Influence Factors Of Postoperative Outcomes: A Cohort Study And A Meta-analysis

Background and objectiveEach year over 310 million patients undergo surgical treatment worldwide.Estimates of reported hos-pital mortality vary from 1 to 4%.Although many surgical procedures are uneven-ful,a proportion of patients will develop postoperative complications that may reduce their long-term survival and quality of life.The survival of patients who develop post-operative complications varies between hospitals,indicating both the potential and need to improve clinical outcomes.There may be many components to a valid and safe peri-operative care pathway,but effective recognition of high-risk surgical patients and potential treatment interventions commonly are regarded as important methods for improving complex postoperative outcomes.Epidemiological evidence show that patient comorbidities,involving anemia,have an effect on increased incidence rates of death and complication in surgical practice.Pre-operative anemia is not an unnormal laboratory value merely,but a potential preventable and identifiable risk for surgical morbidity and mortality.Although in surgical practice preoperative anemia is common,still it is frequently ignored.Some retrospective reports have suggested that preoperative anemia has an effect on postoperative mortality and morbidity,especially in some high-risk populations.However,such data have been limited by single center or conducted in specific population such as elderly cases and emergency population without stratification.Up to now,little detailed data are available to describe the association between different degrees of preoperative anemia with postoperative outcomes,in a large cohort of unselected surgical patients and especially in China.More importantly,chronic and acute anemia has different underlying conditions,but no data differentiate their impact on surgical outcomes.Our cohort study aims to describe the effect of preoperative anaemia on postoperative outcome and healthcare resource use and this will be beneficial to evaluate risks for patients.Besides,ARDS is a leading cause of post-operative hypo-xemic respiratory failure.Except lung-protective ventilation,conser-vative fluid therapy,and early neuromuscular blockade treatment,no other effective therapy exists for acute respiratory distress syndrome.Anti-platelet therapy is commonly used to reduce platelet activation and their cardiovascular benefits in patients with the risk of heart disease,stroke,and peri-pheral arterial thrombosis are widely accepted in clinical practice.However,their pleiotropic effects in high-risk surgical patients and other critically ill population yielded inconsistent results.Till now,no syntheses of conclusion have been reported to recapitulate and summarize the affect of this therapy in the above population.As we know,with the high volumes of surgery per-formed every year,even a low rate of preventable injury will be associated with a large number of modifiable deaths.Consequently,we conducted a cohort study and a meta-analysis to explore the effective recognition of high-risk surgical patients and potential treatment interventions in surgical patients.Materials and methodsCohort study: In this cohort study,one thousand nine hundred and forty-eight adult patients of our hospital from April 14 to May 13 2014 were consecutively selected.The 30-day in-hospital complications and data describing the critical care admission were collected after surgery.Multivariable logistic regression analysis was performed to understand the effects of preoperative anemia on postoperative outcomes.Data analysis was conducted through the software SPSS 19.0,P<0.05 was considered statistically significant.Meta-analysis:In order to perform this meta-analysis,seven cohort studies,retrieved from Pub Med and Embase before September 2015,involving 7030 cases of high-risk surgical patients and other critically ill patients and 1923 cases of anti-platelet users,were meta-analysed.The following data were selected: first author,publication year,study design,sample size,outcome,and definition of anti-platelet therapy.The outcome was newly developed acute respiratory distress syndrome or acute lung injury.Random-or fixed-effect models were taken for quantitative synthesis of the data.All data analyses were performed using Stata,version 12.0ResultsCohort study: We included 1948 patients in the analysis.Preoperative anemia had a high prevalence in both women and men(26.8% and 22.5%,respectively).Multivariate analysis showed that patients with Moderate-severe(OR 2.338,95%CI 1.303-4.194)and mild(OR 1.797,95%CI 1.149-2.810)anemia both are associated with an increased risk of postoperative 30-day complications.The distribution of complications in diverse causes of anaemia is different(acute 15.5%;chronic 13.9%;P<0.001).Furthermore,postoperative admission to intensive care(P=0.028)were greater in patients with anemia than in those with normal Hb concentrations.Meta-analysis: In high-risk surgical patients and other critically ill patients,anti-platelet therapy was associated with decreased newly developed ARDS/ALI(OR 0.64;95% CI,0.50–0.82;I2= 0%;P <0.001)with adjusted data and the pool OR was 0.62(95%CI 0.45–0.84;I2= 66.8%;P <0.006)with unadjusted data.Meanwhile,there may be no evidence of publication bias based on the funnels plot and Egger’s test(adjusted data,P=0.146;unadjusted data,P=0.287).ConclusionResults of our cohort study suggest that preoperative anemia,even to a mild degree,has an effect on adverse postoperative outcome.In addition,it can increase healthcare resource use.Through this meta-analysis,conclusion show that antiplatelet therapy is associated with reduced the incidence rate of newly developed ARDS/ALI in high-risk surgical patients and other critically ill patients.However,it remains unclear whether similar findings can be observed in the unselected surgical population and broad population with critical illness.