***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 Supporting 21st century health care and the practice of evidence -based medicine ( EBM ) requires ubiquitous access to clinical information and to knowledge-based re sources to answer clinical questions . Many questions go unanswered , however , due to lack of skills in formulating questions , crafting effective search strategies , and accessing data bases to identify best levels of evidence . Methods This r and omized trial was design ed as a pilot study to measure the relevancy of search results using three different interfaces for the PubMed search system . Two of the search interfaces utilized a specific framework called PICO , which was design ed to focus clinical questions and to prompt for publication type or type of question asked . The third interface was the st and ard PubMed interface readily available on the Web . Study subjects were recruited from interns and residents on an inpatient general medicine rotation at an academic medical center in the US . Thirty-one subjects were r and omized to one of the three interfaces , given 3 clinical questions , and asked to search PubMed for a set of relevant articles that would provide an answer for each question . The success of the search results was determined by a precision score , which compared the number of relevant or gold st and ard articles retrieved in a result set to the total number of articles retrieved in that set . Results Participants using the PICO templates ( Protocol A or Protocol B ) had higher precision scores for each question than the participants who used Protocol C , the st and ard PubMed Web interface . ( Question 1 : A = 35 % , B = 28 % , C = 20 % ; Question 2 : A = 5 % , B = 6 % , C = 4 % ; Question 3 : A = 1 % , B = 0 % , C = 0 % ) 95 % confidence intervals were calculated for the precision for each question using a lower boundary of zero . However , the 95 % confidence limits were overlapping , suggesting no statistical difference between the groups . Conclusion Due to the small number of search es for each arm , this pilot study could not demonstrate a statistically significant difference between the search protocol s. However there was a trend towards higher precision that needs to be investigated in a larger study to determine if PICO can improve the relevancy of search results Purpose In diabetics , elevated preoperative hemoglobin A1c ( HbA1c ) levels are associated with increased complication rates after cardiac surgery . While many non-diabetics also have elevated HbA1c , the relationship with outcome in these patients is not well understood . Therefore , in a cohort of non-diabetic patients , we tested the hypothesis that preoperative HbA1c is associated with early mortality risk after cardiac surgery . Methods In this retrospective observational study , we accessed data from a prospect ively collected quality assurance data base for a cohort of 1,474 non-diabetic elective cardiac surgery patients with documented preoperative HbA1c levels . The relationship of HbA1c with death within 30 days of surgery was examined using logistic regression modeling . Acute kidney injury and infection were similarly assessed using multivariable linear and logistic regression . Results Thirty-one percent of patients ( n = 456 ) had elevated HbA1c values ( > 6.0 % ) . Patients with elevated HbA1c had higher fasting and peak intraoperative blood glucose values . Also , an elevated HbA1c level was independently associated with increased 30-day mortality ( odds ratio 1.53 per percent increase [ 1.24 - 1.91 ] ; P = 0.0005 ) . This relationship persisted even after “ borderline ” diabetics were excluded . Furthermore , acute kidney injury was associated with elevated baseline HbA1c ( P = 0.01 ) . No association was found between HbA1c and postoperative infection risk ( P = 0.48 ) . Conclusion In non-diabetics , an elevated preoperative HbA1c level ( > 6.0 % ) is independently associated with significantly greater early mortality risk after elective cardiac surgery . Our findings suggest that HbA1c may have value as a screening tool to identify high-risk non-diabetic cardiac surgery patients .RèsumèObjectifChez les diabétiques , des niveaux élevés d’hémoglobine A1c ( HbA1c ) préopératoire sont associés à une incidence accrue de complications après une chirurgie cardiaque . Alors que nombre de personnes non diabétiques ont également des niveaux élevés de HbA1c , la relation entre ces niveaux et le devenir de ces patients demeure mal comprise . Pour cette raison , dans une cohorte de patients non diabétiques , nous avons testé l’hypothèse selon laquelle la HbA1c préopératoire est associée à un risque de mortalité précoce après une chirurgie cardiaque . MéthodeDans cette étude observationnelle rétrospective , nous avons utilisé des données tirées d’une base de données d’assurance de la qualité récoltées de façon prospect i ve et portant sur une cohorte de 1474 patients non diabétiques devant subir une chirurgie cardiaque non urgente et do nt les niveaux préopératoires de HbA1c étaient documentés . La relation entre les niveaux de HbA1c et le décès dans les 30 jours suivant la chirurgie a été examinée à l’aide d’un modèle de régression logistique . Les lésions rénales aiguës et les infections ont été évaluées de la même façon à l’aide de modèles de régression logistique et linéaire multivariée . RésultatsTrente et un pour cent des patients ( n = 456 ) présentaient des valeurs de HbA1c élevées ( > 6,0 % ) . Chez les patients présentant des valeurs de HbA1c élevées , la glycémie était plus élevée à jeun et atteignait des valeurs maximales plus gr and es pendant l’opération . De plus , un niveau élevé de HbA1c était associé de façon indépendante à une mortalité accrue à 30 jours ( rapport de cotes 1,53 par augmentation de pour cent [ 1,24 - 1,91 ] ; P = 0,0005 ) . Cette relation est demeurée apparente même après l’exclusion des diabétiques « limite » du calcul . En outre , les lésions rénales aiguës étaient associées à des valeurs de HbA1c de base élevées ( P = 0,01 ) . Aucune association n’a été découverte entre la HbA1c et le risque d’infection postopératoire ( P = 0,48 ) . Conclusion Chez les personnes non diabétiques , un niveau préopératoire élevé de HbA1c ( > 6,0 % ) est associé de façon indépendante à un risque de mortalité précoce significativement plus élevé après une chirurgie cardiaque non urgente . Nos résultats suggèrent que le niveau de HbA1c pourrait être utile comme outil de dépistage afin d’identifier les patients de chirurgie cardiaque non diabétiques mais à risque élevé As the U.S. population ages , major surgical procedures are being performed in elderly patients with increasing frequency ( 1 ) , but few data are available to guide preoperative risk stratification . Several studies have described correlates of cardiac morbidity and mortality in patients undergoing noncardiac surgery  ( 2 - 8 ) , but the number of elderly patients in most series has been small . Furthermore , few data are available on noncardiac complications , the overall complication rate , and length of stay . We describe the influence of age on perioperative complication and mortality rates in a large cohort of patients undergoing noncardiac surgery .  As discussed elsewhere , age was not an independent correlate of major cardiac complications in this cohort ( 7 ) . This analysis tests the hypothesis that advanced age is a correlate of the overall rate of complications , after adjustment for functional status . Methods Patients All patients 50 years of age or older who underwent major nonemergent noncardiac procedures at Brigham and Women 's Hospital , Boston , Massachusetts , from 18 July 1989 to 28 February 1994 were eligible for the study . Major noncardiac procedures were defined as those with an expected length of stay of 2 or more days . Procedures were electively scheduled or were performed nonemergently during inpatient admissions . Eligibility criteria included the ability to speak English and adequate cognitive function to give informed consent . The enrollment and clinical data collection protocol s were approved by the institutional review board of Brigham and Women 's Hospital . The full study protocol included preoperative interviews by clinical study personnel ( physicians or research nurses ) . Of the 4315 patients who provided informed consent to participate , 621 ( 14.4 % ) did not provide consent before surgery for the serial interview portion of the study , which included interviews 1 and 6 months after surgery . Patients who were not interviewed before surgery were not excluded on the basis of age or clinical status , but solely according to the availability of study personnel . Data Collection The data collection protocol is described elsewhere ( 7 , 9 , 10 ) . In brief , patients who provided informed consent to the full study protocol underwent preoperative evaluation by clinical investigators ( physicians or research nurses ) using a structured data form . These evaluations included detailed medical histories , physical examinations , and laboratory tests . For patients who did not undergo this evaluation because they could not be approached or because they declined participation in the interview portion of the study , we obtained clinical data from the structured evaluation by the anesthesiologist found in the medical record . This data source was also used to obtain American Society of Anesthesiologists classification for all patients . Hence , prospect ively recorded clinical data were available for all patients . Consenting patients agreed to postoperative sampling of creatine kinase and , if total creatine kinase levels were elevated , measurement of creatine kinaseMB immediately after surgery , at 8 p.m. on the evening of surgery , and on the next two mornings . In all other enrolled patients , creatine kinaseMB was measured according to the physician 's orders . Among all participants , the mean ( SD ) number of cardiac enzyme sample s obtained was 4.0 2.2 . Electrocardiography was performed in the recovery room and on the first , third , and fifth postoperative days if the patient remained hospitalized . The Charlson Comorbidity Index , a weighted comorbidity score based on the number and the severity of 16 selected medical diseases , was used to quantify the burden of medical comorbid conditions ( 11 ) . The mean number of other common comorbid conditions in this population was calculated for all patients . Preoperative functional status was assessed in 3890 patients by performing structured interviews using the  Specific Activity Scale , an ordinally scaled , four-class instrument based on metabolic expenditure in various personal care , housework , occupational , and recreational activities ( 12 , 13 ) . This group included 196 patients who consented to preoperative interviews but did not consent to the full study protocol , including long-term follow-up . Classification of Outcomes The occurrence of major cardiac events postoperatively was classified by a single review er who was blinded to preoperative clinical data and who evaluated only postoperative clinical information , including cardiac enzyme measurements , electrocardiograms , and clinical events . Myocardial infa rct ion was diagnosed on the basis of creatine kinaseMB levels and electrocardiographic findings ( 10 ) . Major cardiac complications were unstable angina ( postoperative typical chest pain associated with ischemic electrocardiographic changes ) , myocardial infa rct ion , cardiogenic pulmonary edema , documented ventricular tachycardia , ventricular fibrillation or primary cardiac arrest , and sustained complete heart block requiring pacemaker . Major noncardiac events were pulmonary embolism documented by autopsy , angiography , or a high-probability ventilationperfusion scan ; respiratory failure requiring intubation for more than 2 days or reintubation ; noncardiogenic pulmonary edema ; lobar pneumonia confirmed by chest radiography and requiring antibiotic therapy ; acute renal failure requiring dialysis ; or cerebrovascular accident with new neurologic deficit . In-hospital mortality was also recorded , and the combined end point of major cardiac or noncardiac complications or death was used in these analyses . Statistical Analysis To evaluate the impact of age on postoperative complications , we performed analyses in which age was considered as a continuous variable and as four categories ( 50 to 59 years , 60 to 69 years , 70 to 79 years , and 80 years ) . Because age was not linearly associated with the risk for outcomes , categorized age variables are used throughout this report . Univariate correlations between clinical characteristics and age category were analyzed by using the chi-square test and the Fisher exact test for categorical variables and a t-test or Wilcoxon test for continuous variables . Because several clinical and laboratory variables are associated with age and because it is difficult to exclude the association of age with the event of interest , we included all relevant clinical variables in the multivariate analysis . Logistic regression analysis was used to determine the independent association of age with postoperative complications while controlling for the presence of comorbid conditions , sex , ethnicity , functional status as measured by Specific Activity Scale class , type of procedure , and preoperative laboratory data . Patients for whom data on selected variables were missing were excluded from the model . Clinical ly relevant variables from the regression model were analyzed for potential interactions , and potentially significant interaction terms were considered in the regression models . A two-sided P value less than 0.05 was considered statistically significant in all analyses . Linear regression models were used to estimate the independent variation in length of stay attributable to age , controlling for sex , ethnicity , preoperative clinical characteristics , American Society of Anesthesiologists classification , type of procedure , postoperative events , and in-hospital mortality . The logarithmic transformation of length of stay was used because of the non-normal distribution of this 
    Output:
    
Conclusions and relevance Based on the limited available evidence , suboptimal pre-operative HbA1c levels in patients with no prior history of diabetes predict post-operative complications and represent a potentially modifiable risk factor