***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: A comparison of pressure reducing properties of alternating air , static air , and water mattress overlays was conducted with 57 patients in a surgical intensive care unit . Sacral and heel pressures in both recumbent and semi-Fowler 's positions were tested for each surface using a repeated measures design . Mean pressures for the alternating air mattress were significantly higher than pressures with other surfaces , regardless of position or site . There were significant main effects for position and site , with higher pressures in the semi-Fowler 's position and at the sacral site . A significant interaction between surface , site , and position was found . Pressure sores developed in eight patients , but the incidence was not significantly different across groups . A pressure measuring device constructed from available clinical material s proved to be both sensitive and reliable . The findings suggest alternating air overlays should be avoided , and that positioning and periodic position change to reduce sacral pressures for patients requiring prolonged upper body elevation is important Background The approximately 1100 medical journals now active in China are publishing a rapidly increasing number of research reports , including many studies identified by their authors as r and omized controlled trials . It has been noticed that these reports mostly present positive results , and their quality and authenticity have consequently been called into question . We investigated the adequacy of r and omization  of clinical trials published in recent years in China to determine how many of them met acceptable st and ards for allocating participants to treatment groups . Methods The China National Knowledge Infrastructure electronic data base was search ed for reports of r and omized controlled trials on 20 common diseases published from January 1994 to June 2005 . From this sample , a subset of trials that appeared to have used r and omization methods was selected . Twenty-one investigators trained in the relevant knowledge , communication skills and quality control issues interviewed the original authors of these trials about the participant r and omization methods and related quality -control features of their trials . Results From an initial sample of 37,313 articles identified in the China National Knowledge Infrastructure data base , we found 3137 apparent r and omized controlled trials . Of these , 1452 were studies of conventional medicine ( published in 411 journals ) and 1685 were studies of traditional Chinese medicine ( published in 352 journals ) . Interviews with the authors of 2235 of these reports revealed that only 207 studies adhered to accepted methodology for r and omization and could on those grounds be deemed authentic r and omized controlled trials ( 6.8 % , 95 % confidence interval 5.9–7.7 ) . There was no statistically significant difference in the rate of authenticity between r and omized controlled trials of traditional interventions and those of conventional interventions . R and omized controlled trials conducted at hospitals affiliated to medical universities were more likely to be authentic than trials conducted at level 3 and level 2 hospitals ( relative risk 1.58 , 95 % confidence interval 1.18–2.13 , and relative risk 14.42 , 95 % confidence interval 9.40–22.10 , respectively ) . The likelihood of authenticity was higher in level 3 hospitals than in level 2 hospitals ( relative risk 9.32 , 95 % confidence interval 5.83–14.89 ) . All r and omized controlled trials of pre-market drug clinical trial were authentic by our criteria . Of the trials conducted at university-affiliated hospitals , 56.3 % were authentic ( 95 % confidence interval 32.0–81.0 ) . Conclusion Most reports of r and omized controlled trials published in some Chinese journals lacked an adequate description of r and omization . Similarly , most so called ' r and omized controlled trials ' were not real r and omized controlled trials owing toa lack of adequate underst and ing on the part of the authors of rigorous clinical trial design . All r and omized controlled trials of pre-market drug clinical trial included in this research were authentic . R and omized controlled trials conducted by authors in high level hospitals , especially in hospitals affiliated to medical universities had a higher rate of authenticity . That so many non-r and omized controlled trials were published as r and omized controlled trials reflected the fact that peer review needs to be improved and a good practice guide for peer review including how to identify the authenticity of the study urgently needs to be developed Six hundred patients at risk for pressure sores were r and omized in either a control group or one of two experimental groups placed on alternating-pressure air-mattresses and water-mattresses . The groups remained comparable throughout the 10-day study period . Twenty-one patients from the control group developed decubitus ulcers , compared with 7 in each of the other groups . Patient and ward personnel opinions on the acceptability of the three types of mattresses were registered Objective To explore pressure area related pain as a predictor of category ≥2  pressure  ulcer ( PU ) development . Design Multicentre prospect i ve cohort study . Setting UK hospital and community setting s. Participants inclusion Consenting acutely ill patients aged ≥18 years , defined as high risk ( Braden bedfast/chairfast AND completely immobile/very limited mobility ; pressure area related pain or ; category 1 PU ) . Exclusion Patients too unwell , unable to report pain , 2 or more category ≥2 PUs . Follow-up Twice weekly for 30 days . Primary and secondary outcome measures Development and time to development of one or more category ≥2 PUs . Results Of 3819 screened , 1266 were eligible , 634 patients were recruited , 32 lost to follow-up , providing a 602 analysis population . 152 ( 25.2 % ) developed one or more category ≥2 PUs . 464 ( 77.1 % ) patients reported pressure area related pain on a healthy , altered or category 1 skin site of whom 130 ( 28.0 % ) developed a category ≥2 PU compared with 22 ( 15.9 % ) of those without pain . Full stepwise variable selection was used throughout the analyses . ( 1 ) Multivariable logistic regression model to assess 9 a priori factors : presence of category 1 PU ( OR=3.25 , 95 % CI ( 2.17 to 4.86 ) , p<0.0001 ) , alterations to intact skin ( OR=1.98 , 95 % CI ( 1.30 to 3.00 ) , p=0.0014 ) , pressure area related pain ( OR=1.56 , 95 % CI ( 0.93 to 2.63 ) , p=0.0931 ) . ( 2 ) Multivariable logistic regression model to account for overdispersion : presence of category 1 PU ( OR=3.20 , 95 % CI ( 2.11 to 4.85 ) , p<0.0001 ) , alterations to intact skin ( OR=1.90 , 95 % CI ( 1.24 to 2.91 ) , p=0.0032 ) , pressure area related pain ( OR=1.85 , 95 % CI ( 1.07 to 3.20 ) , p=0.0271 ) , pre-existing category 2 PU ( OR=2.09 , 95 % CI ( 1.35 to 3.23 ) , p=0.0009 ) , presence of chronic wound ( OR=1.66 , 95 % CI ( 1.06 to 2.62 ) , p=0.0277 ) , Braden activity ( p=0.0476 ) . ( 3 ) Accelerated failure time model : presence of category 1 PU ( AF=2.32 , 95 % CI ( 1.73 to 3.12 ) , p<0.0001 ) , pressure area related pain ( AF=2.28 , 95 % CI ( 1.59 to 3.27 ) , p<0.0001 ) . ( 4 ) 2-level r and om-intercept logistic regression model : skin status which comprised 2 levels ( versus healthy skin ) ; alterations to intact skin ( OR=4.65 , 95 % CI ( 3.01 to 7.18 ) , p<0.0001 ) , presence of category 1 PU ( OR=17.30 , 95 % CI ( 11.09 to 27.00 ) , p<0.0001 ) and pressure area related pain ( OR=2.25 , 95 % CI ( 1.53 to 3.29 ) , p<0.0001 ) . Conclusions This is the first study to assess pain as a predictor of category ≥2 PU development . In all 4 models , pain emerged as a risk factor associated with an increased probability of category ≥2 PU development In the GRADE approach , r and omized trials start as high- quality evidence and observational studies as low- quality evidence , but both can be rated down if most of the relevant evidence comes from studies that suffer from a high risk of bias . Well-established limitations of r and omized trials include failure to conceal allocation , failure to blind , loss to follow-up , and failure to appropriately consider the intention-to-treat principle . More recently recognized limitations include stopping early for apparent benefit and selective reporting of outcomes according to the results . Key limitations of observational studies include use of inappropriate controls and failure to adequately adjust for prognostic imbalance . Risk of bias may vary across outcomes ( e.g. , loss to follow-up may be far less for all-cause mortality than for quality of life ) , a consideration that many systematic review s ignore . In deciding whether to rate down for risk of bias -- whether for r and omized trials or observational studies -- authors should not take an approach that averages across studies . Rather , for any individual outcome , when there are some studies with a high risk , and some with a low risk of bias , they should consider including only the studies with a lower risk of bias BACKGROUND  Pressure ulcers represent a major burden to patients , carers and the healthcare system , affecting approximately 1 in 17 hospital and 1 in 20 community patients . They impact greatly on an individual 's functional status and health-related quality of life . The mainstay of pressure ulcer prevention practice is the provision of pressure redistribution support surfaces and patient repositioning . The aim of the PRESSURE 2 study is to compare the two main mattress types utilised within the NHS : high-specification foam and alternating pressure mattresses , in the prevention of pressure ulcers . METHODS / DESIGN PRESSURE 2 is a multicentre , open-label , r and omised , double triangular , group sequential , parallel group trial . A maximum of 2954 ' high-risk ' patients with evidence of acute illness will be r and omised on a 1:1 basis to receive either a high-specification foam mattress or alternating-pressure mattress in conjunction with an electric profiling bed frame . The primary objective of the trial is to compare mattresses in terms of the time to developing a new Category 2 or above pressure ulcer by 30 days post end of treatment phase . Secondary endpoints include time to developing new Category 1 and 3 or above pressure ulcers , time to healing of pre-existing Category 2 pressure ulcers , health-related quality of life , cost-effectiveness , incidence of mattress change and safety . Validation objectives are to determine the responsiveness of the Pressure Ulcer Quality of Life-Prevention instrument and the feasibility of having a blinded endpoint assessment using photography . The trial will have a maximum of three planned analyses with unequally spaced review s at event-driven coherent cut-points . The futility boundaries are constructed as non-binding to allow a decision for stopping early to be overruled by the Data Monitoring and Ethics Committee . DISCUSSION The double triangular , group sequential design of the PRESSURE 2 trial will provide an efficient design through the possibility of early stopping for demonstrating either superiority , inferiority of mattresses or futility of the trial . The trial optimises the potential for producing robust clinical evidence on the effectiveness of two commonly used mattresses in clinical practice earlier than in a conventional design . TRIAL REGISTRATION IS RCT N01151335 . Registered on 14 May 2013 . Protocol version : 5.0 , date d 25 September 2015 Trial sponsor : Clare Skinner , Faculty Head of Research Support , University of Leeds , Leeds , LS2 9JT ; 0113 343 4897 ; C.E.Skinner@leeds.ac.uk Abstract Objective To compare whether differences exist between alternating pressure overlays and alternating pressure mattresses in the development of new pressure ulcers , healing of existing pressure ulcers , and patient acceptability . Design Pragmatic , open , multicentre , r and omised controlled trial . Setting 11 hospitals in six NHS trusts . Participants 1972 people admitted to hospital as acute or elective patients . Interventions Participants were r and omised to an alternating pressure mattress ( n = 982 ) or an alternating pressure overlay ( n = 990 ) . Main outcome measures The proportion of participants developing a new pressure ulcer of grade 2 or worse ; time to development of new pressure ulcers ; proportions of participants developing a new ulcer within 30 days ; healing of existing pressure ulcers ; and patient acceptability . Results Intention to treat analysis found no difference in the proportions of participants developing a new pressure ulcer of grade 2 or worse ( 10.7 % overlay patients , 10.3 % mattress patients ; difference 0.4 % , 95 % confidence interval - 2.3 % to 3.1 % , P = 0.75 ) . More overlay patients requested change owing to dissatisfaction ( 23.3 % ) than mattress patients ( 18.9 % , P = 0.02 ) . Conclusion No difference was found between alternating pressure mattresses and alternating pressure overlays in the proportion of people who develop a pressure ulcer . Trial registration IS RCT N BACKGROUND Pressure ulcers frequently occur in hospitalised patients . The prevalence of pressure ulcers grade 2 
    Output:
    
This is the first network meta- analysis of the effects of support surfaces for pressure ulcer prevention .
Powered active air-surfaces probably reduce pressure ulcer incidence , but are probably less comfortable than st and ard hospital surfaces .