***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 included 13 studies with a total of 721 participants in the review. The studies were observational, 12 studies had only one relevant treatment arm and no control and for the one study with a control arm, very few details were given. The risk of bias was high and the certainty of evidence was graded as very low for all outcomes. Due to heterogeneity of data, meta-analysis was not performed and therefore the data were synthesised via a narrative summary. The evidence for benefit derived from PN was very low for survival and quality of life. All the studies measured overall survival and 636 (88%) of participants were deceased at the end of the study. However there were varying definitions of overall survival that yielded median survival intervals between 15 to 155 days (range three to 1278 days). Three studies used validated measures of quality of life. The results from assessment of quality of life were equivocal; one study reported improvements up until three months and two studies reported approximately similar numbers of participants with improvements and deterioration. Different quality of life scales were used in each of the studies and quality of life was measured at different time points. Due to the very low certainty of the evidence, we are very uncertain about the adverse events related to PN use. Adverse events were measured by nine studies and data for individual participants could be extracted from eight studies. This revealed that 32 of 260 (12%) patients developed a central venous catheter infection or were hospitalised because of complications related to PN. We are very uncertain whether HPN improves survival or quality of life in people with MBO as the certainty of evidence was very low for both outcomes. As the evidence base is limited and at high risk of bias, further higher-quality prospective studies are required.
Output:

The benefits of PN are uncertain as the evidence is of very low certainty, provided mainly by studies that only looked at people who received PN rather than comparing patients who received PN with those who did not. As we found no randomised controlled trials, we have included the results from 13 observational studies with a total of 721 participants. For 12 of the studies, there was only one relevant treatment group and no control group. Therefore, the results are only for people receiving PN and we have no information about those not receiving it. The average survival time for people on PN varied from three to 1278 days. Only three studies measured quality of life using a recognised measure. One study found quality of life improved and two studies found similar numbers of people both improved and deteriorated. However, the three studies monitored quality of life at different points in time and measured it in different ways. Side effects occurred in 12% of people in the eight studies that measured them. Further research is needed to find out if PN is of benefit to people with an inoperable blockage of the bowel caused by advanced cancer.