PMCC PMCC

Search tips
Search criteria

Advanced
Results 1-25 (26)
 

Clipboard (0)
None

Select a Filter Below

Year of Publication
2.  An Aboriginal Australian Genome Reveals Separate Human Dispersals into Asia 
Science (New York, N.Y.)  2011;334(6052):94-98.
We present an Aboriginal Australian genomic sequence obtained from a 100-year-old lock of hair donated by an Aboriginal man from southern Western Australia in the early 20th century. We detect no evidence of European admixture and estimate contamination levels to be below 0.5%. We show that Aboriginal Australians are descendants of an early human dispersal into eastern Asia, possibly 62,000 to 75,000 years ago. This dispersal is separate from the one that gave rise to modern Asians 25,000 to 38,000 years ago. We also find evidence of gene flow between populations of the two dispersal waves prior to the divergence of Native Americans from modern Asian ancestors. Our findings support the hypothesis that present-day Aboriginal Australians descend from the earliest humans to occupy Australia, likely representing one of the oldest continuous populations outside Africa.
doi:10.1126/science.1211177
PMCID: PMC3991479  PMID: 21940856
3.  Agreement of reported vascular access on the medical evidence report and on medicare claims at hemodialysis initiation 
BMC Nephrology  2014;15:30.
Background
The choice of vascular access type is an important aspect of care for incident hemodialysis patients. However, data from the Centers for Medicare & Medicaid Services (CMS) Medical Evidence Report (form CMS-2728) identifying the first access for incident patients have not previously been validated. Medicare began requiring that vascular access type be reported on claims in July 2010. We aimed to determine the agreement between the reported vascular access at initiation from form CMS-2728 and from Medicare claims.
Methods
This retrospective study used a cohort of 9777 patients who initiated dialysis in the latter half of 2010 and were eligible for Medicare at the start of renal replacement therapy to compare the vascular access type reported on form CMS-2728 with the type reported on Medicare outpatient dialysis claims for the same patients. For each patient, the reported access from each data source was compiled; the percent agreement represented the percent of patients for whom the access was the same. Multivariate logistic analysis was performed to identify characteristics associated with the agreement of reported access.
Results
The two data sources agreed for 94% of patients, with a Kappa statistic of 0.83, indicating an excellent level of agreement. Further, we found no evidence to suggest that agreement was associated with the patient characteristics of age, sex, race, or primary cause of renal failure.
Conclusion
These results suggest that vascular access data as reported on form CMS-2728 are valid and reliable for use in research studies.
doi:10.1186/1471-2369-15-30
PMCID: PMC3922277  PMID: 24507475
Hemodialysis; Medicare; Validation; Vascular access
4.  High Selection Pressure Promotes Increase in Cumulative Adaptive Culture 
PLoS ONE  2014;9(1):e86406.
The evolution of cumulative adaptive culture has received widespread interest in recent years, especially the factors promoting its occurrence. Current evolutionary models suggest that an increase in population size may lead to an increase in cultural complexity via a higher rate of cultural transmission and innovation. However, relatively little attention has been paid to the role of natural selection in the evolution of cultural complexity. Here we use an agent-based simulation model to demonstrate that high selection pressure in the form of resource pressure promotes the accumulation of adaptive culture in spite of small population sizes and high innovation costs. We argue that the interaction of demography and selection is important, and that neither can be considered in isolation. We predict that an increase in cultural complexity is most likely to occur under conditions of population pressure relative to resource availability. Our model may help to explain why culture change can occur without major environmental change. We suggest that understanding the interaction between shifting selective pressures and demography is essential for explaining the evolution of cultural complexity.
doi:10.1371/journal.pone.0086406
PMCID: PMC3906051  PMID: 24489724
7.  Determination of dosage compensation of the mammalian X chromosome by RNA-seq is dependent on analytical approach 
BMC Genomics  2013;14:150.
Background
An enduring question surrounding sex chromosome evolution is whether effective hemizygosity in the heterogametic sex leads inevitably to dosage compensation of sex-linked genes, and whether this compensation has been observed in a variety of organisms. Incongruence in the conclusions reached in some recent reports has been attributed to different high-throughput approaches to transcriptome analysis. However, recent reports each utilizing RNA-seq to gauge X-linked gene expression relative to autosomal gene expression also arrived at diametrically opposed conclusions regarding X chromosome dosage compensation in mammals.
Results
Here we analyze RNA-seq data from X-monosomic female human and mouse tissues, which are uncomplicated by genes that escape X-inactivation, as well as published RNA-seq data to describe relative X expression (RXE). We find that the determination of RXE is highly dependent upon a variety of computational, statistical and biological assumptions underlying RNA-seq analysis. Parameters implemented in short-read mapping programs, choice of reference genome annotation, expression data distribution, tissue source for RNA and RNA-seq library construction method have profound effects on comparing expression levels across chromosomes.
Conclusions
Our analysis shows that the high number of paralogous gene families on the mammalian X chromosome relative to autosomes contributes to the ambiguity in RXE calculations, RNA-seq analysis that takes into account that single- and multi-copy genes are compensated differently supports the conclusion that, in many somatic tissues, the mammalian X is up-regulated compared to the autosomes.
doi:10.1186/1471-2164-14-150
PMCID: PMC3769146  PMID: 23497106
RNA-seq; X chromosome; Dosage compensation
8.  Long-Term Consequences of Kidney Donation 
The New England journal of medicine  2009;360(5):459-469.
BACKGROUND
The long-term renal consequences of kidney donation by a living donor are attracting increased appropriate interest. The overall evidence suggests that living kidney donors have survival similar to that of nondonors and that their risk of end-stage renal disease (ESRD) is not increased. Previous studies have included relatively small numbers of donors and a brief follow-up period.
METHODS
We ascertained the vital status and lifetime risk of ESRD in 3698 kidney donors who donated kidneys during the period from 1963 through 2007; from 2003 through 2007, we also measured the glomerular filtration rate (GFR) and urinary albumin excretion and assessed the prevalence of hypertension, general health status, and quality of life in 255 donors.
RESULTS
The survival of kidney donors was similar to that of controls who were matched for age, sex, and race or ethnic group. ESRD developed in 11 donors, a rate of 180 cases per million persons per year, as compared with a rate of 268 per million per year in the general population. At a mean (±SD) of 12.2±9.2 years after donation, 85.5% of the subgroup of 255 donors had a GFR of 60 ml per minute per 1.73 m2 of body-surface area or higher, 32.1% had hypertension, and 12.7% had albuminuria. Older age and higher body-mass index, but not a longer time since donation, were associated with both a GFR that was lower than 60 ml per minute per 1.73 m2 and hypertension. A longer time since donation, however, was independently associated with albuminuria. Most donors had quality-of-life scores that were better than population norms, and the prevalence of coexisting conditions was similar to that among controls from the National Health and Nutrition Examination Survey (NHANES) who were matched for age, sex, race or ethnic group, and body-mass index.
CONCLUSIONS
Survival and the risk of ESRD in carefully screened kidney donors appear to be similar to those in the general population. Most donors who were studied had a preserved GFR, normal albumin excretion, and an excellent quality of life.
doi:10.1056/NEJMoa0804883
PMCID: PMC3559132  PMID: 19179315
9.  Kidney function and risk triage in adults: threshold values and hierarchical importance 
Kidney international  2010;79(1):99-111.
In this study, we attempted to identify threshold values for kidney function measures that maximally discriminate short-term mortality, to identify major population segments in which these thresholds apply, and to classify the hierarchical rank of the thresholds when other classic risk factors are also considered. To do this we retrospectively identified estimated glomerular filtration rate (eGFR) and urinary albumin–creatinine ratio (ACR) thresholds to maximize sensitivity and specificity predictions for death in non-institutionalized NHANES III participants, representative of the United States population from 1988 to 1994 and followed through 2000. In a classification tree excluding dichotomizing variables, age 57 years was initially selected; ACR appeared in the second round and eGFR in the third. The prognostic discrimination of optimum eGFR and ACR thresholds exceeded those of commonly advocated public health screening measures, such as LDL cholesterol and fasting blood glucose, with body mass index appearing in the third round, and smoking and LDL cholesterol in the fourth. In a tree permitting dichotomizing variables, the ACR, systolic blood pressure, and glucose first appeared in the third round, with eGFR, smoking, and LDL in the fourth. Thus, the albumin–creatinine ratio and eGFR may be at least as efficient for survival-based clinical triage as most other classic risk factors.
doi:10.1038/ki.2010.291
PMCID: PMC3513940  PMID: 20720528
albumin–creatinine ratio; estimated glomerular filtration rate; mortality; survival
10.  Cystatin C, mortality risk and clinical triage in US adults: threshold values and hierarchical importance 
Nephrology Dialysis Transplantation  2010;26(6):1831-1837.
Background. It has been suggested that cystatin C may be a superior measure of estimated glomerular filtration rate (eGFR) than creatinine-based methods. We aimed to assess the utility of cystatin C for clinical triage in community-based settings.
Methods. We identified cystatin C thresholds that maximize sensitivity and specificity (MaxSn + Sp) for predicting death and subsequently applied classification tree methodology considering serum creatinine, creatinine-based eGFR, urinary albumin–creatinine ratio and conventional modifiable risk factors to define subgroups, interactions and hierarchical ranks in fasting US adults (National Health and Nutrition Examination Survey 1988–94, followed through 2006).
Results. A threshold cystatin C value of 0.94 mg/L exhibited the best maximum combined value of sensitivity and specificity for predicting death (MaxSn + Sp, Sn 0.64/Sp 0.78). When all variables were considered jointly in a classification tree, cystatin C and albumin–creatinine ratio were the primary mortality discriminators in subgroups that added up to 41 and 14% of the study population, respectively; serum creatinine and creatinine-based eGFR were non-discriminatory.
Conclusion. Cystatin C may be useful for risk-based clinical triage in public health settings.
doi:10.1093/ndt/gfq629
PMCID: PMC3145398  PMID: 20961890
albumin–creatinine ratio; creatinine; cystatin C; estimated glomerular filtration rate; mortality
11.  Cognitive Impairment in Peritoneal Dialysis Patients 
Background
Prevalence of moderate to severe cognitive impairment among hemodialysis patients is more than double the prevalence in the general population. This study describes cognitive impairment occurrence in a peritoneal dialysis cohort compared with a cohort without chronic kidney disease (CKD).
Study Design
Cross-sectional study.
Setting and Participants
51 English-speaking peritoneal dialysis patients from two urban dialysis units, compared with 338 hemodialysis patients from 16 urban dialysis units and 101voluntary controls without CKD from urban general medicine clinics.
Predictor
A 45-minute battery of nine validated neuropsychological tests (cognitive domains memory, executive function, language).
Outcomes
Mild, moderate, or severe cognitive impairment, classified according to a previously designed algorithm.
Results
Of the peritoneal dialysis cohort, 33.3% had no or mild, 35.3% moderate, and 31.4% severe cognitive impairment; corresponding values were 60.4%, 26.7%, and 12.9% of the non-CKD cohort, and 26.6%, 36.4%, and 37.0% of the hemodialysis cohort. A logistic regression model including age, sex, race, education, hemoglobin, diabetes, and stroke showed that only non-white race (P = 0.002) and education (P = 0.002) were associated with moderate to severe cognitive impairment in the peritoneal dialysis cohort. Compared with hemodialysis patients, more peritoneal dialysis patients had moderate to severe memory impairment (60% vs. 52%), but fewer had impaired executive function (one-third vs. one-half). Peritoneal dialysis was associated with a more than 2.5-fold increased risk of moderate to severe cognitive impairment compared with no CKD (OR, 2.58; 95% confidence interval 1.02-6.53), as was hemodialysis (OR, 3.16; 95% CI, 1.91-5.24), in an adjusted logistic regression model.
Limitations
Small sample size, participation rate somewhat low.
Conclusions
Similar to hemodialysis patients, two-thirds of peritoneal dialysis patients had moderate to severe cognitive impairment, enough to interfere with safely self-administering dialysis and adhering to complex medication regimens. These patients could benefit from cognitive assessment before and periodically after dialysis initiation.
doi:10.1053/j.ajkd.2010.11.026
PMCID: PMC3121243  PMID: 21295896
12.  A Maternal Influence on Reading the Mind in the Eyes Mediated by Executive Function: Differential Parental Influences on Full and Half-Siblings 
PLoS ONE  2011;6(8):e23236.
Background
Parent-of-origin effects have been found to influence the mammalian brain and cognition and have been specifically implicated in the development of human social cognition and theory of mind. The experimental design in this study was developed to detect parent-of-origin effects on theory of mind, as measured by the ‘Reading the mind in the eyes’ (Eyes) task. Eyes scores were also entered into a principal components analysis with measures of empathy, social skills and executive function, in order to determine what aspect of theory of mind Eyes is measuring.
Methodology/Principal Findings
Maternal and paternal influences on Eyes scores were compared using correlations between pairs of full (70 pairs), maternal (25 pairs) and paternal siblings (15 pairs). Structural equation modelling supported a maternal influence on Eyes scores over the normal range but not low-scoring outliers, and also a sex-specific influence on males acting to decrease male Eyes scores. It was not possible to differentiate between genetic and environmental influences in this particular sample because maternal siblings tended to be raised together while paternal siblings were raised apart. The principal components analysis found Eyes was associated with measures of executive function, principally behavioural inhibition and attention, rather than empathy or social skills.
Conclusions/Significance
In conclusion, the results suggest a maternal influence on Eye scores in the normal range and a sex-specific influence acting to reduce scores in males. This influence may act via aspects of executive function such as behavioural inhibition and attention. There may be different influences acting to produce the lowest Eyes scores which implies that the heratibility and/or maternal influence on poor theory of mind skills may be qualitatively different to the influence on the normal range.
doi:10.1371/journal.pone.0023236
PMCID: PMC3151289  PMID: 21850264
13.  Treatment of anemia in chronic kidney disease: known, unknown, and both 
Journal of blood medicine  2011;2:103-112.
Erythropoiesis is a rapidly evolving research arena and several mechanistic insights show therapeutic promise. In contrast with the rapid advance of mechanistic science, optimal management of anemia in patients with chronic kidney disease remains a difficult and polarizing issue. Although several large hemoglobin target trials have been performed, optimal treatment targets remain elusive, because none of the large trials to date have unequivocally identified differences in primary outcome rates or death rates, and because other reported outcomes indicate the potential for harm (rates of stroke, early requirement for dialysis, and vascular access thrombosis) and benefit (reductions in transfusion requirements and fatigue).
doi:10.2147/JBM.S13066
PMCID: PMC3262350  PMID: 22287869
hemoglobin; erythropoietin; oxygen-sensing; target trial; methodology
14.  Stirring up the Mud: Using a Community-Based Participatory Approach to Address Health Disparities through a Faith-Based Initiative 
This case study provides a mid-course assessment of the Bronx Health REACH faith-based initiative four years into its implementation. The study uses qualitative methods to identify lessons learned and to reflect on the benefits and challenges of using a community-based participatory approach for the development and evaluation of a faith-based program designed to address health disparities. Key findings concern the role of pastoral leadership, the importance of providing a religious context for health promotion and health equality messages, the challenges of creating a bilingual/bi-cultural program, and the need to provide management support to the lay program coordinators. The study also identifies lessons learned about community-based evaluation and the importance of addressing community concern about the balance between evaluation and program. Finally, the study identifies the challenges that lie ahead, including issues of program institution-alization and sustainability.
doi:10.1353/hpu.0.0221
PMCID: PMC3065238  PMID: 20168022
Health disparities; race/ethnicity; community-based participatory research; faith-based initiatives
16.  The ecology of social transitions in human evolution 
We know that there are fundamental differences between humans and living apes, and also between living humans and their extinct relatives. It is also probably the case that the most significant and divergent of these differences relate to our social behaviour and its underlying cognition, as much as to fundamental differences in physiology, biochemistry or anatomy. In this paper, we first attempt to demarcate what are the principal differences between human and other societies in terms of social structure, organization and relationships, so that we can identify what derived features require explanation. We then consider the evidence of the archaeological and fossil record, to determine the most probable context in time and taxonomy, of these evolutionary trends. Finally, we attempt to link five major transitional points in hominin evolution to the selective context in which they occurred, and to use the principles of behavioural ecology to understand their ecological basis. Critical changes in human social organization relate to the development of a larger scale of fission and fusion; the development of a greater degree of nested substructures within the human community; and the development of intercommunity networks. The underlying model that we develop is that the evolution of ‘human society’ is underpinned by ecological factors, but these are influenced as much by technological and behavioural innovations as external environmental change.
doi:10.1098/rstb.2009.0136
PMCID: PMC2781881  PMID: 19805433
human evolution; social structure; social evolution; hominin behaviour; technological evolution
17.  Prevalence of CKD in the United States: A Sensitivity Analysis Using the National Health and Nutrition Examination Survey (NHANES) 1999–2004 
Background
Estimates of chronic kidney disease (CKD) in the United States, using the continuous National Health and Nutrition Examination Survey (NHANES) dataset 1999–2004, indicate that 13.1% of the population (26.3 million people based on the 2000 census) has CKD stages 1–4.
Study Design
We performed sensitivity analyses to highlight assumptions underlying these estimates and to illustrate their robustness to varying assumptions.
Setting & Participants
NHANES 1999–2004 was a nationally representative cross-sectional continuous survey of the civilian, non-institutionalized US population. Our sample included participants aged ≥ 20 years.
Reference Test
Estimated glomerular filtration rate (GFR) < 60 mL/min/1.73m2 defined from the 4-variable Modification of Diet in Renal Disease (MDRD) Study equation; albuminuria defined as persistence of urinary albumin-to-creatinine ratio > 30 mg/g.
Index Tests
[EF1]. We compared the prevalence estimates using the MDRD Study equation with 2 other GFR estimating equations (equation #5 by Rule and colleagues from the Mayo Clinic Donors study; Cockcroft-Gault equation adjusted for body surface area and corrected for the bias in the MDRD Study sample), and sex-specific cut points to define albuminuria.
Results
We found CKD stages 1–4 prevalence estimates ranging from 11.7% to 24.9%, a more than 2-fold difference, resulting in population estimates between 25.8 million and 54.0 million people using 2006 population estimates. Considering only stages 3 and 4, which are not affected by the choice of cut points to define albuminuria, prevalence estimates ranged from 6.3% to 18.6%, resulting in population estimates of 13.7 million to 40.3 million people, a nearly 3-fold difference.
Limitations
NHANES 1999–2004 is a cross-sectional survey, and allows for GFR and albumin-creatinine ratio estimates at one point in time. NHANES does not account for seniors in long-term care facilities.
Conclusions
While CKD prevalence is high regardless of varying modeling assumptions, different assumptions yield large differences in prevalence estimates.
doi:10.1053/j.ajkd.2008.07.034
PMCID: PMC2664624  PMID: 18950914
Index key words: Chronic kidney disease; GFR estimating equations; NHANES; prevalence estimates
18.  Associations of anemia persistency with medical expenditures in Medicare ESRD patients on dialysis 
Most end-stage renal disease (ESRD) patients begin renal replacement therapy with hemoglobin levels below the recommended US National Kidney Foundation Dialysis Outcomes Quality Initiative Guidelines lower level of 110 g/L. Although most patients eventually reach this target, the time required varies substantially. This study aimed to determine whether length of time with below-target hemoglobin levels after dialysis initiation is associated with medical costs, and if so, whether intermediate factors underlie the associations. US patients initiating dialysis in 2002 were studied using the Centers for Medicare and Medicaid Services ESRD database. Anemia persistence (time in months with hemoglobin below 110 g/L) was determined in a six-month entry period, and outcomes were assessed in the subsequent six-month follow-up period. The structural equation modeling technique was used to evaluate associations between persistent anemia and medical costs and to determine intermediate factors for these associations. The study included 28,985 patients. Mean per-patient-per-month medical cost was $6267 (standard deviation $5713) in the six-month follow-up period. Each additional month with hemoglobin below 110 g/L was associated with an 8.9% increment in medical cost. The increased cost was associated with increased erythropoietin use and blood transfusions, and increased rates of hospitalization and vascular access procedures in the follow-up period.
PMCID: PMC2690975  PMID: 19753126
anemia persistency; end-stage renal disease; medical costs; structural equation modeling
20.  Phylogeography of mtDNA haplogroup R7 in the Indian peninsula 
Background
Human genetic diversity observed in Indian subcontinent is second only to that of Africa. This implies an early settlement and demographic growth soon after the first 'Out-of-Africa' dispersal of anatomically modern humans in Late Pleistocene. In contrast to this perspective, linguistic diversity in India has been thought to derive from more recent population movements and episodes of contact. With the exception of Dravidian, which origin and relatedness to other language phyla is obscure, all the language families in India can be linked to language families spoken in different regions of Eurasia. Mitochondrial DNA and Y chromosome evidence has supported largely local evolution of the genetic lineages of the majority of Dravidian and Indo-European speaking populations, but there is no consensus yet on the question of whether the Munda (Austro-Asiatic) speaking populations originated in India or derive from a relatively recent migration from further East.
Results
Here, we report the analysis of 35 novel complete mtDNA sequences from India which refine the structure of Indian-specific varieties of haplogroup R. Detailed analysis of haplogroup R7, coupled with a survey of ~12,000 mtDNAs from caste and tribal groups over the entire Indian subcontinent, reveals that one of its more recently derived branches (R7a1), is particularly frequent among Munda-speaking tribal groups. This branch is nested within diverse R7 lineages found among Dravidian and Indo-European speakers of India. We have inferred from this that a subset of Munda-speaking groups have acquired R7 relatively recently. Furthermore, we find that the distribution of R7a1 within the Munda-speakers is largely restricted to one of the sub-branches (Kherwari) of northern Munda languages. This evidence does not support the hypothesis that the Austro-Asiatic speakers are the primary source of the R7 variation. Statistical analyses suggest a significant correlation between genetic variation and geography, rather than between genes and languages.
Conclusion
Our high-resolution phylogeographic study, involving diverse linguistic groups in India, suggests that the high frequency of mtDNA haplogroup R7 among Munda speaking populations of India can be explained best by gene flow from linguistically different populations of Indian subcontinent. The conclusion is based on the observation that among Indo-Europeans, and particularly in Dravidians, the haplogroup is, despite its lower frequency, phylogenetically more divergent, while among the Munda speakers only one sub-clade of R7, i.e. R7a1, can be observed. It is noteworthy that though R7 is autochthonous to India, and arises from the root of hg R, its distribution and phylogeography in India is not uniform. This suggests the more ancient establishment of an autochthonous matrilineal genetic structure, and that isolation in the Pleistocene, lineage loss through drift, and endogamy of prehistoric and historic groups have greatly inhibited genetic homogenization and geographical uniformity.
doi:10.1186/1471-2148-8-227
PMCID: PMC2529308  PMID: 18680585
21.  Comparative mortality of hemodialysis patients at for-profit and not-for-profit dialysis facilities in the United States, 1998 to 2003: A retrospective analysis 
BMC Nephrology  2008;9:6.
Background
Concern lingers that dialysis therapy at for-profit (versus not-for-profit) hemodialysis facilities in the United States may be associated with higher mortality, even though 4 of every 5 contemporary dialysis patients receive therapy in such a setting.
Methods
Our primary objective was to compare the mortality hazards of patients initiating hemodialysis at for-profit and not-for-profit centers in the United States between 1998 and 2003. For-profit status of dialysis facilities was determined after subjects received 6 months of dialysis therapy, and mean follow-up was 1.7 years.
Results
Of the study population (N = 205,076), 79.9% were dialyzed in for-profit facilities after 6 months of dialysis therapy. Dialysis at for-profit facilities was associated with higher urea reduction ratios, hemoglobin levels (including levels above 12 and 13 g/dL [120 and 130 g/L]), epoetin doses, and use of intravenous iron, and less use of blood transfusions and lower proportions of patients on the transplant waiting-list (P < 0.05). Patients dialyzed at for-profit and at not-for-profit facilities had similar mortality risks (adjusted hazards ratio 1.02, 95% CI 0.99–1.06, P = 0.143).
Conclusion
While hemodialysis treatment at for-profit and not-for-profit dialysis facilities is associated with different patterns of clinical benchmark achievement, mortality rates are similar.
doi:10.1186/1471-2369-9-6
PMCID: PMC2474600  PMID: 18582384
22.  Creatinine-Based Glomerular Filtration Rates and Microalbuminuria for Detecting Metabolic Abnormalities in US Adults: The National Health and Nutrition Examination Survey 2003–2004 
American Journal of Nephrology  2007;28(3):431-437.
Background/Aims
Guidelines suggest searching for metabolic complications of chronic kidney disease when glomerular filtration rates (GFR) or urinary albumin tests are abnormal. This study aimed to quantify diagnostic test characteristics of these measures for detecting metabolic abnormalities.
Methods
Subjects were participants aged ≥20 years (n = 7,778) in the US National Health and Nutrition Examination Survey 2003–2004. Low GFR was defined as creatinine-based estimate <60 ml/min per 1.73 m2; abnormal urinary albumin-creatinine ratio as ≥20 mg/dl in men, ≥30 mg/dl in women; and metabolic abnormalities as abnormal potassium, hemoglobin, bicarbonate, phosphorus, or parathyroid hormone levels.
Results
Of adults, 5.66% had low GFR and 8.14% abnormal urinary albumin-creatinine ratio. Overall, 15.09% had ≥ one metabolic abnormality, as did 34.07% with low GFR (p < 0.0001) and 24.27% with abnormal urinary albumin-creatinine ratio (p = 0.0021). Considered as a diagnostic test, the sensitivity, specificity, and positive and negative predictive values of low GFR for detecting ≥1 metabolic abnormality were 0.13, 0.96, 0.34, and 0.86, respectively. Corresponding values for abnormal urinary albumin-creatinine ratio were 0.13, 0.92, 0.24, and 0.86.
Conclusions
A policy of searching for metabolic complications in every adult with low GFR or microalbuminuria has limited diagnostic yield.
doi:10.1159/000112808
PMCID: PMC2786013  PMID: 18097135
Chronic kidney disease; Creatinine; Glomerular filtration rate; Microalbuminuria
23.  Mortality trends among Canadian patients receiving dialysis 
doi:10.1503/cmaj.071247
PMCID: PMC2025611  PMID: 17954895
25.  Laparoscopic Transhiatal Surgery of the Esophagus 
Objective:
Esophagectomy is an operation with high morbidity and mortality. Its adoption as a minimally invasive operation worldwide has been slow, but the potential benefits of reducing the trauma of surgery need to be considered. Our 30-month experience with transhiatal esophagectomy in a district general hospital is presented herein.
Methods:
Patients were considered for surgery after radiological staging had excluded inoperable disease. Laparoscopic staging was initially performed. Patients with tumors of the esophagus and high-grade dysplasia in a Barrett's esophagus were included.
Results:
Twenty-nine patients were referred for consideration for resectional surgery. Nine underwent outpatient laparoscopy only. Twenty patients (age range, 34 to 78, 15 males:5 females) underwent resectional surgery. Seventeen transhiatal resections were completed, 2 were converted to open procedures, and 1 transhiatal resection of a benign tumor was performed. Median time of surgery was 415 minutes (range, 320 to 480) and blood loss was 300 mL (range, 200 to 350). The median length of postoperative ventilation and critical care stay were 1 (range, 1 to 4) and 4 (range, 2 to 8) days. Median duration of hospitalization was 17 days (range, 10 to 28). Thirty-day mortality was 0; 1 patient who was converted to an open procedure died after a cerebrovascular event on day 34.
Conclusion:
A zero mortality rate for laparoscopic resection and a low-morbidity rate compare well with morbidity and mortality in reported series using this method and open surgery. Laparoscopic transhiatal esophagectomy is an advanced, complex procedure that can be performed safely in a district general hospital setting.
PMCID: PMC3015642  PMID: 16381348
Laparoscopic esophagectomy

Results 1-25 (26)