***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: Prognosis studies are investigations of future events or the evaluation of associations between risk factors and health outcomes in population s of patients ( 1 ) . The results of such studies improve our underst and ing of the clinical course of a disease and assist clinicians in making informed decisions about how best to manage patients . Prognostic research also informs the design of intervention studies by helping define subgroups of patients who may benefit from a new treatment and by providing necessary information about the natural history of a disorder ( 2 ) . There has recently been a rapid increase in the use of systematic review methods to synthesize the evidence on research questions related to prognosis . It is essential that investigators conducting systematic review s thoroughly appraise the method ologic quality of included studies to be confident that a study 's design , conduct , analysis , and interpretation have adequately reduced the opportunity for bias ( 3 , 4 ) . Caution is warranted , however , because inclusion of method ologically weak studies can threaten the internal validity of a systematic review ( 4 ) . This follows abundant empirical evidence that inadequate attention to biases can cause invalid results and inferences ( 5 - 9 ) . However , there is limited consensus on how to appraise the quality of prognosis studies ( 1 ) . A useful framework to assess bias in such studies follows the basic principles of epidemiologic research ( 10 , 11 ) . We focus on 6 areas of potential bias : study participation , study attrition , prognostic factor measurement , confounding measurement and account , outcome measurement , and analysis . The main objectives of our review of review s are to describe methods used to assess the quality of prognosis studies and to describe how well current practice s assess potential biases . Our secondary objective is to develop recommendations to guide future quality appraisal , both within single studies of prognostic factors and within systematic review s of the evidence . We hope this work facilitates future discussion and research on biases in prognosis studies and systematic review s. Methods Literature Search and Study Selection We identified systematic review s of prognosis studies by search ing MEDLINE ( 1966 to October 2005 ) using the search strategy recommended by McKibbon and colleagues ( 12 ) . This strategy combines broad search terms for systematic review s ( systematic review .mp ; meta- analysis .mp ) and a sensitive search strategy for prognosis studies ( cohort , incidence , mortality , follow-up studies , prognos * , predict * , or course ) . We also search ed the reference lists of included review s and method ologic papers to identify other relevant publications . We restricted our search to English- language publications . One review er conducted the search and selected the studies . Systematic review s , defined as review s of published studies with a comprehensive search and systematic selection , were included if they assessed the method ologic quality of the included studies by using 1 or more explicit criteria . We excluded studies if they were meta-analyses of independent patient data only , if their primary goal was to investigate the effectiveness of an intervention or specific diagnostic or screening tests , or if they included studies that were not done on humans . Data Extraction and Synthesis Individual items included in the quality assessment of the systematic review s were recorded as they were reported in the publication ( that is , the information that would be available to readers and future review ers ) . We review ed journal Web sites and contacted the authors of the systematic review s for additional information when authors made such an offer in their original papers . When review s assessed different study design s by using different sets of quality items , we extracted only those items used to assess cohort studies . We constructed a comprehensive list of distinct items that the review s used to assess the quality of their included studies . The full text of each review was screened . All items used by the review authors to assess the quality of studies were extracted into a computerized spreadsheet by 1 review er . Two experienced review ers , a clinical epidemiologist and an epidemiologist , independently synthesized the quality items extracted from the prognosis review s to determine how well the systematic review s assessed potential biases . We did this in 3 steps : 1 ) identified distinct concepts or domains addressed by the quality items ; 2 ) grouped each extracted quality item into the appropriate domain or domains ; and 3 ) identified the domains necessary to assess potential biases in prognosis studies . We then used this information to assess how well the review s ' quality assessment included items from the domains necessary to assess potential biases . After completing each of the first 3 steps , the review ers met to attempt to reach a consensus . The consensus process involved each review er presenting his or her observations and results , followed by discussion and debate . A third review er was available in cases of persistent disagreement or uncertainty . In the first step , all domains addressed by the quality items were identified . The first review er iteratively and progressively defined the domains as items were extracted from the included review s. The second review er defined domains from a r and om list of all extracted quality items . Limited guidance was provided to the review ers so that their assessment s and definitions of domains would be independent . The review ers agreed on a final set of domains that adequately and completely defined all of the extracted items . In the second step , review ers independently grouped each extracted item into the appropriate domains . Review ers considered each extracted item by asking , What is each particular quality item addressing ? or What are the review 's authors getting at with the particular quality assessment item ? . Items were grouped into the domain or domains that best represented the concepts being addressed . For example , the extracted items at least 80 % of the group originally identified was located for follow-up and follow-up was sufficiently complete or does n't jeopardize validity were each independently classified by both review ers as assessing the domain completeness of follow-up adequate , whereas the extracted item quantification and description of all subjects lost to follow-up was classified as assessing the domain completeness of follow-up described . In the third step , we identified the domains necessary to assess potential biases . Each review er considered the ability of the identified domains to adequately address , at least in part , 1 of the following 6 potential biases : 1 ) study participation , 2 ) study attrition , 3 ) prognostic factor measurement , 4 ) confounding measurement and account , 5 ) outcome measurement , and 6 ) analysis . Domains were considered to adequately address part of the framework if information garnered from that domain would inform the assessment of potential bias . For example , both review ers judged that the identified domain study population represents source population or population of interest assessed potential bias in a prognosis study , whereas the domain research question definition did not , although the latter is an important consideration in assessing the inclusion of studies in a systematic review . Finally , on the basis of our previous ratings , we looked at whether each review included items from the domains necessary to assess the 6 potential biases . We calculated the frequency of systematic review s by assessing each potential bias and the number of review s that adequately assessed bias overall . From this systematic synthesis , we developed recommendations for improving quality appraisal in future systematic review s of prognosis studies . We used Microsoft Access and Excel 2002 ( Microsoft Corp. , Redmond , Washington ) for data management and SAS for Windows , version 9.1 ( SAS Institute , Inc. , Cary , North Carolina ) for descriptive statistics . Role of the Funding Sources The funding sources , the Canadian Institutes of Health Research , the Canadian Chiropractic Research Foundation , the Ontario Chiropractic Association , and the Ontario Ministry of Health and Long Term Care , did not have a role in the collection , analysis , or interpretation of the data or in the decision to su bmi t the manuscript for publication . Results We identified 1384 potentially relevant articles . Figure 1 shows a flow chart of studies that were included and excluded . Figure 2 shows the number of review s identified by year of publication . We excluded 131 systematic review s of prognosis studies that did not seem to include any quality assessment of the included studies ; this represented 44 % of prognosis review s. We included 163 review s of prognosis studies in our analysis ( 13 - 175 ) . The most common topics were cancer ( 15 % ) , musculoskeletal disorders and rheumatology ( 13 % ) , cardiovascular ( 10 % ) , neurology ( 10 % ) , and obstetrics ( 10 % ) . Other review s included a wide range of health and health care topics . Sixty-three percent of the review s investigated the association between a specific prognostic factor and a particular outcome ; the remainder investigated multiple prognostic factors or models . The number of primary studies included in each systematic review ranged from 3 to 167 ( median , 18 [ interquartile range , 12 to 31 ] ) . A complete description of the included review s is available from the authors on request . Figure 1 . Flow diagram of inclusion and exclusion criteria of systematic review s. Figure 2 . Number of systematic review s of prognosis studies identified over time . Quality Items One hundred fifty-three review s provided adequate detail to allow extraction of quality items . Eight hundred eighty-two distinct quality items were extracted from the review s. Most review s developed their own set of quality items , with only a few applying criteria from previous review s. Most quality items Objective This study was design ed to examine whether a brief hospital intervention design ed to alter patients ’ perceptions about their myocardial infa rct ion ( MI ) would result in a better recovery and reduced disability . Design In a prospect i ve r and omized study , 65 consecutive patients with their first MI aged were assigned to receive an intervention design ed to alter their perceptions about their MI or usual care from rehabilitation nurses . Patients were assessed in hospital before and after the intervention and at 3 months after discharge from hospital . Results The intervention caused significant positive changes in patients ’ views of their MI . Patients in the intervention group also reported they were better prepared for leaving hospital ( p < .05 ) and subsequently returned to work at a significantly faster rate than the control group ( p < .05 ) . At the 3-month follow-up , patients in the intervention group reported a significantly lower rate of angina symptoms than control subjects ( 14.3 vs. 39.3 , p < .03 ) . There was no significant differences in rehabilitation attendance between the two groups . Conclusions An in-hospital intervention design ed to change patients ’ illness perceptions can result in improved functional outcome after MI OBJECTIVES The purpose of this study was to investigate the effects of a cognitive-behavioral psoriasis symptom management programme ( PSMP ) on patient-held perceptions about their condition and patients ' use of self-reported coping strategies , and to examine the influence of alexithymia scores at induction on response to treatment . DESIGN Age- and sex-matched case-controlled prospect i ve study . METHODS A total of 40 patients with psoriasis were treated in the PSMP  , and an age- and sex-matched cohort received  st and ard pharmacological care only . The Illness Perception Question  naire was used to assess patients ' beliefs about illness identity , time-line , consequences , cure/control and perceptions of the cause of their psoriasis . Participants also completed the  COPE question naire  and the  Toronto Alexithymia Scale ( TAS-20 ) . RESULTS Results suggested that at 6-month follow-up , patients who chose the PSMP showed significant reductions in illness identity ( the frequency and severity of symptoms that patients associate with their condition ) , the strength of belief in severity of consequences of their illness , and their attributions for emotional causes of their psoriasis . Perceptions about the anticipated course of the disease ( time-line ) , its cure or controllability , ideas about physical agents of causation , and coping strategies did not differ between PSMP patients or controls at 6-week or 6-month follow-up . Alexithymia had no effect on response to treatment . Regression analyses demonstrated the importance of both participation in the PSMP and demographic/ clinical history variables in accounting for significant variance in illness-perception-change scores . CONCLUSION The findings are generally supportive of multivariate models of intervention , but the lack of a demonstrated effect of the intervention on coping may have implication s for both the assessment of coping in psoriasis and the nature of psychological interventions proposed for its management According to Leventhal 's Self-Regulatory Model of Illness , patients have ideas and action plans related to the management of their disease . The aim of this study is to examine whether ideas and action plans relating to hypertension change as a result of general practitioner 's ( GP 's ) discussing them during consultation , and whether these changed ideas and actions plans affect adherence . The study employed an experimental design , highlighting three conditions : ( 0 ) care-as-usual consultation ; ( 1 ) discussing patient 's ideas about their disorder ; and ( 2 ) discussing patient 's action plans .  Ten GP-trainees performed care-as-usual consultations  , were subsequently assigned to a training in either Condition 1 or 2 , and performed the trained conversations .  Hundred and eight patients with hypertension were consecutively assigned to the conditions , and completed question naires a week before , immediately after the consultation , and 1 month later . The training result ed in two new , feasible and different types of conversations that managed to affect some of the patient 's ideas and action plans . It is concluded that the study provided GPs with a tool to discuss illness representations and actions plan of patients with hypertension . Implication s for the management of hypertension adherence in primary care are discussed A prospect i ve investigation is described which sought to test the role of illness cognitions in determining patient responses to a  surgical intervention for osteoarthritis .  Illness cognitions were assessed amongst a consecutive sample of patients with osteoarthritis of the knee or hip prior to undergoing joint replacement surgery .  Functional activity and depression were assessed pre-operatively , and at 3 and 9 months post surgery . At pre-operative assessment , functional activity and depression were univariately associated with the perceived consequences of osteoarthritis . Path analyses using longitudinal data demonstrated that illness cognitions had predictive value in explaining outcomes . Depression at 3 months was associated with higher pre-operative perceived control beliefs suggesting that patients who have high control pre-operatively may be at risk for temporary depressed mood in the immediate aftermath of surgery . This effect was not maintained at 9 months . Depression at 9 months was lower amongst patients who were more active at 3 months , who did not attribute their condition to wear and tear and who had higher expectations of surgery . Functional activity at 9 months was higher amongst those who did not attribute their condition to growing older and who perceived more control over symptoms . Socio-demographic variables 
    Output:
    
Conclusions The limited number of studies in this review suggests that illness perceptions play a role in the work participation of patients with somatic diseases or complaints , although it is not clear how strong this relationship is and which illness perception dimensions are most useful .