED visits, hospital re-admissions, repeated needs for steroids or dosage increase, needs for antibiotics, WBC count, PCT levels and FEV1%.


RESULTS
At baseline, two groups were identical regarding clinical, laboratory and symptom score. Probability of the antibiotics usage in the PCT group (46.1%) was lower than that in the control group (74.8%) (χ2 = 21.97, p < 0.001. RR = 0.561, 95% CI 0.441-0.713). PCT and IL-6 showed good diagnostic significance for bacterial asthma (r = 0.705, p = 0.003). The degrees of asthma control in patients were categorized to three levels and were comparable between the two groups at the six weeks follow-up period (χ2 = 1.62, p = 0.45). There were no significant difference regarding other secondary outcomes (p > 0.05).


CONCLUSIONS
The serum PCT concentration can be used to effectively determine whether the acute asthma patients have bacterial infections in the respiratory tract, and to guide the use of antibiotics in the treatment of acute asthma exacerbations, which may substantially reduce unnecessary antibiotic use without compromising the therapeutic outcomes.


TRIAL REGISTRATION
ICTRP ChiCTR-TRC-12002534.