chronic kidney disease ( ckd ) is a major cause of morbidity and mortality in mexico .
it has been estimated that 8% of the mexican population has an estimated glomerular filtration rate ( egfr ) < 60/ml / min per 1.73  m. data from the mexican national health survey 2000 indicate that risk factors for ckd are disproportionally higher among the poor .
they present high rates of physical and mental illness , substance abuse , and early mortality .
the role of substance abuse , alcoholism , and homelessness in ckd and its risk factors has not been adequately evaluated .
additionally , homeless persons are more likely to use acute hospital - based care , less likely to be aware of their illnesses , and less likely to comply with prescribed medications and therapy .
little is known about the prevalence of ckd and its risk factors in this population . among 15,353 individuals identified with ckd stages 35 receiving regular ambulatory care in an urban community health - care network ,
an estimated 6% were homeless and 46% were unemployed , disabled , and/or receiving public assistance .
hypertension and diabetes affected 46% and 22% of individuals , respectively ; the prevalence of alcoholism ( 8% ) , depression ( 16% ) , drug abuse ( 16% ) , and chronic viral diseases such as hcv ( 4% ) and hiv ( 3% ) were also notable . since 1998 ,
the fundacion hospitales civiles de guadalajara has used mobile units to provide health care for the poor in jalisco , with emphasis on disease prevention and early detection . in partnership with the jalisco institute for social welfare ( ijas ) , a state welfare agency , we screened homeless individuals in urban guadalajara for the presence of ckd and its risk factors .
since september 2006 , staff from the hospitales civiles de guadalajara have used mobile units to establish temporary ckd screening stations in poor rural and urban communities in jalisco . in the present report participants
were located at ijas ' unit of assistance for the homeless and three other locations in the jalisco state capital , guadalajara .
the mobile unit included facilities for history taking , physical examination , phlebotomy , and laboratory equipment to perform on - site laboratory measurements .
it was staffed by personnel that included one nurse , one social worker , one physician , and one laboratory technician , with the support of individuals receiving training in community medicine ( nursing or medical students and medical residents ) .
briefly , data were collected prospectively by the staff of the screening programs using a standardized form .
persons who were aware that they had  kidney disease ' were not screened ; all others were eligible to participate .
participants provided blood specimens used to measure serum creatinine and total cholesterol ; serum triglycerides and glucose were measured in those who had been fasting for at least 8  h before specimen collection .
participants also provided urine specimens for dipstick urinalysis . trained experienced personnel working in well - lit and appropriate working conditions interpreted the results of urinalyses , which were considered to indicate proteinuria if they showed 1 + protein .
participants were classified as having diabetes mellitus if they gave a history of diabetes , or had fasting blood glucose > 126  mg / dl .
serum creatinine was used to determine the egfr using the modification of diet in renal diseases study equation ; participants were classified as having ckd based on the presence or absence of egfr < 60  ml / min per 1.73  m. participants ' body mass index was classified according to the current who scheme .
homeless was defined as a person who has no income of his or her own to satisfy basic needs , and who does not have a place to live .
alcohol and tobacco consumption , as well as substance abuse , was defined as their use at any time during the previous 12 months .
findings were compared with those reported by the mexican national health survey and nutrition ( mnhsn ) 2006 and by the mexican national survey on addictions ( mnsa ) 2002 for the general population , and with our own reported data on ckd in poor communities in jalisco , mexico .
t - tests and chi - squared tests ( as appropriate ) were used to perform comparisons between groups .
the institutional review boards of the hospital civil de guadalajara and the university of alberta approved this study .
260 homeless individuals were screened ; they were predominantly male ( 74% vs. 49.7% vs. 29% , p=0.0001 ) when compared to the general mexican and poor jalisco populations , respectively .
they were younger ( 50.7517.93 vs. 57.413.0 years , p=0.0001 ) than the high - risk population .
only 5.8% of homeless patients knew they had diabetes , but 19% had fasting blood sugar > 126  mg / dl ; 3.5% of homeless patients knew they were hypertensive but 31% had systolic blood pressure 140  mm  hg or diastolic blood pressure 90  mm  hg , similar to the general population but lower than the poor jalisco population ( 31.0% vs. 62% , p=0.0001 ) .
the prevalence of obesity among homeless participants was lower than in the general and poor jalisco populations ( 17.6% vs. 31% and 43% , respectively , p=0.0001 ) .
ckd , as defined by egfr<60  ml / min per 1.73  m , was more prevalent among the homeless than in the poor jalisco population ( 22.4% vs. 15.8% , p=0.0001 ) ; 16.5% had stage 3 , 4.3% stage 4 , and 1.2% stage 5 ckd .
homeless individuals with ckd were older ( 60.7914.86 vs. 47.5717.62 years , p=0001 ) and more diabetic ( 18.1 vs. 16.2 , p=0.03 ) than those without ckd .
obesity ( 23.4% vs. 16.0% , p=0.27 ) and hypertension ( 34.5% vs. 30.3% , p=0.62 ) were more prevalent in persons with ckd , but these differences were not statistically significant .
unfortunately , results of urinalysis are not reported because the majority ( 95% ) of individuals refused to submit a urine sample , arguing the risk of being tested for drugs .
addictions were more prevalent among the homeless than in the general population ( 75.3% vs. 55.1% , p=0.0001 ) ( table 2 ) .
homeless persons showed a lower prevalence of alcoholism ( 23.5% vs. 32.3% , p=0.002 ) than the general population , but tobacco smoking ( 34.6% vs. 21.5% , p=0.0001 ) and substance abuse ( 18% vs. 1.1% , p=0.0001 ) were more prevalent among the homeless . likewise , chronic viral infections such as hiv ( 4.5% vs. 0.3% , p=0.0001 ) and hcv ( 7.7% vs. 1.4% , p=0.0001 ) were also significantly higher among the homeless than in the general population .
it is estimated that 8% of the adult mexican population has egfr < 60  ml / min per 1.73 m ( ref . ) and that the prevalence is as high as 15.8% among high - risk , poor populations .
risk factors for ckd such as diabetes , hypertension , and obesity are highly prevalent in the mexican population .
our results show a higher prevalence of ckd ( 22% ) among the homeless compared with the report by amato et al ( 8% ) , and our own data in poor urban and rural jalisco populations ( 15.8% ) .
since the prevalence of traditional ckd risk factors like diabetes and hypertension among the homeless was lower than among the urban and rural poor populations , additional factors could explain this difference .
first , the higher prevalence of chronic viral infections and substance abuse among the homeless could have played a role in the development of chronic glomerular disease ; however , the lack of urine samples to test for protein and sediment did not allow us to assess this possibility .
second , as homeless individuals have limited access to health care , the presence of ckd risk factors may go unnoticed , increasing the risk of developing ckd .
also , homeless persons are less likely to be aware of their illnesses , and to comply with prescribed medications and therapy . as shown in our study , the majority of people with documented diabetes and hypertension were unaware of these conditions , and none had health insurance
. finally , homeless patients are more likely to present late in the course of ckd , which might lead to more rapid loss of kidney function .
as shown in our study , 14 ( 5.5% ) of the screened individuals had ckd stages 4 and 5 and had not ever seen a nephrologist .
although data were collected prospectively , they may not be generalizable to all homeless settings in other regions of mexico .
second , participants who agreed to participate in screening delivered by the mobile clinic may not be representative of those who would participate in other types of screening programs .
therefore , our results can not be used to draw conclusions about the overall prevalence of ckd in homeless individuals in mexico .
third , although the refusal to provide urine samples did not allow us to test for protein and hematuria , our results suggest that screening using mobile units in the population studied leads to a relatively high detection rate for reduced egfr .
fourth , the mdrd study equation has not been validated specifically in an unselected mexican population ; therefore , some participants may have been misclassified with respect to the presence or absence of egfr 60  ml / min per 1.73  m. finally , there is no information on the number of homeless people in mexico . in guadalajara , jalisco 's state capital ,
, the state government has been providing shelter and medical care to this population through the ijas 's unit of assistance to the homeless .
our results indicate that more efforts need to be directed to assess the burden of ckd in this setting . in summary , ckd and its risk factors
lack of awareness of having diabetes and hypertension is highly common in this population , as is the prevalence of chronic viral infections and substance abuse .
consideration should be given to target this high - risk population in programs aimed to prevent ckd and its risk factors in mexico .
 little is known about the prevalence of chronic kidney disease ( ckd ) among the homeless in mexico . 
 the role of substance abuse , alcoholism , and homelessness in ckd has not been properly evaluated . 
 we screened 260 homeless individuals in the state of jalisco , mexico , for the presence of ckd and its risk factors , and compared their characteristics with those from a separate cohort of poor jalisco residents and with a survey of the general mexican population . 
 ckd was more prevalent among the homeless than among the poor jalisco population ( 22% vs. 15.8% , p=0.0001 ) ; 16.5% had stage 3 , 4.3% stage 4 , and 1.2% stage 5 . 
 all were unaware of having ckd . 
 only 5.8% knew they had diabetes , but 19% had fasting blood sugar > 126  mg / dl ; 3.5% knew they were hypertensive but 31% had systolic blood pressure 140  mm  hg or diastolic blood pressure 90  mm  hg . 
 alcoholism was less common than in the poor jalisco population ( 23.5% vs. 32.3% , p=0.002 ) , but tobacco smoking ( 34.6% vs. 21.5% , p=0.0001 ) and substance abuse ( 18% vs. 1.1% , p=0.0001 ) were more prevalent among the homeless . 
 likewise , chronic viral infections such as hiv ( 4.5% vs. 0.3% , p=0.0001 ) and hcv ( 7.7% vs. 1.4% , p=0.0001 ) were also significantly higher among the homeless than in the general population . in conclusion , ckd and its risk factors are highly prevalent among the homeless individuals in jalisco , mexico . 
 lack of awareness of having diabetes and hypertension is highly common , as is substance abuse . 
 programs aiming to prevent ckd and its risk factors in mexico should specifically target this high - risk population . 
INTRODUCTION
METHODS
RESULTS
DISCUSSION