***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: BACKGROUND Although headache is a common emergency department ( ED ) chief complaint , the role of the ED in the management of primary headache disorders has rarely been assessed from a population perspective . We determined frequency of ED use and risk factors for use among patients suffering severe headache . METHODS As part of the American Migraine Prevalence and Prevention study , a vali date d self-administered question naire was mailed to 24,000 severe headache sufferers , who were r and omly drawn from a larger sample constructed to be sociodemographically representative of the US population . Participants were asked a series of questions on headache management , healthcare system use , sociodemographic features , and number of ED visits  for management of headache in the previous 12 months . In keeping with the work of others , " frequent " ED use was defined as a participant 's report of 4 or more visits to the ED for treatment of a headache in the previous 12 months . Headaches were categorized into specific diagnoses using a vali date d methodology . RESULTS Of 24,000 surveys , 18,514 were returned , and 13,451 ( 56 % ) provided complete data on ED use .  Sociodemographic characteristics did not differ substantially between responders and nonresponders . Among the 13,451 responders , over the course of the previous year , 12,592 ( 94 % ) did not visit the ED at all , 415 ( 3 % ) visited the ED once , and 444 ( 3 % ) visited the ED more than once . Patients with severe episodic tension-type headache were less likely to use the ED than patients with severe episodic migraine ( OR 0.4 [ 95 % CI : 0.3 , 0.6 ] ) . Frequent ED use was reported by 1 % of the total sample or 19 % ( 95 % CI : 17 % , 22 % ) of subjects who used the ED in the previous year , although frequent users accounted for 51 % ( 95 % CI : 49 % , 53 % ) of all ED visits . Predictors of ED use included markers of disease severity , elevated depression scores , low socioeconomic status , and a predilection for ED use for conditions other than headache . CONCLUSIONS Most individuals suffering severe headaches do not use the ED over the course of a single year . The majority of ED visits for severe headache are accounted for by a small subset of all ED users . Increasing disease severity and depression are the most readily addressable factors associated with ED use OBJECTIVES To evaluate health care and financial outcomes in a population of Medicaid-insured asthmatic children after a comprehensive asthma intervention program .  DESIGN Controlled clinical trial . SETTING Pediatric allergy clinic in an urban , tertiary care children 's hospital . SUBJECTS Eighty children , 2 to 16 years old , with a history of frequent use of emergent health care services for asthma . Intervention . Children in the intervention group received asthma education and medical treatment in the setting of a tertiary care pediatric allergy clinic . An asthma outreach nurse maintained monthly contact with the families enrolled in the intervention group . OUTCOME MEASURES Emergency department ( ED ) visits , hospitalizations , and health care charges per patient in the year after enrollment . RESULTS Baseline demographics did not differ significantly between the 2 groups . In the year before the study , there were no significant differences between intervention and control children in ED visits ( mean , 3.5 per patient ) , hospitalizations ( mean,.6 per patient ) or health care charges ( $ 2969 per patient ) . During the study year , ED visits decreased to a mean of 1.7 per patient in the intervention group and 2.4 in controls , while hospitalizations decreased to a mean of.2 per patient in the intervention group and .5 in the controls . Average asthma health care charges decreased by $ 721/child/year in the intervention group and by $ 178/patient/year in the control group . CONCLUSIONS A comprehensive asthma intervention program for Medicaid-insured asthmatic children can significantly improve health outcomes while reducing health care costs.asthma education , health care outcomes , Medicaid , asthma outreach , utilization OBJECTIVES : The goal was to describe the use of the medical emergency department as a source of non-urgent medical care in order to assess unmet health care needs among its users . The specific objectives were thus to assess the proportion of emergency department visits for non-urgent medical care and to describe those who used the department for this reason . DESIGN : A cross sectional study was performed at the emergency department in two hospitals ( around 12,000 visits per year each ) . Subjects were interviewed before and after the visit using a st and ardised question naire . SETTING : The medical emergency department of two university hospitals , one in Paris and one in Besançon ( France ) . SUBJECTS : Each patient aged 15 and more attending the emergency department for a visit during 40 r and omly selected periods of 12 hours was included . MAIN OUTCOME MEASURES : A definition of urgent care was adopted before the beginning of the study . Four expert judgments were then used for each case to determine whether the reason for the visit was urgent or not . RESULTS : Altogether 594 patients in the Paris emergency department and 614 in the Besançon one were included . In Besançon , the patients were older , a general practitioner was more often cited as the regular source of care , and the percentage of subsequent hospital admission was higher than in Paris ( 71 % versus 34 % ) . The non-urgent visits were estimated to account for 35 % and 29 % of the visits in Paris and Besançon respectively . Patients using the emergency department for a non-urgent visit  were younger than other patients . More of them were unemployed , homeless , born outside of France , and without health insurance . CONCLUSIONS : Non-urgent use of the emergency department was observed in about one third of the visits . Groups using the department for primary care and /or non-urgent care were mostly young and socially fragile , with no regular source of health care . Their poor health condition suggests that there is a need for a structure providing primary care both inside and outside ' normal ' working hours CONTEXT Homeless adults , especially those with chronic medical illnesses , are frequent users of costly medical services , especially emergency department and hospital services . OBJECTIVE To assess the effectiveness of a case management and housing program in reducing use of urgent medical services among homeless adults with chronic medical illnesses . DESIGN , SETTING , AND PARTICIPANTS R and omized controlled trial conducted at a public teaching hospital and a private , nonprofit hospital in Chicago , Illinois . Participants were 407 social worker-referred homeless adults with chronic medical illnesses ( 89 % of referrals ) from September 2003 until May 2006 , with follow-up through December 2007 . Analysis was by intention-to-treat . INTERVENTION Housing offered as transitional housing after hospitalization discharge , followed by placement in long-term housing ; case management offered on-site at primary study sites , transitional housing , and stable housing sites . Usual care participants received st and ard discharge planning from hospital social workers . MAIN OUTCOME MEASURES Hospitalizations , hospital days , and emergency department visits measured using electronic surveillance , medical records , and interviews . Models were adjusted for baseline differences in demographics , insurance status , prior hospitalization or emergency department visit , human immunodeficiency virus infection , current use of alcohol or other drugs , mental health symptoms , and other factors . RESULTS The analytic sample ( n = 405 [ n = 201 for the intervention group , n = 204 for the usual care group ] ) was 78 % men and 78 % African American , with a median duration of homelessness of 30 months . After 18 months , 73 % of participants had at least 1 hospitalization or emergency department visit . Compared with the usual care group , the intervention group had unadjusted annualized mean reductions of 0.5 hospitalizations ( 95 % confidence interval [ CI ] , -1.2 to 0.2 ) , 2.7 fewer hospital days ( 95 % CI , -5.6 to 0.2 ) , and 1.2 fewer emergency department visits ( 95 % CI , -2.4 to 0.03 ) . Adjusting for baseline covariates , compared with the usual care group , the intervention group had a relative reduction of 29 % in hospitalizations ( 95 % CI , 10 % to 44 % ) , 29 % in hospital days ( 95 % CI , 8 % to 45 % ) , and 24 % in emergency department visits ( 95 % CI , 3 % to 40 % ) . CONCLUSION After adjustment , offering housing and case management to a population of homeless adults with chronic medical illnesses result ed in fewer hospital days and emergency department visits , compared with usual care . TRIAL REGISTRATION clinical trials.gov Identifier : NCT00490581 Study objective . We sought to determine socioeconomic and demographic factors that predict frequent emergency department ( ED ) use among asthmatics in Southeastern Pennsylvania . Design . Retrospective cohort study using the 2004 Philadelphia Health Management Corporation 's Southeastern Pennsylvania Household Health Survey . Setting and participants . Health behaviors were surveyed using telephone interviews ( r and om-digit dialing ) in Bucks , Montgomery , Delaware , Philadelphia , and Chester counties . Response rate was 30 % . Results . Of 13,342 respondents , 1,799 ( 13 % ) stated that they had asthma . The mean reported visits in 12 months were as follows : clinic—1.2 ( SD 2.7 ) ; doctor 's office—4.7 ( SD 5.6 ) ; ED—0.8 ; ( SD 1.8 ) ; overnight hospitalizations—0.4 ( SD 0.9 ) . Most ( 91 % ) reported that a primary care doctor was their principal source of care , whereas 2 % reported the ED as their principal source of care . Frequent ED use ( ≥3 visits/12 months ) was reported in 180 ( 10 % ) . Frequent ED use was associated with race , education , diabetes , mental illness , smoking at home , and language barriers ( p < 0.001 ) as well as indicators of severity of illness ( clinic visits , office visits , prescription for asthma medication , p < 0.001 ) . Using multivariable logistic regression , predictors of frequent ED use were : prescription for asthma meds ( OR 2.3 , 95%CI 1.4–3.7 ) , having Medicaid or Medical Assistance ( OR 1.7 , 95%CI 1.1–2.6 ) , having a high school education or less ( OR 1.5 , 95%CI 1.0–2.3 ) , number of clinic visits ( OR 1.1 , 95 % CI 1.1–1.1 ) , office visits ( OR 1.1 , 95%CI 1.1–1.1 ) , number of children living in the house ( OR 1.2 , 95 % CI 1.0–1.3 ) , and living in Philadelphia ( OR 2.0 , 95 % CI 1.3–3.1 ) . Conclusions . Frequent ED use is associated with demographic factors , geographic factors , and markers of severity of illness . While care guidelines recommend prompt referral to a primary care physician to prevent ED visits , given the level of primary care use in this population , frequent primary care attendance alone may not prevent asthma-related ED visits OBJECTIVE The objective of the study was to test the hypothesis that clinical case management is more cost-effective than usual care for frequent users of the emergency department ( ED ) . METHODS The study is a 24-month r and omized trial obtaining data on psychosocial problems through interviews and service usage and cost data from administrative records . RESULTS Two-hundred fifty-two frequent users were r and omized ( 167 to case management , 85 to usual care ) .  Case management was associated with statistically significant reductions in psychosocial problems common among ED frequent users , including homelessness , alcohol use , lack of health insurance and social security income , and financial need .  Case management was associated with statistically significant reductions in ED use and cost .  Case management and usual care patients did not differ in use or cost of other hospital services . CONCLUSIONS Case management appears cost-effective for ED frequent users because it yields statistically and clinical ly significant reductions in psychosocial problems at a cost similar to that of usual care OBJECTIVE : To describe primary care clinic use and emergency department ( ED ) use for a cohort of public hospital patients seen in the ED , identify predictors of frequent ED use , and ascertain the clinical diagnoses of those with high rates of ED use . DESIGN : Cohort observational study . SETTING : A public hospital in Atlanta , Georgia . PATIENTS : R and om sample of 351 adults initially surveyed in the ED in May 1992 and followed for 2 years . MEASUREMENTS AND MAIN RESULTS : Of the 351 patients from the initial survey , 319 ( 91 % ) had at least one ambulatory visit in the public hospital system during the following 2 years and one third of the cohort was hospitalized . The median number of subsequent ED visits was 2 ( mean 6.4 ) , while the median number of visits to a primary care appointment clinic was 0 ( mean 1.1 ) with only 90 ( 26 % ) of the patients having any primary care clinic visits . The 58 patients ( 16.6 % ) who had more than 10 subsequent ED visits accounted for 65.6 % of all subsequent ED visits . Overall , patients received 55 % of their subsequent ambulatory care in the ED , with only 7.5 % in a primary care clinic . In multivariate regression , only access to a telephone ( odd 
    Output:
    
On average , these patients have higher acuity complaints and are at greater risk for hospitalization than occasional ED users .
However , the opposite may be true of the highest-frequency ED users .
Frequent users are also heavy users of other parts of the health care system .
Only a minority of frequent ED users remain in this group long term .
Complaints vary with age , location , and usage patterns .