Influence of Incomplete Death Information on Cumulative Risk Estimates in United States Claims Data

Administrative claims databases often do not capture date or fact of death, so studies using these data may inappropriately treat death as a censoring event-equivalent to other withdrawal reasons-rather than a competing event. We examined 1-, 3-, and 5-year inverse-probability-of-treatment-weighted cumulative risks of a composite cardiovascular outcome among 34,527 initiators of telmisartan (exposure) and ramipril (referent) ages ≥55 in Optum claims from 2003 to 2020. Differences in cumulative risks of the cardiovascular endpoint due to censoring of death (cause-specific), as compared to treating death as a competing event (sub-distribution), increased with greater follow-up time and older age, where event and mortality risks were higher. Among ramipril users (selected results), 5-year cause-specific and sub-distribution cumulative risk estimates per 100, respectively, were 16.4 (95% CI 15.3, 17.5) and 16.2 (95% CI 15.1, 17.3) among ages 55-64 (difference=0.2) and were 43.2 (95% CI 41.3, 45.2) and 39.7 (95% CI 37.9, 41.4) among ages ≥75 (difference=3.6). Plasmode simulation results demonstrated the differences in cause-specific versus sub-distribution cumulative risks to increase with increasing mortality rate. We suggest researchers consider the cohort's baseline mortality risk when deciding whether real-world data with incomplete death information can be used without concern.

Pragmatic considerations for negative control outcome studies to guide non-randomized comparative analyses: A narrative review

This narrative review describes the application of negative control outcome (NCO) methods to assess potential bias due to unmeasured or mismeasured confounders in non-randomized comparisons of drug effectiveness and safety. An NCO is assumed to have no causal relationship with a treatment under study while subject to the same confounding structure as the treatment and outcome of interest; an association between treatment and NCO then reflects the potential for uncontrolled confounding between treatment and outcome. We focus on two recently completed NCO studies that assessed the comparability of outcome risk for patients initiating different osteoporosis medications and lipid-lowering therapies, illustrating several ways in which confounding may result. In these studies, NCO methods were implemented in claims-based data sources, with the results used to guide the decision to proceed with comparative effectiveness or safety analyses. Based on this research, we provide recommendations for future NCO studies, including considerations for the identification of confounding mechanisms in the target patient population, the selection of NCOs expected to satisfy required assumptions, the interpretation of NCO effect estimates, and the mitigation of uncontrolled confounding detected in NCO analyses. We propose the use of NCO studies prior to initiating comparative effectiveness or safety research, providing information on the potential presence of uncontrolled confounding in those comparative analyses. Given the increasing use of non-randomized designs for regulatory decision-making, the application of NCO methods will strengthen study design, analysis, and interpretation of real-world data and the credibility of the resulting real-world evidence. This article is protected by copyright. All rights reserved.

A medicare database analysis of practice patterns in patients with mantle cell lymphoma

INTRODUCTION

Although treatment approaches to younger fit patients with mantle cell lymphoma (MCL) are well-described, the optimal treatment of older or less fit patients with varying comorbidities is less clear. The objectives of this study were to examine first-line treatment patterns, and the impact of comorbidities and age on treatment choices and overall survival (OS) in a large, predominantly older, Medicare population.

PATIENTS AND METHODS

In Medicare data from 1/1/2007-8/31/2015, 3,008 patients with MCL were identified. Data on age, gender, race, Charlson comorbidities, Charlson comorbidity index (CCI), timing of injectable MCL therapies, and OS were collected and analyzed.

RESULTS

Median age of the study population was 75.5 (range, 33-107; 25th, 75th: 69.9, 81.5) years. Over half of the individuals had ≥two comorbidities. The CCI was 1-2 in 45%, and 3-4 in 26.6% of patients. Rituximab was the most commonly used agent, regardless of age or comorbidity, in the first 60 days following diagnosis, being administered to 40.2% of patients. In contrast, administration of cyclophosphamide, doxorubicin, vincristine, or bendamustine in the first 60 days after diagnosis was less common (17.9%, 13.1%, 17.2%, and 12%, respectively). Overall survival was 3.23 (range, 0.003-7.668) years, and decreased with increasing number of comorbidities.

DISCUSSION

Our analysis of a real-world patient population with MCL found that older patients have a high rate of comorbidities which impact administered treatment and subsequent OS. Our findings can be used to prospectively guide treatment decisions in these older, frailer, non-transplant-eligible patients, considering the impact of age and comorbidities on such choices.

0690 An Evaluation Of Genioglossus Strengthening On Obstructive Sleep Apnea Treatment Outcomes

Introduction

Obstructive sleep apnea (OSA) is characterized by repetitive episodes of pharyngeal collapse. The genioglossus is a major upper airway dilator muscle thought to be important in OSA pathogenesis. Upper airway (UA) muscle training has reported benefits in some OSA patients. Our goal was to assess the effect of upper airway muscle training on OSA outcomes.

Methods

Sixty five patients with OSA (AHI>10/h) were divided in three subgroups: 1) Treated with auto-CPAP (n=21), 2) Previously failed or refused CPAP therapy (no treatment), (n=24), 3) Currently treated with an oral appliance who still have residual OSA (AHI>10/h), (n=20). All subjects were given a custom-made tongue strengthening device. Within each group we conducted a prospective, randomized, controlled study examining the effect of upper airway muscle training. In each subgroup, subjects were randomized to UA muscle training (volitional protrusion against resistance) or sham group (negligible resistance), with 1:1 ratio over 6 weeks of treatment (twice daily for 20 min/session). In the baseline and the final visit, subjects completed home sleep testing, questionnaires (ESS, PSQI), acoustic pharynogometry, Iowa Oral Performance Instrument (IOPI), and Psychomotor Vigilance Test (PVT).

Results

Results remain blinded; 33 patients received treatment Y and 32 patients received treatment Z. To date, we have not observed a main effect of treatment group on several measures of OSA severity. Some changes in subjective measures over time were observed but difficult to interpret until unblinding occurs.

Conclusion

Treatment of OSA using upper airway muscle training exercises requires further study. Whether muscle training is a viable approach for a definable subset of OSA patients remains unclear.

Support

R01HL085188-05A1 (U.S. NIH Grant/Contract)

Overcoming challenges to data quality in the ASPREE clinical trial

Background

Large-scale studies risk generating inaccurate and missing data due to the complexity of data collection. Technology has the potential to improve data quality by providing operational support to data collectors. However, this potential is under-explored in community-based trials. The Aspirin in reducing events in the elderly (ASPREE) trial developed a data suite that was specifically designed to support data collectors: the ASPREE Web Accessible Relational Database (AWARD). This paper describes AWARD and the impact of system design on data quality.

Methods

AWARD’s operational requirements, conceptual design, key challenges and design solutions for data quality are presented. Impact of design features is assessed through comparison of baseline data collected prior to implementation of key functionality (n = 1000) with data collected post implementation (n = 18,114). Overall data quality is assessed according to data category.

Results

At baseline, implementation of user-driven functionality reduced staff error (from 0.3% to 0.01%), out-of-range data entry (from 0.14% to 0.04%) and protocol deviations (from 0.4% to 0.08%). In the longitudinal data set, which contained more than 39 million data values collected within AWARD, 96.6% of data values were entered within specified query range or found to be accurate upon querying. The remaining data were missing (3.4%). Participant non-attendance at scheduled study activity was the most common cause of missing data. Costs associated with cleaning data in ASPREE were lower than expected compared with reports from other trials.

Conclusions

Clinical trials undertake complex operational activity in order to collect data, but technology rarely provides sufficient support. We find the AWARD suite provides proof of principle that designing technology to support data collectors can mitigate known causes of poor data quality and produce higher-quality data. Health information technology (IT) products that support the conduct of scheduled activity in addition to traditional data entry will enhance community-based clinical trials. A standardised framework for reporting data quality would aid comparisons across clinical trials.

Trial registration

International Standard Randomized Controlled Trial Number Register, ISRCTN83772183. Registered on 3 March 2005.

The aspirin in reducing events in the elderly trial: Statistical analysis plan

Rationale Aspirin has positive and negative effects on a number of age-related chronic conditions and there is uncertainty regarding its role in primary prevention in people aged 70 years and over. Aims To assess whether daily active treatment of 100 mg enteric-coated aspirin will extend the duration of disability-free life in healthy older participants. Design A double-blind, randomized, placebo-controlled primary prevention trial undertaken in Australia and the United States with careful adjudication of endpoints including stroke. Study outcome In Australia 16,703 individuals were recruited through general practices across five states and territories, and in the United States, 2411 participants were recruited through 34 clinical sites across the country. Follow-up of participants will finish at the end of 2017 with average follow-up exceeding 4.25 years per person. Discussion The statistical analysis plan for ASPREE, finalized after closure of recruitment but before the end of patient follow-up, outlines the primary analyses and a range of subgroup and sensitivity analyses. (International Standard Randomized Controlled Trial Number Register ISRCTN83772183 and clinicaltrials.gov Number NCT01038583).

The impact of Agent Orange exposure on prognosis and management in patients with chronic lymphocytic leukemia: a National Veteran Affairs Tumor Registry Study

Exposure to Agent Orange (AO) has been associated with the development of chronic lymphocytic leukemia (CLL). We performed a retrospective study of 2052 Vietnam veterans identified in the National VA Tumor Registry to assess the impact of AO exposure on CLL prognosis, treatment and survival. Prognostic factors did not differ based on exposure. Veterans exposed to AO were diagnosed younger (63.2 vs. 70.5 years, p < .0001) and had longer overall survival (median not reached vs. 91 months, p < .001). This prolonged survival was in the subgroups of patients aged 60-69 years (p< .0001) and those with 11q deletion (p < .0001). Those exposed to AO were more likely to be treated with fludarabine, chlorambucil and rituximab (38 vs. 21%, p < .001) and bendamustine plus rituximab (25 vs. 18%, p = 0.039) as first line therapy. Exposure to AO was not associated with either poor prognostic factors or shortened overall survival in our large veteran population with CLL.

‘Death... more desirable than life’? The human skeletal record and toxicological implications of ancient copper mining and smelting in Wadi Faynan, southwestern Jordan

Skeletal material from 36 people, dating from the early Christian era, who lived by or worked in the notorious Roman copper mines of Phaeno, were analysed to determine their exposure to copper and lead. We demonstrate that many of the bones analysed had a substantially higher concentration of these cations than modern individuals exposed to metals through industrial processes. Health, toxicological and environmental implications of these data are reviewed.

Prognostic Value of Serial Changes in High-Sensitivity Cardiac Troponin I and T over 3 Months Using Reference Change Values in Hemodialysis Patients

INTRODUCTION

Serial changes in cardiac troponin in hemodialysis (HD) patients have uncertain clinical implications. We evaluated associations of adverse outcomes in HD patients with reference change value (RCV) data and tertile concentrations for cardiac troponin I (cTnI) and cTnT measured by high-sensitivity (hs) assays.

METHODS

RCV data and tertiles for hs-cTnI and hs-cTnT were determined from plasma samples collected 3 months apart in 677 stable outpatient HD patients and assessed for their associations with adverse outcomes using adjusted Cox models. Primary outcomes were all-cause mortality and sudden cardiac death (SCD).

RESULTS

During a median follow-up of 23 months, 18.6% of patients died. RCVs were: hs-cTnI +37% and −30%; hs-cTnT +25% and −20%. Patients with serial hs-cTnI and hs-cTnT changes &gt;RCV (increase or decrease) had all-cause mortality of 25.2% and 23.8% respectively, compared to 15.0% and 16.5% with changes ≤RCV [adjusted hazard ratios (aHRs): 1.9, P = 0.0003 and 1.7, P = 0.0066), respectively]. Only hs-cTnI changes &gt;RCV were predictive of SCD (aHR 2.6, P = 0.005). hs–Cardiac troponin changes &gt;RCV improved all-cause mortality prognostication compared to changes ≤RCV in tertile 2: hs-cTnI aHR, 2.70 (P = 0.003); hs-cTnT aHR, 1.98 (P = 0.043). The aHR of changes in hs-cTnI in tertile 2 &gt;RCV for SCD was 5.62 (P = 0.039).

CONCLUSIONS

Changes over 3 months in hs-cTnI and hs-cTnT of &gt;RCV identified patients at greater risk of all-cause mortality, and for hs-cTnI were also predictive of SCD. Among patients with middle tertile cardiac troponin concentrations, hs-cTnI changes &gt;RCV provided additive prognostic value for both SCD and all-cause mortality, whereas those for hs-cTnT provided additive prognostic value only for all-cause mortality.

High one year mortality in adults with sickle cell disease and end-stage renal disease

Adequate pre-dialysis care reduces mortality among end-stage renal disease (ESRD) patients. We tested the hypothesis that individuals with ESRD due to sickle cell disease (SCD-ESRD) receiving pre-ESRD care have lower mortality compared to individuals without pre-ESRD care. We examined the association between mortality and pre-ESRD care in incident SCD-ESRD patients who started haemodialysis between 1 June, 2005 and 31 May, 2009 using data provided by the Centers for Medicare and Medicaid Services (CMS). SCD-ESRD was reported for 410 (0·1%) of 442 017 patients. One year after starting dialysis, 108 (26·3%) patients with incident ESRD attributed to SCD died; the hazard ratio (HR) for mortality among patients with SCD-ESRD compared to those without SCD as the primary cause of renal failure was 2·80 (95% confidence interval [CI] 2·31-3·38). Patients with SCD-ESRD receiving pre-dialysis nephrology care had a lower death rate than those with SCD-ESRD who did not receive pre-dialysis nephrology care (HR = 0·67, 95% CI 0·45-0·99). The one-year mortality rate following an ESRD diagnosis was almost three times higher in individuals with SCD when compared to those without SCD but with ESRD and could be attenuated by pre-dialysis nephrology care.

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.

An instrumental variable analysis of the impact of practice guidelines on improving quality of care and diabetes-related outcomes in the elderly Medicare population

The effect of the diabetes practice guideline recommending >or=2 HbA1c tests annually on diabetes-related outcomes was evaluated using Medicare claims data. The study population included 1998 and 1999 incident diabetes patients aged >or= 67 years, who were Medicare eligible and without known diabetes-related complications at baseline. Number of HbA1c tests was measured 1 year after diabetes incidence. All-cause death and diabetes complications were identified during follow-up, through December 2003. The analysis was conducted with an instrumental variable method and a bivariate probit model, controlling for individual, social, and health care system characteristics. Among 13 033 patients, 27.1% followed the practice guideline. Receiving >or=2 HbA1c tests annually was significantly associated with a decrease in probability of 28.8 percentage points for macrovascular complications, 28.7 for atherosclerotic heart disease, and 23.1 for chronic kidney disease or end-stage renal disease in the 4-year follow-up period.

The 'human revolution' in lowland tropical Southeast Asia: the antiquity and behavior of anatomically modern humans at Niah Cave (Sarawak, Borneo)

Recent research in Europe, Africa, and Southeast Asia suggests that we can no longer assume a direct and exclusive link between anatomically modern humans and behavioral modernity (the 'human revolution'), and assume that the presence of either one implies the presence of the other: discussions of the emergence of cultural complexity have to proceed with greater scrutiny of the evidence on a site-by-site basis to establish secure associations between the archaeology present there and the hominins who created it. This paper presents one such case study: Niah Cave in Sarawak on the island of Borneo, famous for the discovery in 1958 in the West Mouth of the Great Cave of a modern human skull, the 'Deep Skull,' controversially associated with radiocarbon dates of ca. 40,000 years before the present. A new chronostratigraphy has been developed through a re-investigation of the lithostratigraphy left by the earlier excavations, AMS-dating using three different comparative pre-treatments including ABOX of charcoal, and U-series using the Diffusion-Absorption model applied to fragments of bones from the Deep Skull itself. Stratigraphic reasons for earlier uncertainties about the antiquity of the skull are examined, and it is shown not to be an 'intrusive' artifact. It was probably excavated from fluvial-pond-desiccation deposits that accumulated episodically in a shallow basin immediately behind the cave entrance lip, in a climate that ranged from times of comparative aridity with complete desiccation, to episodes of greater surface wetness, changes attributed to regional climatic fluctuations. Vegetation outside the cave varied significantly over time, including wet lowland forest, montane forest, savannah, and grassland. The new dates and the lithostratigraphy relate the Deep Skull to evidence of episodes of human activity that range in date from ca. 46,000 to ca. 34,000 years ago. Initial investigations of sediment scorching, pollen, palynomorphs, phytoliths, plant macrofossils, and starch grains recovered from existing exposures, and of vertebrates from the current and the earlier excavations, suggest that human foraging during these times was marked by habitat-tailored hunting technologies, the collection and processing of toxic plants for consumption, and, perhaps, the use of fire at some forest-edges. The Niah evidence demonstrates the sophisticated nature of the subsistence behavior developed by modern humans to exploit the tropical environments that they encountered in Southeast Asia, including rainforest.

The potential risk from 222radon posed to archaeologists and earth scientists: reconnaissance study of radon concentrations, excavations, and archaeological shelters in the Great Cave of Niah, Sarawak, Malaysia

This reconnaissance study of radon concentrations in the Great Cave of Niah in Sarawak shows that in relatively deep pits and trenches in surficial deposits largely covered by protective shelters with poor ventilation, excavators are working in a micro-environment in which radon concentrations at the ground surface can exceed those of the surrounding area by a factor of > x 2. Although radon concentrations in this famous cave are low by world standards (alpha track-etch results ranging from 100 to 3075 Bq m(-3)), they still may pose a health risk to both excavators (personal dosemeter readings varied from 0.368 to 0.857 mSv for 60 days of work) and cave occupants (1 yr exposure at 15 h per day with an average radon level of 608 Bq m(-3) giving a dose of 26.42 mSv). The data here presented also demonstrate that there is considerable local variation in radon levels in such environments as these.

The impact of residual renal function on graft and patient survival rates in recipients of preemptive renal transplants

BACKGROUND

Transplantation before the initiation of dialysis is associated with prolonged allograft survival. It is unclear if this benefit is attributable to greater residual renal function or to avoidance of dialysis exposure. The authors performed an analysis to determine whether higher renal function at transplant was associated with increased patient and graft survival rates.

METHODS

The authors identified individuals who between 1994 and June 2000 were >or= 18 years and had undergone a living donor renal transplant (Tx) as initial form of renal replacement therapy. Pre-Tx and 6-month estimated glomerular filtration rates (eGFR) were calculated using the 4-variable Modification of Diet in Renal Disease formula. Survival was compared in those with a pre-Tx eGFR >or=15mL/min to those with an eGFR less than 15 mL/min, after adjusting for demographic variables, co-morbidities, and transplant characteristics. Survival rate then was adjusted for calculated propensity scores.

RESULTS

A total of 4,046 patients were included. Mean pre-Tx eGFR was 9.9 mL/min (0.9 to 57.1 mL/min). There was no difference in graft survival rates by strata of eGFR in any of the tested models, even after correcting for propensity score (hazard ratio, 0.95; 95% confidence interval, 0.69 to 1.30). There was no correlation between pre-Tx eGFR and 6-month post-Tx eGFR (r(2) =-0.005).

CONCLUSION

Recipients of preemptive transplants fare equally, regardless of the eGFR at which they receive their transplant. There was no relationship between pre-Tx eGFR and 6-month eGFR, suggesting that post-Tx renal function is independent of the level of pre-Tx renal function. These data suggest that preemptive kidney transplantation should be delayed as long as possible, provided the patient does not have uremic symptoms, and dialysis can be safely avoided.

Diabetes mellitus after kidney transplantation in the United States

New onset diabetes is a major complication after kidney transplantation. However, the incidence, risk factors and clinical relevance of post-transplant diabetes mellitus (PTDM) vary among reports from single-center observational studies and clinical trials. Using data from the United Renal Data System we identified 11 659 Medicare beneficiaries who received their first kidney transplant in 1996-2000. The cumulative incidence of PTDM was 9.1% (95% confidence interval = 8.6-9.7%), 16.0% (15.3-16.7%), and 24.0% (23.1-24.9%) at 3, 12, and 36 months post-transplant, respectively. Using Cox's proportional hazards analysis, risk factors for PTDM included age, African American race (relative risk = 1.68, range: 1.52-1.85, p < 0.0001), Hispanic ethnicity (1.35, range: 1.19-1.54, p < 0.0001), male donor (1.12, range: 1.03-1.21, p = 0.0090), increasing HLA mismatches, hepatitis C infection (1.33, range: 1.15-1.55, p < 0.0001), body mass index >or=30 kg/m2 (1.73, range: 1.57-1.90, p < 0.0001), and the use of tacrolimus as the initial maintenance immunosuppressive medication (1.53, range: 1.29-1.81, p < 0.0001). Factors that reduced the risk for PTDM included the use of mycophenolate mofetil, azathioprine, younger recipient age, glomerulonephritis as a cause of kidney failure, and a college education. As a time-dependent covariate in Cox analyses that also included multiple other risk factors, PTDM was associated with increased graft failure (1.63, 1.46-1.84, p < 0.0001), death-censored graft failure (1.46, 1.25-1.70, p < 0.0001), and mortality (1.87, 1.60-2.18, p < 0.0001). We conclude that high incidences of PTDM are associated with the type of initial maintenance immunosuppression, race, ethnicity, obesity and hepatitis C infection. It is a strong, independent predictor of graft failure and mortality. Efforts should be made to minimize the risk of this important complication.

Diabetes mellitus after kidney transplantation in the United States

New onset diabetes is a major complication after kidney transplantation. However, the incidence, risk factors and clinical relevance of post-transplant diabetes mellitus (PTDM) vary among reports from single-center observational studies and clinical trials. Using data from the United Renal Data System we identified 11 659 Medicare beneficiaries who received their first kidney transplant in 1996-2000. The cumulative incidence of PTDM was 9.1% (95% confidence interval = 8.6-9.7%), 16.0% (15.3-16.7%), and 24.0% (23.1-24.9%) at 3, 12, and 36 months post-transplant, respectively. Using Cox's proportional hazards analysis, risk factors for PTDM included age, African American race (relative risk = 1.68, range: 1.52-1.85, p < 0.0001), Hispanic ethnicity (1.35, range: 1.19-1.54, p < 0.0001), male donor (1.12, range: 1.03-1.21, p = 0.0090), increasing HLA mismatches, hepatitis C infection (1.33, range: 1.15-1.55, p < 0.0001), body mass index >or=30 kg/m2 (1.73, range: 1.57-1.90, p < 0.0001), and the use of tacrolimus as the initial maintenance immunosuppressive medication (1.53, range: 1.29-1.81, p < 0.0001). Factors that reduced the risk for PTDM included the use of mycophenolate mofetil, azathioprine, younger recipient age, glomerulonephritis as a cause of kidney failure, and a college education. As a time-dependent covariate in Cox analyses that also included multiple other risk factors, PTDM was associated with increased graft failure (1.63, 1.46-1.84, p < 0.0001), death-censored graft failure (1.46, 1.25-1.70, p < 0.0001), and mortality (1.87, 1.60-2.18, p < 0.0001). We conclude that high incidences of PTDM are associated with the type of initial maintenance immunosuppression, race, ethnicity, obesity and hepatitis C infection. It is a strong, independent predictor of graft failure and mortality. Efforts should be made to minimize the risk of this important complication.

Inadequate donor size in cadaver kidney transplantation

There have been conflicting reports that kidneys from small donors may be at increased risk for late graft failure if they are transplanted into large recipients. Data from the United States Renal Data System was used to study all first cadaver kidney transplantations performed during the years 1994 to 1999. Donor and recipient body surface area (BSA) combinations were included along with other patient and transplant characteristics in a Poisson analysis of factors associated with early (in the first 4 mo) and late (> or =4 mo) graft failure. The numbers of large (BSA >2.2 m(2)) and medium size (BSA 1.6 to 2.2 m(2)) recipients that received kidneys from small (BSA <1.6 m(2)) donors are less than expected (chi(2) = 118.09; P < 0.0001), suggesting that transplant centers may be refusing some kidneys on the basis of donor-recipient size differences. Large recipients who received kidneys from small donors made up 1.5% of the population and had a 43% (95% CI, 17 to 75%; P = 0.0004) increased risk of late graft failure compared with medium-size recipients who received kidneys from medium-size donors (53.4% of the population). Medium-size recipients who received kidneys from small donors made up 12.0% of the population and had a 16% (95% CI, 6 to 26%; P = 0.0012) increased risk of late graft failure. Disparities in recipient and donor size had similar adverse affects on mortality. Effects of recipient obesity (body mass index) and donor gender on late graft survival were no longer statistically significant after the effects of donor and recipient body size were taken into account. In conclusion, the relative size of the donor and recipient should possibly be taken into account when choosing kidneys for transplantation.

Identification of a mammalian angiopoietin-related protein expressed specifically in liver

Based on searches of EST databases for signal sequences and amphipathic helices, we have identified and cloned an angiopoietin-like gene, ANGPTL3. Multiple tissue Northern blots show that ANGPTL3 is expressed principally in the liver. ANGPTL3 is expressed early during liver development, and expression is maintained in adult liver. Human ANGPTL3 is a 460-amino-acid polypeptide with the characteristic structure of angiopoietins: a signal peptide, an extended helical domain predicted to form dimeric or trimeric coiled-coils, a short linker peptide, and a globular fibrinogen homology domain (FHD). Murine ANGPTL3 is a 455-acid polypeptide encoded by seven exons on mouse chromosome 4, spanning about 11 kb of DNA. ANGPTL3 contains the four conserved cysteines implicated in the intramolecular disulfide bonds within the FHD, but it does not contain two other cysteines that are found within the FHD of angiopoietins 1, 2, and 4. ANGPTL3 also does not contain the characteristic calcium binding motif found in the other angiopoietins. By radiation hybrid mapping and the use of surrounding genes, human ANGPTL3 maps to the 1p31 region.

PDGFbeta receptor blockade inhibits intimal hyperplasia in the baboon

BACKGROUND

We have evaluated the use of a mouse/human chimeric anti-platelet-derived growth factor-beta receptor antibody in combination with heparin to inhibit intimal hyperplasia in the saphenous artery of the baboon after balloon angioplasty.

METHODS AND RESULTS

The study evaluated lesion development in sequential injuries made 28 days apart. Each animal received control treatment after the first injury and antibody/heparin therapy after the second injury to the contralateral artery. The antibody was administered by bolus intravenous injections (10 mg/kg) on study days 1, 4, 8, 15, and 22 and heparin coadministered by continuous intravenous infusion at a dose of 0.13 mg/kg per hour. Morphometric analysis of tissue sections showed a 53% decrease in intimal area after antibody/heparin treatment (P=0.005), corresponding to a 40% decrease in the intima-to-media ratio (P=0.005). Smooth muscle cell proliferation in the injured wall, measured at both 4 and 29 days after balloon injury, were similar in the control and antibody/heparin-treated animals.

CONCLUSIONS

These data suggest that platelet-derived growth factor plays a key role in the development of intimal lesions at sites of acute vascular injury in the nonhuman primate.

Decreasing disability in the 21st century: the future effects of controlling six fatal and nonfatal conditions

OBJECTIVES

This study assessed the effects of reducing fatal and nonfatal health conditions on the number of functionally limited older Americans in the coming decades.

METHODS

Data from the 1990 census and the Longitudinal Study of Aging were used to project the number of functionally limited older Americans from 2001 to 2049, assuming 1% biennial reductions in five conditions that shorten life expectancy (coronary artery disease, stroke, cancer, diabetes, and confusion) and one condition that decreases functional ability (arthritis).

RESULTS

Decreasing the prevalence of arthritis by 1% every 2 years would lead to a much greater reduction in functional limitation between 2001 and 2049 (4 million person-years) than would decreasing any of the other conditions by the same amount. Decreases in two fatal conditions (cancer and coronary artery disease) would lead to increases in functional limitation (0.9 and 0.1 million person-years, respectively).

CONCLUSIONS

Advances against common nonfatal disabling conditions would be more effective than advances against fatal conditions in blunting the large increase in the functionally limited older population anticipated in the 21st century.

Simulation of stochastic micropopulation models--IV. SNAPPERS: model implementation for genetic traits

The current paper concerning stochastic micropopulation simulations describes SNAPPERS, which serves as a framework for simulation models of the genetic transmission of disease. The versions described are implemented using the simulation shell, SUMMERS, which includes the generic commonalities of several micropopulation models. Population members in SNAPPERS move through states related to the individual's status relative to the genotype (phenotype). Features of the model include one or two major loci, polygenic and common familial contribution to the phenotype, assortative mating, and flexibility in defining gene action. The user can select from multiple ascertainment strategies for analysis of simulated families.

Sex differences in early mortality after acute myocardial infarction (the Minnesota Heart Survey)

Although numerous studies indicate that women have a higher early mortality from acute myocardial infarction (AMI) than men, reasons for the difference are largely unexplained. We studied the role of sex in the prognosis of 1,600 patients with AMI aged 30 to 74 years in the population-based Minnesota Heart Survey. A 50% random sample was taken of all AMI patients hospitalized in 1980 and 1985 in the Twin Cities of Minnesota (Minneapolis-St. Paul) (1,168 men, 432 women). A multiple logistic regression model was used for predicting early death (within 28 days) and included baseline characteristics: sex, age, chest pain on admission, history of previous AMI, angina pectoris, coronary artery bypass surgery or hypertension, presence of heart failure, cardiac arrhythmias requiring direct-current shock, diabetes mellitus, valvular disease, cardiomyopathy, and levels of serum enzymes and blood urea nitrogen. Age-adjusted early mortality rate was significantly higher in women than men, but only in those aged < 65 years (12.5% of women vs 6.5% of men, p < 0.01) versus those aged > or = 65 years (19.5% vs 21.6%, p > 0.05). Multivariate analysis also showed that among those < 65 years, female sex was a strong and independent predictor of early death (odds ratio 2.0, 95% confidence interval 1.2 to 3.5, p < 0.01). Rates of coronary angiography, coronary artery bypass surgery, percutaneous transluminal coronary angioplasty, and thrombolysis performed during hospital stay were higher in men, but after adjustment for age, congestive heart failure, and diabetes mellitus, a statistically significant difference persisted only in the frequency of coronary angiography (26% in men vs 17% in women, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Human keratinocytes are a major source of cutaneous platelet-derived growth factor

PDGF has been implicated as one of the principal mitogens involved in cutaneous wound healing. While it has been previously reported that both platelets and monocytes are a source of PDGF in human dermal wound repair, the production of PDGF by human keratinocytes has not yet been described. In this manuscript, we report the production of PDGF by cultured human keratinocytes. Both PDGF A and B chain mRNA can be detected in cultured cells. While only PDGF-AA polypeptide is found in significant levels in keratinocyte-conditioned culture media, all three PDGF isoforms (AA, AB, and BB) are present in detergent-solubilized cell extracts. No evidence of PDGF receptor expression was observed in cultured keratinocytes when analyzed for either mRNA levels or polypeptide expression, suggesting that PDGF does not play an autocrine role in keratinocyte growth. Analysis of cryosections of human cutaneous wounds by immunostaining for PDGF showed that both PDGF A and B chain is constitutively expressed in normal epidermis, as well as in newly reconstituted wound epidermis. No evidence for PDGF receptor polypeptide expression in the epidermis was detected by immunostaining of cryosections.