***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: Death rates of end-stage renal disease ( ESRD ) patients treated with hemodialysis vary substantially among treatment centers . The association between facility-to-facility differences in delivered hemodialysis dose and facility-specific mortality rates was examined among 5817 r and omly selected patients treated with hemodialysis on October 1 , 1994 , from all 213 hemodialysis treatment centers reporting to ESRD Network 6 . The mean urea reduction ratio ( URR ) for each treatment center , a measure of hemodialysis adequacy , was calculated for each facility , using measurements made by center staff members during one treatment for each of the r and omly selected patients . During 7 mo of follow-up ( ending April 30 , 1995 ) , 441 ( 7.6 % ) patients died . The average URR among the treatment centers was 64.9 % . There was a strong , inverse association between increasing treatment center URR and adjusted mortality count ( P = 0.009 ) . Other treatment center characteristics associated with increased mortality included free-st and ing status ( P = 0.009 ) and decreasing frequency of reported physician supervision of care ( P = 0.01 ) . It was concluded that lower average levels of dialysis adequacy in treatment centers are associated with higher rates of death , and this association persists after controlling for facility-to-facility differences in patient and nonpatient characteristics This historic prospect i ve study assessed the relationship between dialyzer reuse practice s and hemodialysis patient mortality through 1 year of follow-up . Medicare patient demographic and survival data were combined with dialyzer reuse data from the Centers for Disease Control and Prevention 's annual survey of dialysis-related diseases . Data were analyzed for the US Medicare hemodialysis population of never transplanted patients prevalent on January 1 , 1989 , and January 1 , 1990 , who were treated in freest and ing dialysis units that used primarily conventional ( not high-flux ) dialyzers .  Time to mortality , or transplant , and other censoring on December 31st of each year was regressed with proportional hazards models on patient , dialysis unit , and reuse measures . Age- , race- , and diagnosis-st and ardized mortality ratios for dialysis units were also regressed with weighted least squares techniques against dialysis unit and reuse measures . The results showed that patients treated in dialysis units that disinfected dialyzers with a peracetic acid , hydrogen peroxide , acetic acid mixture , or glutaraldehyde experienced higher mortality than patients treated in units that used formalin or in units that did not reuse dialyzers . The relative risk of mortality , compared with patients treated in nonreuse dialysis units , was 1.17 ( P = 0.010 ) for glutaraldehyde and 1.13 ( P < 0.001 ) for the peracetic acid mixture . The relative risk for formalin compared with the reference group of nonreuse was 1.06 ( P = 0.088 ) . With adjustment for several patient and dialysis unit characteristics , dialyzer reuse with certain germicides was associated with a significantly elevated mortality risk . This elevated risk , the etiology of which is currently not known , may represent a large number of potentially avoidable deaths per year . Only a large , nationally based analysis of this type has sufficient sample size to detect mortality risks such as these We analyzed the effect of patient and  dialysis unit characteristics on access to  kidney transplantation  using several different approaches , including an analysis of individual patient data from a systematic r and om sample of 2900 new dialysis patients from each year 1981 to 1985 ( 14721 patients total ) . Additional analyses focused on the composition of transplant waiting lists and aggregate data from a 1984 census of 1133 dialysis and transplant units . White , male , young , nondiabetic , high-income patients treated in smaller units are more likely to receive a cadaver transplant under Medicare than are other kidney patients . Profit status of the dialysis unit was not found to be correlated to access to transplantation , although size of the unit may be correlated to access . Future analysis should focus on whether patient access has been inappropriately compromised . Possible factors unexplored in this analysis include differential patient preferences and medical suitability , as well as differential medical access The diverse patient and dialysis unit characteristics in the United States pose challenges for assessing the safety and efficacy of reuse practice s. A 10 % r and om sample of period-prevalent hemodialysis patients from units practicing conventional dialysis ( < 25 % of patients with high-efficiency/high-flux dialysis )  were analyzed . The data included 13,926 patient observations in 1989 - 1990 and 20,422 in 1991 - 1993 . Centers for Disease Control and Prevention and Health Care Financing Administration facility survey Medicare data were analyzed with a Cox regression model , evaluating the risk of reuse compared with no reuse and adjusting for comorbidity , unit characteristics , and profit status . In 1989 - 1990 , freest and ing and hospital-based units that did not reuse dialyzers were not significantly different from each other in mortality rates . In 1991 - 1993 , however , no-reuse , freest and ing , for-profit units had higher risks ( relative risk [ RR ] = 1.23 , P = 0.003 ) compared with no-reuse , hospital-based , nonprofit units . No-reuse , hospital-based , for-profit units , in contrast , were associated with a lower mortality risk ( RR = 0.70 , P = 0.0001 ) . An isolated higher risk associated with peracetic acid manual reuse in freest and ing units ( 1989 - 1990 ) was identified in for-profit units only . In the 1991 - 1993 period , an increased mortality risk was noted in hospital-based , nonprofit units practicing formaldehyde automatic reuse , and in freest and ing , for-profit units using glutaraldehyde , which accounted for < 5 % of all units . All other interactions of reuse germicide and technique were not different from no-reuse . The varying mortality rates identified in both no-reuse and reuse units using conventional dialysis suggest that other factors , such as dialysis therapy and anemia correction ( both known predictors of patient survival ) , have a greater influence on U.S. mortality than reuse germicides and techniques Decrease in the average duration of hemodialysis treatment time is a continuing phenomenon . We investigated the relationship of 3-year mortality to duration of dialysis in a 1984 - 1985 national r and om sample of 600 hemodialysis patients from 36 dialysis units .  Mortality was negatively associated with duration of dialysis treatments , as shown by the Cox model , adjusted for other patient and dialysis unit covariates . With adjustment for other covariates , patients receiving an average dialysis treatment duration of less than 3.5 hours had relative mortality risks of 1.17 to 2.18 compared with those with treatments longer than 3.5 hours ( mortality risk of 1.0 ) . Reverse causation ( the possibility that more seriously ill patients received dialysis for a shorter time ) appears unlikely . We conclude that duration of the dialysis procedure is an important element in determining patient mortality as one of the factors determining the adequacy of dialysis 
    Output:
    
Hemodialysis care in private not-for-profit centers is associated with a lower risk of mortality compared with care in private for-profit centers