***TASK***
the task is to simplify the input abstract of a biomedical literature

***INPUT***
the input is the abstract of a biomedical literature

***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature

***DOCUMENTATION***

***EXAMPLES***

Input: We identified six eligible studies in total. The six Included studies were generally of high quality, but the largest eligible study was excluded because of concerns about its validity. Study populations were statin naive, which led to a considerable loss of eligible participants. Five RCTs compared statin use with placebo or standard care. We pooled results from three studies, with a total of 178 participants, for mortality and non-fatal event outcomes. In the statin group, 7/105 (6.7%) participants died within 30 days of surgery, as did 10/73 (13.7%) participants in the control group. Only one death in each group was from cardiovascular causes, with an incidence of 0.95% in statin participants and 1.4% in control participants, respectively. All deaths occurred in a single study population, and so effect estimates were derived from one study only. The risk ratio (RR) of all-cause mortality in statin users showed a non-significant decrease in risk (RR 0.73, 95% CI 0.31 to 1.75). For cardiovascular death, the risk ratio was 1.05 (95% CI 0.07 to 16.20). Non-fatal MI within 30 days of surgery was reported in three studies and occurred in 4/105 (3.8%) participants in the statin group and 8/73 (11.0%) participants receiving placebo, for a non-significant decrease in risk (RR 0.47, 95% CI 0.15 to 1.52). Several studies reported muscle enzyme levels as safety measures, but only three (with a total of 188 participants) reported explicitly on clinical muscle syndromes, with seven events reported and no significant difference found between statin users and controls (RR 0.94, 95% CI 0.24 to 3.63). The only participant-reported outcome was nausea in one small study,with no significant difference in risk between groups. Two studies compared different doses of atorvastatin, with a total of 145 participants, but reported data were not sufficient to allow us to determine the effect of higher doses on any outcome. Evidence was insufficient to allow review authors to conclude that statin use resulted in either a reduction or an increase in any of the outcomes examined. The existing body of evidence leaves questions about the benefits of perioperative use of statins for vascular surgery unanswered. Widespread use of statins in the target population means that it may now be difficult for researchers to undertake the large RCTs needed to demonstrate any effect on the incidence of postoperative cardiovascular events. However, participant-reported outcomes have been neglected and warrant further study.
Output:

In July 2012 we searched medical databases for controlled trials of participants who had undergone aortic or arterial surgery and were randomly assigned to either statins or placebo (or standard care). Many vascular surgery patients are already taking statins; therefore we also included trials that randomly assigned participants to different doses of statin. Statin treatment should have been started any time between the decision to operate and performance of the operation and continued for at least 48 hours after the operation. We wanted to investigate the effect of this short-term statin therapy on the risk of death and cardiovascular events such as heart attack and stroke within 30 days of surgery. We also considered adverse effects of statins such as muscle pain. We found five studies that compared participants receiving statins with a control treatment or with placebo, but only three of these reported outcomes could be combined in the meta-analyses. These three studies were of high quality but studied only 178 participants in total. This means that evidence was insufficient to allow review authors to determine whether statins improved patient outcomes after surgery. We were also not able to establish whether any adverse effects such as muscle pain were associated with statin use. We found that two studies had compared different doses of atorvastatin, but evidence was insufficient to determine whether any benefits or risks were associated with using a higher dose. Given the limited quantity of data obtained from randomized controlled trials, further studies are required to allow investigators to gather better information about whether prescribing statins around the time of vascular surgery can improve outcomes. However, widespread use of statins in patients before they need surgery may make these studies impracticable.