***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND Therapy with antibiotics influences recovery only in selected cases of COPD exacerbations . We evaluated the efficacy and safety of procalcitonin guidance compared to st and ard therapy with antibiotic prescriptions in patients experiencing exacerbations of COPD . METHODS A total of 208 consecutive patients requiring hospitalization for COPD exacerbation were r and omized at the index exacerbation to procalcitonin-guided or st and ard antibiotic therapy . Patients receiving procalcitonin-guided therapy were treated with antibiotics according to serum procalcitonin levels ; st and ard-therapy patients received antibiotics according to the attending physician . The primary outcome was the antibiotic exposure at the index exacerbation and the subsequent antibiotic requirement for COPD exacerbation within 6 months . Secondary outcomes were clinical recovery , symptom scores , length of hospitalization , ICU stay , death , lung function , exacerbation rate , and time to next exacerbation . RESULTS At the index exacerbation , procalcitonin guidance reduced antibiotic prescription ( 40 % vs 72 % , respectively ; p < 0.0001 ) and antibiotic exposure ( relative risk [ RR ] , 0.56 ; 95 % confidence interval [ CI ] , 0.43 to 0.73 ; p < 0.0001 ) compared to st and ard therapy . Moreover , procalcitonin guidance at the index exacerbation allowed a significant sustained reduction in total antibiotic exposure for up to 6 months ( RR , 0.76 ; 95 % CI , 0.64 to 0.92 ; p = 0.004 ) . Clinical outcome and improvement in FEV(1 ) at 14 days and 6 months did not differ between groups . Within 6 months , the exacerbation rate ( 0.62 vs 0.64 , respectively ) , the rehospitalization rate ( 0.21 vs 0.24 , respectively ) , and mean ( + /- SD ) time to the next exacerbation ( 70.0 + /- 46.1 vs 70.4 + /- 51.9 days , respectively ; p = 0.523 ) were similar in both groups . CONCLUSIONS Procalcitonin guidance for exacerbations of COPD offers a sustained advantage over st and ard therapy in reducing antibiotic use for up to 6 months with a number-needed-to-treat of 3 BACKGROUND The value of azithromycin for treatment of acute bronchitis is unknown , even though this drug is commonly prescribed . We have investigated this question in a r and omised , double-blind , controlled trial . METHODS Adults diagnosed with acute bronchitis , without evidence of underlying lung disease , were r and omly assigned  azithromycin ( n=112 ) or vitamin C  ( n=108 ) for 5 days ( total dose for each 1.5 g ) . All individuals were also given liquid dextromethorphan and albuterol inhaler with a spacer . The primary outcome was improvement in health-related quality of life at 7 days ; an important difference was defined as 0.5 or greater . Analysis was by intention to treat . FINDINGS The study was stopped by the data -monitoring and safety committee when 220 patients had been recruited . On day 7 , the adjusted difference in health-related quality of life was small and not significant ( difference 0.03 [ 95 % CI -0.20 to 0.26 ] , p=0.8 ) . 86 ( 89 % ) of 97 patients in the azithromycin group and 82 ( 89 % ) of 92 in the vitamin C group had returned to their usual activities by day 7 ( difference 0.5 % [ -10 % to 9 % ] , p>0.9 ) . There were no differences in the frequency of adverse effects ; three patients in the vitamin C group discontinued the study medicine because of perceived adverse effects , compared with none in the azithromycin group . Most patients ( 81 % ) reported benefit from the albuterol inhaler . INTERPRETATION Azithromycin is no better than low-dose vitamin C for acute bronchitis . Further studies are needed to identify the best treatment for this disorder BACKGROUND Reduced duration of antibiotic treatment might contain the emergence of multidrug-resistant bacteria in intensive care units . We aim ed to establish the effectiveness of an algorithm based on the biomarker procalcitonin to reduce antibiotic exposure in this setting . METHODS In this multicentre , prospect i ve , parallel-group , open-label trial , we used an independent , computer-generated r and omisation sequence to r and omly assign patients in a 1:1 ratio to procalcitonin ( n=311 patients ) or control ( n=319 ) groups ; investigators were masked to assignment before , but not after , r and omisation . For the procalcitonin group , antibiotics were started or stopped based on predefined cut-off ranges of procalcitonin concentrations ; the control group received antibiotics according to present guidelines . Drug selection and the final decision to start or stop antibiotics were at the discretion of the physician . Patients were expected to stay in the intensive care unit for more than 3 days , had suspected bacterial infections , and were aged 18 years or older . Primary endpoints were mortality at days 28 and 60 ( non-inferiority analysis ) , and number of days without antibiotics by day 28 ( superiority analysis ) . Analyses were by intention to treat . The margin of non-inferiority was 10 % . This trial is registered with Clinical Trials.gov , number NCT00472667 . FINDINGS Nine patients were excluded from the study ; 307 patients in the procalcitonin group and 314 in the control group were included in analyses .  Mortality of patients in the procalcitonin group seemed to be non-inferior to those in the control group at day 28 ( 21.2 % [ 65/307 ] vs 20.4 % [ 64/314 ] ; absolute difference 0.8 % , 90 % CI -4.6 to 6.2 ) and day 60 ( 30.0 % [ 92/307 ] vs 26.1 % [ 82/314 ] ; 3.8 % , -2.1 to 9.7 ) . Patients in the procalcitonin group had significantly more days without antibiotics than did those in the control group ( 14.3 days [ SD 9.1 ] vs 11.6 days [ SD 8.2 ] ; absolute difference 2.7 days , 95 % CI 1.4 to 4.1 , p<0.0001 ) . INTERPRETATION A procalcitonin-guided strategy to treat suspected bacterial infections in non-surgical patients in intensive care units could reduce antibiotic exposure and selective pressure with no apparent adverse outcomes . FUNDING Assistance Publique-Hôpitaux de Paris , France , and Brahms , Germany CONTEXT In previous smaller trials , a procalcitonin ( PCT ) algorithm reduced antibiotic use in patients with lower respiratory tract infections ( LRTIs ) . OBJECTIVE To examine whether a PCT algorithm can reduce antibiotic exposure without increasing the risk for serious adverse outcomes . DESIGN , SETTING , AND PATIENTS A multicenter , noninferiority , r and omized controlled trial in emergency departments of 6 tertiary care hospitals in Switzerl and with an open intervention of 1359 patients with mostly severe LRTIs r and omized between October 2006 and March 2008 . INTERVENTION Patients were r and omized to administration of antibiotics based on a PCT algorithm with predefined cutoff ranges for initiating or stopping antibiotics ( PCT group ) or according to st and ard guidelines ( control group ) . Serum PCT  was measured locally in each hospital and instructions were Web-based . MAIN OUTCOME MEASURES Noninferiority of the composite adverse outcomes of death , intensive care unit admission , disease-specific complications , or recurrent infection requiring antibiotic treatment within 30 days , with a predefined noninferiority boundary of 7.5 % ; and antibiotic exposure and adverse effects from antibiotics . RESULTS The rate of overall adverse outcomes was similar in the PCT and control groups ( 15.4 % [ n = 103 ] vs 18.9 % [ n = 130 ] ; difference , -3.5 % ; 95 % CI , -7.6 % to 0.4 % ) . The mean duration of antibiotics exposure in the PCT vs control groups was lower in all patients ( 5.7 vs 8.7 days ; relative change , -34.8 % ; 95 % CI , -40.3 % to -28.7 % ) and in the subgroups of patients with community-acquired pneumonia ( n = 925 , 7.2 vs 10.7 days ; -32.4 % ; 95 % CI , -37.6 % to -26.9 % ) , exacerbation of chronic obstructive pulmonary disease ( n = 228 , 2.5 vs 5.1 days ; -50.4 % ; 95 % CI , -64.0 % to -34.0 % ) , and acute bronchitis ( n = 151 , 1.0 vs 2.8 days ; -65.0 % ; 95 % CI , -84.7 % to -37.5 % ) . Antibiotic-associated adverse effects were less frequent in the PCT group ( 19.8 % [ n = 133 ] vs 28.1 % [ n = 193 ] ; difference , -8.2 % ; 95 % CI , -12.7 % to -3.7 % ) . CONCLUSION In patients with LRTIs , a strategy of PCT guidance compared with st and ard guidelines result ed in similar rates of adverse outcomes , as well as lower rates of antibiotic exposure and antibiotic-associated adverse effects . TRIAL REGISTRATION is rct n.org Identifier : IS RCT N95122877 Introduction Patients with severe acute exacerbations of asthma often receive inappropriate antibiotic treatment . We aim ed to determine whether serum procalcitonin ( PCT ) levels can effectively and safely reduce antibiotic exposure in patients experiencing exacerbations of asthma . Methods In this r and omized controlled trial , a total of 216 patients requiring hospitalization for severe acute exacerbations of asthma were screened for eligibility to participate and 169 completed the 12-month follow-up visit . Patients were r and omized to either PCT-guided ( PCT group ) or st and ard ( control group ) antimicrobial therapy . In the control group , patients received antibiotics according to the attending physician ’s discretion ; in the PCT group , patients received antibiotics according to an algorithm based on serum PCT levels . The primary end point was antibiotic exposure ; secondary end points were clinical recovery , length of hospital stay , clinical and laboratory parameters , spirometry , number of asthma exacerbations , emergency room visits , hospitalizations and need for corticosteroid use due to asthma . Results PCT guidance reduced antibiotic prescription ( 48.9 % versus 87.8 % , respectively ; P < 0.001 ) and antibiotic exposure ( relative risk , 0.56 ; 95 % confidence interval , 0.44 to 0.70 ; P < 0.001 ) compared to st and ard therapy . There were no significant differences in clinical recovery , length of hospital stay or clinical , laboratory and spirometry outcomes in both groups . Number of asthma exacerbations , emergency room visits , hospitalizations and need for corticosteroid use due to asthma were similar during the 12-month follow-up period . Conclusion A PCT-guided strategy allows antibiotic exposure to be reduced in patients with severe acute exacerbation of asthma without apparent harm . Trial registration Chinese Clinical Trial Register ChiCTR-TRC-12002534 ( registered 26 September 2012 Objective : For patients in intensive care units , sepsis is a common and potentially deadly complication and prompt initiation of appropriate antimicrobial therapy improves prognosis . The objective of this trial was to determine whether a strategy of antimicrobial spectrum escalation , guided by daily measurements of the biomarker procalcitonin , could reduce the time to appropriate therapy , thus improving survival . Design : R and omized controlled open-label trial . Setting : Nine multidisciplinary intensive care units across Denmark . Patients : A total of 1,200 critically ill patients were included after meeting the following eligibility requirements : expected intensive care unit stay of ≥24 hrs , nonpregnant , judged to not be harmed by blood sampling , bilirubin < 40 mg/dL , and triglycerides < 1000 mg/dL ( not suspensive ) . Interventions : Patients were r and omized either to the “ st and ard-of-care-only arm , ” receiving treatment according to the current international guidelines and blinded to procalcitonin levels , or to the “ procalcitonin arm , ” in which current guidelines were supplemented with a drug-escalation algorithm and intensified diagnostics based on daily procalcitonin measurements . Measurements and Main Results : The primary end point was death from any cause at day 28 ; this occurred for 31.5 % 
    Output:
    
This up date d meta- analysis of individual participant data from 12 countries shows that the use of procalcitonin to guide initiation and duration of antibiotic treatment results in lower risks of mortality , lower antibiotic consumption , and lower risk for antibiotic-related side effects .
Results were similar for different clinical setting s and types of ARIs , thus supporting the use of procalcitonin in the context of antibiotic stewardship in people with ARIs .