Variation In Surveillance Research Articles

Surveillance After Surgical and Endovascular Treatment for Peripheral Artery Disease: a Dutch Survey

At present, there is no clear, optimal approach to surveillance after invasive treatment of peripheral artery disease (PAD) in terms of modality, duration, clinical benefit, and cost effectiveness. The ongoing debate on the clinical benefit and cost effectiveness of standard surveillance creates a clear knowledge gap and may result in overtreatment or undertreatment. In this study, a survey was conducted among vascular surgeons in the Netherlands to assess the currently applied surveillance programmes. All vascular surgeons from the Dutch Society for Vascular Surgery received an online survey on follow up after open and endovascular revascularisation in patients with PAD. Surveillance was defined as at least one follow up visit after intervention with or without additional imaging or ankle brachial index (ABI) measurement. Ten types of PAD interventions were surveyed. Surveys were returned by 97 (46.2%) of 210 vascular surgeons, and 76% reported using a routine follow up protocol after an invasive intervention. Clinical follow up only is most commonly performed after femoral endarterectomy (53%). After peripheral bypass surgery, clinical follow up only is applied rarely (4 - 8%). In 6 of the 10 interventions surveyed, duplex ultrasound (DUS) is the most used imaging modality for follow up. After bypass surgery, 76 - 86% of vascular surgeons perform DUS with or without ABI measurement. After endovascular interventions, 21 - 60% perform DUS surveillance. Lifelong surveillance is most applied after aortobifemoral bypass (57%). Surveillance frequency and duration vary greatly within the same intervention. Frequencies range from every 3 months or 6 months to annually. Duration ranges from one time surveillance to lifelong follow up. There is significant practice variation in surveillance after surgical and endovascular treatment of patients with PAD in the Netherlands. We recommend the initiation of prospective studies to evaluate treatment outcomes and to define the clinical need and cost effectiveness of standardised surveillance programmes for patients with PAD.

Clinical variation in surveillance and management of Barrett’s esophagus: A cross-sectional study of gastroenterologists and gastrointestinal surgeons

Appropriate surveillance and treatment of Barrett's esophagus (BE) is vital to prevent disease progression and decrease esophageal adenocarcinoma (EAC)-related mortality. We sought to determine the variation in BE care and identify improvement opportunities. 275 physicians (113 general gastroenterologists, 128 interventional gastroenterologists, 34 gastrointestinal surgeons) cared for 3 simulated patients, one each from 3 BE clinical scenarios: non-dysplastic BE (NDBE), BE indefinite for dysplasia (IND), and BE with low grade dysplasia (LGD), and care scores were measured against societal guidelines. Overall quality-of-care scores ranged from 17% to 85% with mean of 47.9% ± 11.8% for NDBE, 50.8% ± 11.7% for IND, and 52.7% ± 12.2% for LGD. Participants appropriately determined risk of progression 20.3% of the time: 14.4% for NDBE cases, 19.9% for LGD cases, and 26.8% for IND cases (P = .001). Treatment and follow-up care scores averaged 12.9% ± 17.5% overall. For the LGD cases, guideline-recommended twice-daily PPI treatment was ordered only 24.7% of the time. Guideline-based follow-up endoscopic surveillance was done in only 27.7% of NDBE cases and 32.7% of IND cases. For the LGD cases, 45.4% ordered endoscopic eradication therapy while 25.1% chose annual endoscopic surveillance. Finally, participants provided counseling on lifestyle modifications in just 20% of cases. Overall care of patients diagnosed with BE varied widely and showed room for improvement. Specific opportunities for improvement were adherence to guideline recommended surveillance intervals, patient counseling, and treatment selection for LGD. Physicians would potentially benefit from additional BE education, endoscopic advances, and better methods for risk stratification.

Impact of spatiotemporal heterogeneity in COVID-19 disease surveillance on epidemiological parameters and case growth rates

SARS-CoV-2 case data are primary sources for estimating epidemiological parameters and for modelling the dynamics of outbreaks. Understanding biases within case-based data sources used in epidemiological analyses is important as they can detract from the value of these rich datasets. This raises questions of how variations in surveillance can affect the estimation of epidemiological parameters such as the case growth rates. We use standardised line list data of COVID-19 from Argentina, Brazil, Mexico and Colombia to estimate delay distributions of symptom-onset-to-confirmation, -hospitalisation and -death as well as hospitalisation-to-death at high spatial resolutions and throughout time. Using these estimates, we model the biases introduced by the delay from symptom-onset-to-confirmation on national and state level case growth rates (rt) using an adaptation of the Richardson-Lucy deconvolution algorithm. We find significant heterogeneities in the estimation of delay distributions through time and space with delay difference of up to 19 days between epochs at the state level. Further, we find that by changing the spatial scale, estimates of case growth rate can vary by up to 0.13 d−1. Lastly, we find that states with a high variance and/or mean delay in symptom-onset-to-diagnosis also have the largest difference between the rt estimated from raw and deconvolved case counts at the state level. We highlight the importance of high-resolution case-based data in understanding biases in disease reporting and how these biases can be avoided by adjusting case numbers based on empirical delay distributions. Code and openly accessible data to reproduce analyses presented here are available.

Pulmonary surveillance in pediatric hematopoietic stem cell transplant: A multinational multidisciplinary survey.

BackgroundHematopoietic Stem Cell Transplant (HSCT) is an established treatment for malignant and non‐malignant conditions and pulmonary disease is a leading cause of late term morbidity and mortality. Accurate and early detection of pulmonary complications is a critical step in improving long term outcomes. Existing guidelines for surveillance of pulmonary complications post‐HSCT contain conflicting recommendations.AimTo determine the breadth of current practice in monitoring for pulmonary complications of pediatric HSCT.MethodsAn institutional review board approved, online, anonymous multiple‐choice survey was distributed to HSCT and pulmonary physicians from the United States of America and Australasia using the REDcap platform. The survey was developed by members of the American Thoracic Society Working Group on Complications of Childhood Cancer, and was designed to assess patient management and service design.ResultsA total of 40 (34.8%) responses were received. The majority (62.5%) were pulmonologists, and 82.5% were from the United States of America. In all, 67.5% reported having a protocol for monitoring pulmonary complications and 50.0% reported adhering “well” or “very well” to protocols. Pulmonary function tests (PFTs) most commonly involved spirometry and diffusion capacity for carbon monoxide. The frequency of PFTs varied depending on time post‐HSCT and presence of complications. In all, 55.0% reported a set threshold for a clinically significant change in PFT.ConclusionsThese results illustrate current variation in surveillance for pulmonary complications of pediatric HSCT. The results of this survey will inform development of future guidelines for monitoring of pulmonary complications after pediatric HSCT.

Impact of provider type and number of providers on surveillance testing among survivors of head and neck cancers.

Guidelines for follow-up after head and neck cancer (HNC) treatment recommend frequent clinical examinations and surveillance testing. Here, the authors describe real-world follow-up care for HNC survivors and variations in surveillance testing. Using Surveillance, Epidemiology, and End Results (SEER)-Medicare data, this study examined a population-based cohort of HNC survivors between 2001 and 2011 Usage of cross-sectional head and neck imaging (CHNI), chest imaging (CI), positron emission tomography (PET), fiberoptic nasopharyngolaryngoscopy (FNPL), and, in irradiated patients, thyroid function testing (TFT) was captured over 2 consecutive surveillance years. Multivariate modeling with logistic regression analyses was used to assess variations by clinical factors, nonclinical factors, number and types of providers seen and their evolution over time. Among 13,836 HNC survivors, the majority saw a medical, radiation, or surgical oncologist and a primary care provider (PCP; 81.7%) in their first year of surveillance. However, only 58.1% underwent either PET or CHNI, 47.8% underwent CHNI, 64.1% underwent CI, 32.5% underwent PET scans, 55.0% underwent FNPL, and 55.9% underwent TFT. In multivariate analyses, patients who followed up with more providers and those who followed up with both a PCP and an oncologist were more likely to undergo surveillance testing (P < .007). However, adjusting for providers seen did not explain the variations in surveillance testing rates based on age, race, education, income level, and place of residence. Over time, there was a gradual increase in the use of PET scans and TFT during surveillance years. In this large SEER-Medicare data study, only half of HNC survivors received the recommended testing, and greater compliance was seen in those who followed up with both an oncologist and a PCP. More attention is needed to minimize variations in surveillance testing across sociodemographic groups.

Healthcare utilization and hospital variation in cardiac surveillance during breast cancer treatment: a nationwide prospective study in 5000 Dutch breast cancer patients

BackgroundVarious breast cancer (BC) treatments, such as chemotherapy and targeted therapies, increase cardiotoxicity-risk and lead to premature ischemic heart disease and heart failure among survivors. Reducing this adverse risk through early recognition and (preventive) treatment is therefore important. Conversely, we feel that screening for cardiotoxicity is currently insufficiently standardized in daily practice. A fundamental first step in identifying areas of improvement is providing an overview of current practice.ObjectiveThis study aims to describe current cardiac surveillance for women with BC during and after cardiotoxic cancer treatment, using routinely collected hospital data in the Netherlands. The study also describes hospital variation in cardiac surveillance.MethodsThis observational study was performed on claims data provided by Statistics Netherlands. From the data, newly diagnosed BC patients in 2013 (N = 16,040) were selected and followed up until 2015. Healthcare utilization analyses were performed for all cardiac and oncologic healthcare activities but with a specific focus on cardiac surveillance healthcare activities. In addition, differences between types and individual hospitals were evaluated.ResultsAlmost one third of all BC patients received high risk cardiotoxic treatments (N = 5157), but cardiac surveillance was rarely performed. Cardiac care provided to patients mainly consisted of ECGs (52.0%) and MUGA scans (26.5%). Cardiac MRI was performed in 0.7% of the patients, echocardiography in 17.7%, and measurement of Troponin and NT-proBNP in 5.1 and 5.8%, respectively. Moreover, we observed a substantial variation in cardiac surveillance between different hospital types and between individual hospitals.ConclusionThis study shows that women treated for BC with cardiotoxic treatments do not receive recommended cardiac surveillance. Standardized approaches in clinical care are lacking, resulting in low rates of diagnostic testing and a substantial variation in surveillance between hospitals. A structured approach and increased interprofessional collaboration could lead to tailored cardiac surveillance for early detection of cardiotoxicity and therefore start of treatment.

P097: Surveillance mammogram in patients over 70 after mastectomy: Does it make a difference?

Introduction: As the number of breast cancer survivors increase, interest in patient management and surveillance after mastectomy has also increased. There is variation in surveillance between units in terms of duration and frequency of follow-up, clinical and radiographical follow-up or mammography alone and upper age limits. Our current practice is annual mammogram for 5 years for all. With increasing numbers of patients requiring surveillance and finite resources we looked at whether there is a group of patients in whom surveillance mammography may not be necessary.

Current Practices in Ileal Pouch Surveillance for Patients With Ulcerative Colitis: A Multinational, Retrospective Cohort Study.

There are no universally accepted guidelines regarding surveillance of ulcerative colitis [UC] patients after restorative proctocolectomy and ileal pouch-anal anastomosis [IPAA]. There also exists a lack of validated quality assurance standards for performing pouchoscopy. To better understand IPAA surveillance practices in the face of this clinical equipoise, we carried out a retrospective cohort study at five inflammatory bowel disease [IBD] referral centres. Records of patients who underwent IPAA for UC or IBD unclassified [IBDU] were reviewed, and patients with <1-year follow-up after restoration of intestinal continuity were excluded. Criteria for determining the risk of pouch dysplasia formation were collected as well as the use of pouchoscopy, biopsies, and completeness of reports. We included 272 patients. Median duration of pouch follow-up was 10.5 [3.3-23.6] years; 95/272 [35%] had never undergone pouchoscopy for any indication; 191/272 [70%] had never undergone pouchoscopy with surveillance as the specific indication; and 3/26 [12%] high-risk patients had never undergone pouchoscopy. Two cases of adenocarcinoma were identified, occurring in the rectal cuff of low-risk patients. Patients under the care of surgeons appeared more likely to undergo surveillance, but rates of incomplete reporting were higher among surgeons [78%] than gastroenterologists [54%, p = 0.002]. We observed wide variation in surveillance of UC/IBDU-IPAA patients. In addition, the rate of neoplasia formation among 'low-risk' patients was higher than may have been expected. We therefore concur with previous recommendations that pouchoscopy be performed at 1 year postoperatively, to refine risk-stratification based on clinical factors alone. Reports should document findings in all regions of the pouch and biopsies should be taken.

Projecting the end of the Zika virus epidemic in Latin America: a modelling analysis

BackgroundZika virus (ZIKV) emerged in Latin America and the Caribbean (LAC) region in 2013, with serious implications for population health in the region. In 2016, the World Health Organization declared the ZIKV outbreak a Public Health Emergency of International Concern following a cluster of associated neurological disorders and neonatal malformations. In 2017, Zika cases declined, but future incidence in LAC remains uncertain due to gaps in our understanding, considerable variation in surveillance and the lack of a comprehensive collation of data from affected countries.MethodsOur analysis combines information on confirmed and suspected Zika cases across LAC countries and a spatio-temporal dynamic transmission model for ZIKV infection to determine key transmission parameters and projected incidence in 90 major cities within 35 countries. Seasonality was determined by spatio-temporal estimates of Aedes aegypti vectorial capacity. We used country and state-level data from 2015 to mid-2017 to infer key model parameters, country-specific disease reporting rates, and the 2018 projected incidence. A 10-fold cross-validation approach was used to validate parameter estimates to out-of-sample epidemic trajectories.ResultsThere was limited transmission in 2015, but in 2016 and 2017 there was sufficient opportunity for wide-spread ZIKV transmission in most cities, resulting in the depletion of susceptible individuals. We predict that the highest number of cases in 2018 would present within some Brazilian States (Sao Paulo and Rio de Janeiro), Colombia and French Guiana, but the estimated number of cases were no more than a few hundred. Model estimates of the timing of the peak in incidence were correlated (p < 0.05) with the reported peak in incidence. The reporting rate varied across countries, with lower reporting rates for those with only confirmed cases compared to those who reported both confirmed and suspected cases.ConclusionsThe findings suggest that the ZIKV epidemic is by and large over within LAC, with incidence projected to be low in most cities in 2018. Local low levels of transmission are probable, but the estimated rate of infection suggests that most cities have a population with high levels of herd immunity.

Projecting the end of the Zika epidemic in Latin America: A modelling analysis

Background: Zika virus disease emerged in Latin America in early 2015, which had serious implications for population health. In 2016, the World Health Organization declared a cluster of neurological disorders and neonatal malformations associated with Zika cases a Public Health Emergency of International Concern. 2017 incidence has declined, and future disease incidence in Latin America remains uncertain due to gaps in our understanding of the natural history of infection, considerable variation in surveillance and a lack of a comprehensive collation of available data from affected countries. Methods & Materials: This analysis combines publically available data on Zika virus incidence across most Latin American countries and a spatio-temporal dynamic transmission model for Zika virus infection to determine key transmission parameters and likely future incidence in 87 cities. Seasonality was determined by spatio-temporal estimates of Aedes aegypti vector capacity. Country and state-level data are used to infer key model parameters using Monte-Carlo methods, different movement models were tested against the data and the best-fitting parameter combinations were used to estimate incidence within each city. Results: We predict that the highest incidence in 2018 will be observed in Colombia and some Brazilian States (Parana, Sao Paulo, Rio de Janiero and Minas Gerias), but the estimated number of infections will be no more than a few hundred and the incidence risk ratio will be below 0.05. There was limited transmission in 2015, but for most cities 2016 and 2017 provided a sufficient opportunity for ZIKV transmission and populations have been depleted of susceptible individuals. Conclusion: The findings suggest that much of the ZIKV-associated morbidity will be in neonates and children that are born up to the end of 2017. The findings present a challenge to planned ZIKV-specific interventions such as phase III vaccine trials, as we predict substantially lower numbers of infections in 2018.

Controlling pertussis: how can we do it? A focus on immunization

ABSTRACTIntroduction: Pertussis is a highly contagious disease of the respiratory tract which is caused by the bacterium Bordetella pertussis and is most severe in those <1 year of age. A vaccine against pertussis, introduced in the 1950’s, led to a significant decrease in incidence of the disease, but recent increases in outbreaks have been attributed to insufficient vaccine uptake, suboptimal protection conferred by vaccines, and waning immunity after immunization.Areas covered: In this review we discuss the major challenges for controlling pertussis, and what we believe the best strategies are to overcome these challenges, focusing on immunization against pertussis in Europe, but with recommendations that are relevant worldwide.Expert commentary: To provide maximum vaccine coverage we propose a schedule that incorporates immunization of infants, preschoolers, adolescents, adults, and pregnant women. Uptake of vaccines may also vary between populations due to a variety of causes, including hesitancy to vaccinate, so any national strategy to control pertussis should also include sustaining public and healthcare provider confidence in vaccination. Addressing and improving regional variations in surveillance will also help better monitor annual incidence and outbreaks. Looking towards the future, the development of new pertussis vaccines with longer duration of protection would be advantageous.

Practice patterns of surveillance endoscopy in a Veterans Affairs database of 29,504 patients with Barrett's esophagus

Practice guidelines recommend surveillance endoscopy every 2 to 3 years among patients with Barrett's esophagus (BE) to detect early neoplastic lesions. Although surveys report that >95% of gastroenterologists recommend or practice BE surveillance, the extent and patterns of surveillance in clinical practice are unknown. To identify the extent and determinants of endoscopic surveillance among BE patients. Retrospective cohort study. A total of 121 Veterans Affairs facilities nationwide. Veteran patients with BE diagnosed from 2003 to 2009, with follow-up through September 30, 2010. Not an interventional study. The proportions of patients with BE who received any EGD after the index BE EGD date. In the subgroup of patients with at least 6 years of follow-up, we also calculated proportions for regular (EGD during both 3-year intervals), irregular (EGD in only 1 interval), and no surveillance. We examined differences in demographics and clinical and facility factors among these groups in unadjusted and adjusted analyses. We identified 29,504 patients with BE; 97% were men, 83% white, and their mean age was 61.8 years. During a 3.8-year median follow-up period, 45.4% of patients with BE received at least one EGD. Among the subgroup of 4499 patients with BE who had at least 6 years of follow-up, 23.0% had regular surveillance, and 26.7% had irregular surveillance. There was considerable facility-level variation in percentages with surveillance EGD across the 112 facilities and by geographic region of these facilities. Demographic and clinical factors did not explain these variations. Patients with at least one EGD were significantly more likely to be white; to be aged <65 years, with a low level of comorbidity; to have GERD, obesity, dysphagia, or esophageal strictures; to have more outpatient visits; and to be seen in smaller hospitals (<87 beds) than those without any EGD. There might be misclassification of BE and surveillance EGD. Lack of pathology data on dysplasia, which dictates surveillance intervals. Endoscopic surveillance for BE is considerably less commonly practiced in Veterans Affairs facilities than is self-reported by physicians. Although several clinical factors are associated with variations in surveillance, facility-level factors play a large role. The comparative effectiveness of the different practice-based surveillance patterns needs to be examined.

1475 QUALITY OF CARE FOR PATIENTS WITH HIGH-GRADE NON-MUSCLE-INVASIVE BLADDER CANCER

You have accessJournal of UrologyBladder Cancer: Superficial II1 Apr 20101475 QUALITY OF CARE FOR PATIENTS WITH HIGH-GRADE NON-MUSCLE-INVASIVE BLADDER CANCER Karim Chamie, Christopher Saigal, Jan Hanley, Badrinath Konety, Mark Litwin, and Urologic Diseases in America Projectb Karim ChamieKarim Chamie Los Angeles, CA More articles by this author , Christopher SaigalChristopher Saigal Los Angeles, CA More articles by this author , Jan HanleyJan Hanley Santa Monica, CA More articles by this author , Badrinath KonetyBadrinath Konety Minneapolis, MN More articles by this author , Mark LitwinMark Litwin Los Angeles, CA More articles by this author , and Urologic Diseases in America Projectb More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2010.02.1190AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Best practice guidelines that address surveillance, staging and treatment strategies for patients with high-grade non-muscle-invasive bladder cancer have been established to minimize tumor recurrence and progression. We sought to determine the frequency of adherence and identify the variables that drive compliance with these guidelines. METHODS Using linked SEER-Medicare data, we identified 8,513 patients with an incident diagnosis of high-grade non-muscle-invasive bladder cancer from 1992 to 2002. The dependent variables included surveillance cystoscopy, urine cytology, upper tract imaging, and the use of intravesical therapy— Bacillus Calmette-Guérin (BCG) and Mitomycin C. The independent variables included age, gender, race, marital status, patient comorbidities, and SEER registry. The American Urological Association, European Association of Urology and the National Comprehensive Cancer Network guidelines were used to generate the surveillance, staging and treatment strategies for patients with bladder cancer. Univariate and multiple logistic regression analyses were performed to measure associations between the independent variables and the surveillance, staging and treatment strategies. RESULTS Compliance was strongest for upper tract imaging (98%) and lowest for postoperative Mitomycin C (3%)(Table 1). Approximately 15% and 22% of patients underwent the recommended surveillance cystoscopies and urine cytologies, respectively. Approximately 39% of patients received at least a single dose of BCG therapy, with only 12% receiving all six instillations. Sociodemographic factors (age, race and marital status) were independently associated with variation in adherence to surveillance (cystoscopy and urine cytology) and treatment strategies (Mitomycin and BCG intravesical instillations). Comorbidity was associated with variation in surveillance but not treatment strategies. Table 1. Univariate analysis of the association between sociodemographic factors and surveillance, staging and treatment strategies for patients with high-grade non-muscle-invasive bladder cancer. Variables Cystoscopy Cytology Upper Tract Imaging Mitomycin C BCG Age 65 - 70 17% 30% 98% 3% 11% 71 -75 18% 26% 98% 3% 12% 76 - 80 15% 24% 98% 2% 13% >80 10% 14% 98% 2% 8% p-value <0.001 p-value <0.001 p-value 0.73 p-value 0.03 p-value <0.001 Gender Male 14% 22% 98% 3% 11% Female 16% 22% 98% 2% 11% p-value 0.13 p-value 0.37 p-value 0.89 p-value 0.18 p-value 0.02 Race White 15% 23% 98% 3% 11% Black 9% 25% 99% 3% 9% Hispanic 12% 19% 97% 2% 11% Other 19% 14% 99% 6% 13% p-value 0.006 p-value 0.001 p-value 0.48 p-value 0.003 p-value 0.15 Marital Status Married 16% 24% 98% 3% 11% Other 12% 19% 98% 2% 10% p-value <0.001 p-value <0.001 p-value 0.76 p-value 0.04 p-value <0.001 Comorbidity 0 17% 24% 97% 3% 11% 1 13% 21% 98% 3% 11% ≥2 9% 16% 99% 3% 9% p-value <0.001 p-value <0.001 p-value <0.001 p-value 0.77 p-value 0.13 CONCLUSIONS Evidence from best practice guidelines is derived from randomized control trials (RCT), observational studies and from expert opinions. While many patients with high-grade non-muscle-invasive bladder cancer do not receive the care as recommended by these guidelines, the greatest deficiency is from those that have been shown to reduce recurrence and progression in RCT (intravesical therapy). © 2010 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 183Issue 4SApril 2010Page: e568-e569 Advertisement Copyright & Permissions© 2010 by American Urological Association Education and Research, Inc.MetricsAuthor Information Karim Chamie Los Angeles, CA More articles by this author Christopher Saigal Los Angeles, CA More articles by this author Jan Hanley Santa Monica, CA More articles by this author Badrinath Konety Minneapolis, MN More articles by this author Mark Litwin Los Angeles, CA More articles by this author Urologic Diseases in America Projectb More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Use of Surveillance for Hepatocellular Carcinoma Among Patients With Cirrhosis in the United States

Surveillance for hepatocellular carcinoma (HCC) in patients with cirrhosis is recommended but may not be performed. The extent and determinants of HCC surveillance are unknown. We conducted a population-based United States cohort study of patients over 65 years of age to examine use and determinants of prediagnosis surveillance in patients with HCC who were previously diagnosed with cirrhosis. Patients diagnosed with HCC during 1994-2002 were identified from the linked Surveillance, Epidemiology, and End-Results registry-Medicare databases. We identified alpha-fetoprotein (AFP) and ultrasound tests performed for HCC surveillance, and examined factors associated with surveillance. We identified 1,873 HCC patients with a prior diagnosis of cirrhosis. In the 3 years before HCC, 17% received regular surveillance and 38% received inconsistent surveillance. In a subset of 541 patients in whom cirrhosis was recorded for 3 or more years prior to HCC, only 29% received routine surveillance and 33% received inconsistent surveillance. Among all patients who received regular surveillance, approximately 52% received both AFP and ultrasound, 46% received AFP only, and 2% received ultrasound only. Patients receiving regular surveillance were more likely to have lived in urban areas and had higher incomes than those who did not receive surveillance. Before diagnosis, approximately 48% of patients were seen by a gastroenterologist/hepatologist or by a physician with an academic affiliation; they were approximately 4.5-fold and 2.8-fold, respectively, more likely to receive regular surveillance than those seen by a primary care physician only. Geographic variation in surveillance was observed and explained by patient and physician factors. Less than 20% of patients with cirrhosis who developed HCC received regular surveillance. Gastroenterologists/hepatologists or physicians with an academic affiliation are more likely to perform surveillance.

Time budget variation in relation to flock size in carrion crows, Corvus corone corone

Abstract. Time budgets of carrion crows feeding in flocks of variable size were recorded in a field experiment. Variation in surveillance, successful and unsuccessful pecking, walking and aggression was analysed in relation to flock size while controlling for the effects of confounding variables (time of day, food quality and density, temperature, observer). Time devoted to surveillance and surveillance rate decreased non-linearly with increasing flock size, while time elapsing between two successive surveillance episodes increased linearly with flock size. Surveillance behaviour did not vary with food density. Surveillance was significantly higher when a predator was flying over the flock or had just disappeared than for apparently undisturbed crows. Feeding rates reached a maximum in flocks of 10 crows, decreased in larger flocks and increased monotonically with food density. The number of aggressive encounters/min was positively correlated with flock size but was independent of food density. In the range of flock sizes considered (1-17 birds), crows benefited from being in a flock in terms of both increased feeding efficiency and, presumably, increased surveillance in the flock. It is also suggested that the increase in bird density with flock size, rather than the increase in flock size per se, was responsible for higher levels of aggression in large flocks.