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The additive nonparametric and semiparametric Aalen model as the rate function for a counting process.

https://arctichealth.org/en/permalink/ahliterature188979
Source
Lifetime Data Anal. 2002 Sep;8(3):247-62
Publication Type
Article
Date
Sep-2002
Author
Thomas H Scheike
Author Affiliation
Department of Mathematical Sciences, University of Aalborg, Fredrik Bajers Vej 7G, DK-9220 Aalborg, Denmark. ts@math.auc.dk
Source
Lifetime Data Anal. 2002 Sep;8(3):247-62
Date
Sep-2002
Language
English
Publication Type
Article
Keywords
Data Interpretation, Statistical
Denmark
Humans
Liver Diseases - drug therapy - mortality
Models, Statistical
Regression Analysis
Risk assessment
Survival Analysis
Abstract
We use the additive risk model of Aalen (Aalen, 1980) as a model for the rate of a counting process. Rather than specifying the intensity, that is the instantaneous probability of an event conditional on the entire history of the relevant covariates and counting processes, we present a model for the rate function, i.e., the instantaneous probability of an event conditional on only a selected set of covariates. When the rate function for the counting process is of Aalen form we show that the usual Aalen estimator can be used and gives almost unbiased estimates. The usual martingale based variance estimator is incorrect and an alternative estimator should be used. We also consider the semi-parametric version of the Aalen model as a rate model (McKeague and Sasieni, 1994) and show that the standard errors that are computed based on an assumption of intensities are incorrect and give a different estimator. Finally, we introduce and implement a test-statistic for the hypothesis of a time-constant effect in both the non-parametric and semi-parametric model. A small simulation study was performed to evaluate the performance of the new estimator of the standard error.
PubMed ID
12182121 View in PubMed
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Biliary atresia in Canada: the effect of centre caseload experience on outcome.

https://arctichealth.org/en/permalink/ahliterature142896
Source
J Pediatr Gastroenterol Nutr. 2010 Jul;51(1):61-5
Publication Type
Article
Date
Jul-2010
Author
Richard A Schreiber
Collin C Barker
Eve A Roberts
Steven R Martin
Author Affiliation
Division of Gastroenterology, Department of Pediatrics, Faculty of Medicine, University of British Columbia, Vancouver, BC. rschreiber@cw.bc.ca
Source
J Pediatr Gastroenterol Nutr. 2010 Jul;51(1):61-5
Date
Jul-2010
Language
English
Publication Type
Article
Keywords
Adolescent
Biliary Atresia - mortality - surgery
Canada - epidemiology
Case Management - standards
Child
Delivery of Health Care - standards
Female
Hospitals - standards - utilization
Humans
Infant
Liver Failure - mortality - surgery
Liver Transplantation - mortality
Male
Ostomy - methods - mortality
Prognosis
Quality of Health Care
Survival Analysis
Treatment Outcome
Abstract
: Biliary atresia (BA) is a leading cause of end-stage paediatric liver disease. Standard BA treatment is sequential surgery with an initial Kasai procedure (KP) followed by liver transplant (LT) for patients who progress to liver failure. A key determinant for the post-KP patient survival with their native liver is patient age at KP (older age, poorer outcome). Recently, European studies have reported that caseload experience influences prognosis with centres managing 3 cases per year). Overall patient, post-KP native liver, and LT survivals were compared between centres. Outcome parameters were reevaluated for patients grouped by the largest Canadian centre (>5 cases per year) and all other centres (
PubMed ID
20543720 View in PubMed
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Choosing the net survival method for cancer survival estimation.

https://arctichealth.org/en/permalink/ahliterature265832
Source
Eur J Cancer. 2015 Jun;51(9):1123-9
Publication Type
Article
Date
Jun-2015
Author
Karri Seppä
Timo Hakulinen
Arun Pokhrel
Source
Eur J Cancer. 2015 Jun;51(9):1123-9
Date
Jun-2015
Language
English
Publication Type
Article
Keywords
Colonic Neoplasms - mortality
Female
Finland - epidemiology
Follow-Up Studies
Gallbladder Neoplasms - mortality
Humans
Liver Neoplasms - mortality
Male
Models, Statistical
Neoplasms - mortality
Registries - statistics & numerical data
Survival Analysis
Time Factors
Abstract
A new net survival method has been introduced by Pohar Perme et al. (2012 [4]) and recommended to substitute the relative survival methods in current use for evaluating population-based cancer survival.
The new method is based on the use of continuous follow-up time, and is unbiased only under non-informative censoring of the observed survival. However, the population-based cancer survival is often evaluated based on annually or monthly tabulated follow-up intervals. An empirical investigation based on data from the Finnish Cancer Registry was made into the practical importance of the censoring and the level of data tabulation. A systematic comparison was made against the earlier recommended Ederer II method of relative survival using the two currently available computer programs (Pohar Perme (2013) [10] and Dickman et al. (2013) [11]).
With exact or monthly tabulated data, the Pohar-Perme and the Ederer II methods give, on average, results that are at five years of follow-up less than 0.5% units and at 10 and 14 years 1-2% units apart from each other. The Pohar-Perme net survival estimator is prone to random variation and may result in biased estimates when exact follow-up times are not available or follow-up is incomplete. With annually tabulated follow-up times, estimates can deviate substantially from those based on more accurate observations, if the actuarial approach is not used.
At 5 years, both the methods perform well. In longer follow-up, the Pohar-Perme estimates should be interpreted with caution using error margins. The actuarial approach should be preferred, if data are annually tabulated.
PubMed ID
24183462 View in PubMed
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[Chronic viral hepatitis in St.Petersburg].

https://arctichealth.org/en/permalink/ahliterature112719
Source
Zh Mikrobiol Epidemiol Immunobiol. 2013 Mar-Apr;(2):44-50
Publication Type
Article
Author
A G Rakhmanova
A A Iakovlev
V A Tsinzerling
Source
Zh Mikrobiol Epidemiol Immunobiol. 2013 Mar-Apr;(2):44-50
Language
Russian
Publication Type
Article
Keywords
Hepacivirus - isolation & purification
Hepatitis B virus - isolation & purification
Hepatitis B, Chronic - complications - mortality - pathology - virology
Hepatitis C, Chronic - complications - mortality - pathology - virology
Hepatitis D, Chronic - complications - mortality - pathology - virology
Hepatitis Delta Virus - isolation & purification
Humans
International Classification of Diseases
Liver - pathology - virology
Liver Cirrhosis - etiology - mortality - virology
Russia - epidemiology
Survival Analysis
Abstract
Morbidity data on chronic viral hepatitis including cirrhotic stages of disease and lethality indexes in St. Petersburg are provided. The necessity of isolation in ICD- 10 and statistical accounting of chronic viral hepatitis diagnosis with outcome into cirrhosis (cirrhotic stage) is shown. During use of viral etiology liver cirrhosis diagnosis the disease is registered in the structure of liver diseases which does not allow to have data on unfavorable outcomes of chronic viral hepatitis and for complete morbidity accounting.
PubMed ID
23805672 View in PubMed
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Clinical course and prognosis of never-smokers with severe alpha-1-antitrypsin deficiency (PiZZ).

https://arctichealth.org/en/permalink/ahliterature92621
Source
Thorax. 2008 Dec;63(12):1091-5
Publication Type
Article
Date
Dec-2008
Author
Tanash H A
Nilsson P M
Nilsson J-A
Piitulainen E.
Author Affiliation
Department of Respiratory Medicine, Malmö University Hospital, Entrance 35, S-205 02, Malmö, Sweden. hanan.tanash@med.lu.se
Source
Thorax. 2008 Dec;63(12):1091-5
Date
Dec-2008
Language
English
Publication Type
Article
Keywords
Adult
Aged
Aged, 80 and over
Cause of Death
Female
Forced Expiratory Volume - physiology
Humans
Liver Diseases - complications - mortality - physiopathology
Male
Middle Aged
Prognosis
Respiratory Tract Diseases - complications - mortality - physiopathology
Survival Analysis
Sweden - epidemiology
Vital Capacity - physiology
Young Adult
alpha 1-Antitrypsin Deficiency - complications - mortality - physiopathology
Abstract
BACKGROUND: Previous studies of non-smoking individuals with severe alpha(1)-antitrypsin deficiency (PiZZ) have been sparse and included only a limited number of individuals, mostly identified by respiratory symptoms. The aim of this study was to estimate the prognosis of non-smoking PiZZ individuals and to analyse the most common causes of death by including a large number of individuals who had been identified by other means than respiratory symptoms. METHODS: The study included 568 non-smoking PiZZ subjects who were selected from the Swedish National AAT Deficiency Registry and followed up from 1991 to September 2007. Of these, 156 (27%) were identified by respiratory symptoms (respiratory cases) and 412 were identified by extrapulmonary symptoms or screening (non-respiratory cases). RESULTS: 93 subjects (16%) died during the follow-up period. The specific standardised mortality rate (SMR) for the whole study population was 2.32 (95% CI 1.87 to 2.83) with no significant difference between men and women. The SMR was 2.55 (95% CI 1.91 to 2.83) for the respiratory cases and 2.07 (95% CI 1.49 to 2.81) for the non-respiratory cases. Further calculation of SMR for subgroups in the non-respiratory cases showed that the SMR was 0.70 (95% CI 0.14 to 2.04) for individuals identified by family/population screening. Emphysema and liver cirrhosis were the most common causes of death (45% and 28%, respectively). Malignant transformation was found in 38% of the cases with cirrhosis. CONCLUSION: Non-smoking PiZZ individuals identified by screening do not have an increased mortality risk compared with the Swedish general population.
PubMed ID
18682522 View in PubMed
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Clinical features in hepatocellular carcinoma and the impact of autopsy on diagnosis. A study of 530 cases from a low-endemicity area.

https://arctichealth.org/en/permalink/ahliterature16595
Source
Hepatogastroenterology. 2005 Nov-Dec;52(66):1798-802
Publication Type
Article
Author
Jerzy Kaczynski
Göran Hansson
Sven Wallerstedt
Author Affiliation
Department of Medicine, Göteborg University, Sahlgren's University Hospital, Sweden.
Source
Hepatogastroenterology. 2005 Nov-Dec;52(66):1798-802
Language
English
Publication Type
Article
Keywords
Adolescent
Adult
Age Distribution
Aged
Aged, 80 and over
Autopsy
Biopsy, Needle
Carcinoma, Hepatocellular - epidemiology - pathology - surgery
Cause of Death
Child
Comparative Study
Endemic Diseases - statistics & numerical data
Female
Hepatectomy - methods
Humans
Immunohistochemistry
Incidence
Liver Function Tests
Liver Neoplasms - epidemiology - pathology - surgery
Male
Middle Aged
Neoplasm Staging
Research Support, Non-U.S. Gov't
Retrospective Studies
Sex Distribution
Survival Analysis
Sweden - epidemiology
Abstract
BACKGROUND/AIMS: Hepatocellular carcinoma (HCC) had been one of the malignancies with the highest reported increase of incidence in Sweden, but during the late 20-year period the incidence has been decreasing. The aims of our study were to state the impact of autopsy on diagnosis and to identify clinical characteristics in HCC. METHODOLOGY: This retrospective study was performed in Göteborg, Sweden and included all cases with a diagnosis of liver cancer from a period with a high autopsy frequency (1958-1979). The cases were reevaluated histopathologically and the autopsy records as well as the case files were scrutinized. RESULTS: The majority (63%) of the 530 biopsy verified cases of HCC were diagnosed unexpectedly at autopsy. Cirrhosis of the liver could be established in 71% of the cases, but was diagnosed or at least clinically suspected before the diagnosis of the tumor only in a minority (19%) of all HCC patients. At presentation, malaise (85%), weight loss (78%), anorexia (67%) and hepatomegaly (84%) were common. The median survival time from diagnosis was one month. In most cases (92%) the cause of death was either directly or indirectly related to HCC and/or underlying liver disease such as advanced tumor disease, hepatic failure and gastrointestinal bleeding. Spontaneous rupture of HCC was the cause of death in 17 cases (3%) CONCLUSIONS: In an unselected population in a low incidence area of HCC, most patients have clinically unknown cirrhosis of the liver and present with vague general paramalignant symptoms. HCC has an extremely poor prognosis. Since HCC, in a majority of cases, remains undiagnosed before death, the autopsy has great impact on the diagnosis. This should be considered in interpretation of results from epidemiological studies.
PubMed ID
16334780 View in PubMed
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Clinical significance of serum bilirubin levels under ursodeoxycholic acid therapy in patients with primary biliary cirrhosis.

https://arctichealth.org/en/permalink/ahliterature203571
Source
Hepatology. 1999 Jan;29(1):39-43
Publication Type
Article
Date
Jan-1999
Author
A M Bonnand
E J Heathcote
K D Lindor
R E Poupon
Author Affiliation
INSERM Unit 21, Villejuif, France.
Source
Hepatology. 1999 Jan;29(1):39-43
Date
Jan-1999
Language
English
Publication Type
Article
Keywords
Bilirubin - blood
Canada
Cholagogues and Choleretics - therapeutic use
Female
Humans
Liver Cirrhosis, Biliary - blood - drug therapy - mortality
Liver Transplantation
Male
Middle Aged
Predictive value of tests
Prognosis
Survival Analysis
Treatment Outcome
United States
Ursodeoxycholic Acid - therapeutic use
Abstract
We determined whether the normalization of serum bilirubin level (SBL) induced by ursodeoxycholic acid (UDCA) therapy was associated with an improved clinical outcome in patients with primary biliary cirrhosis (PBC). We estimated the prognostic values of SBL measured after 6 months of UDCA treatment for survival free of orthotopic liver transplantation (OLT). We used a database of 548 patients with PBC followed in three trials of UDCA. Among UDCA-treated patients, we compared survival free of OLT in patients with normalized SBL (
PubMed ID
9862847 View in PubMed
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Combination of radiofrequency ablation with transarterial chemoembolization for treatment of hepatocellular carcinoma: experience from a Danish tertiary liver center.

https://arctichealth.org/en/permalink/ahliterature279664
Source
Acta Radiol. 2016 Jul;57(7):844-51
Publication Type
Article
Date
Jul-2016
Author
Arindam Bharadwaz
Kirstine Petrea Bak-Fredslund
Gerda Elisabeth Villadsen
Jens Erik Nielsen
Kira Simonsen
Thomas Damgaard Sandahl
Henning Grønbæk
Dennis Tønner Nielsen
Source
Acta Radiol. 2016 Jul;57(7):844-51
Date
Jul-2016
Language
English
Publication Type
Article
Keywords
Aged
Aged, 80 and over
Antibiotics, Antineoplastic - therapeutic use
Carcinoma, Hepatocellular - therapy
Catheter Ablation - methods
Chemoembolization, Therapeutic - methods
Combined Modality Therapy
Denmark
Doxorubicin - therapeutic use
Female
Humans
Liver Neoplasms - therapy
Male
Middle Aged
Patient Selection
Retrospective Studies
Survival Analysis
Treatment Outcome
Abstract
Recent studies have shown that the combination of radiofrequency ablation (RFA) and transarterial chemoembolization (TACE) for unresectable hepatocellular carcinoma (HCC) may offer a survival advantage compared to monotherapy.
To study the effectiveness of combination therapy with RFA and TACE compared to that of TACE alone in a Scandinavian tertiary liver cancer center.
A retrospective study of the patients treated with combination therapy vis-à-vis TACE alone from June 2007 to November 2012 was performed. Eighteen patients were treated with a combination of RFA and TACE with an interval of 1-4 days between the treatments. For comparison, a group of 18 patients treated with TACE as monotherapy in the same time period was matched with the combination group by demographic data, tumor characteristics, biochemical and clinical parameters, and performance status (PS).
Each group consisted of 14 patients with cirrhosis and four without. There were no significant differences between the groups regarding age, gender, tumor characteristics, causes of cirrhosis, levels of bilirubin, creatinine, prothrombin time, Child Pugh score, or World Health Organization (WHO) performance status. The median survival of patients in the RFA?+?TACE combination group was 586 days compared to 296 days in the control group. The difference was not statistically significant (P?=?0.26). However, when we stratified the data for cirrhosis and WHO performance status, patients in the combination group had significantly better survival (P?=?0.024).
Combination therapy with RFA and TACE for unresectable HCC, compared to TACE alone, may offer a survival benefit for a selected group of patients with HCC.
PubMed ID
26342009 View in PubMed
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Complementary and alternative medicine use among general surgery, hepatobiliary surgery and surgical oncology patients.

https://arctichealth.org/en/permalink/ahliterature147668
Source
Can J Surg. 2009 Oct;52(5):422-6
Publication Type
Article
Date
Oct-2009
Author
Colin Schieman
Luke R Rudmik
Elijah Dixon
Francis Sutherland
Oliver F Bathe
Author Affiliation
Department of Surgery, University of Calgary, Calgary, Alta.
Source
Can J Surg. 2009 Oct;52(5):422-6
Date
Oct-2009
Language
English
Publication Type
Article
Keywords
Adult
Aged
Alberta
Attitude to Health
Biliary Tract Neoplasms - mortality - surgery - therapy
Complementary Therapies - utilization
Dietary Supplements - utilization
Female
General Surgery
Health Care Surveys
Humans
Incidence
Liver Neoplasms - mortality - surgery - therapy
Male
Middle Aged
Neoplasms - diagnosis - mortality - surgery - therapy
Oncology Service, Hospital
Patient Participation
Prognosis
Questionnaires
Risk assessment
Survival Analysis
Treatment Outcome
Abstract
The use of complementary and alternative medicine (CAM) is becoming more common, particularly among cancer patients. We sought to define the frequency of CAM use among general surgery, hepatobiliary and surgical oncology patients and to define some of the determinants of CAM use in patients with benign and malignant disease.
We asked all patients attending the clinics of 3 hepatobiliary/surgical oncology surgeons from 2002 to 2005 to voluntarily respond on first and subsequent visits to a questionnaire related to the use of CAM. We randomly selected patients for review.
We reviewed a total of 490 surveys from 357 patients. Overall CAM use was 27%. There was significantly more CAM use among cancer (34%) versus noncancer patients (21%; p = 0.008), and the use of CAM was more common in patients with unresectable cancer (51%) than resectable cancer (22%; p
Notes
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PubMed ID
19865579 View in PubMed
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Cost and health consequences of treatment of primary biliary cirrhosis with ursodeoxycholic acid.

https://arctichealth.org/en/permalink/ahliterature257163
Source
Aliment Pharmacol Ther. 2013 Oct;38(7):794-803
Publication Type
Article
Date
Oct-2013
Author
K M Boberg
T. Wisløff
K S Kjøllesdal
H. Støvring
I S Kristiansen
Author Affiliation
Section for Gastroenterology, Department of Transplantation Medicine, Oslo University Hospital, Rikshospitalet, Oslo, Norway. kboberg@ous-hf.no
Source
Aliment Pharmacol Ther. 2013 Oct;38(7):794-803
Date
Oct-2013
Language
English
Publication Type
Article
Keywords
Aged
Canada
Cost-Benefit Analysis
Female
Follow-Up Studies
Health Care Costs
Humans
Life expectancy
Liver Cirrhosis, Biliary - drug therapy - economics - mortality
Liver Transplantation
Male
Markov Chains
Middle Aged
Norway
Randomized Controlled Trials as Topic
Survival Analysis
Time Factors
Ursodeoxycholic Acid - administration & dosage - economics - therapeutic use
Abstract
Long-term use of ursodeoxycholic acid (UDCA) is the recommended therapy in primary biliary cirrhosis (PBC). The lifetime effectiveness and cost-effectiveness of UDCA in PBC have, however, not been assessed.
To estimate the health outcomes and lifetime costs of a Norwegian cohort of PBC patients on UDCA.
Norwegian PBC patients (n = 182) (90% females; mean age 56.3 ± 8.9 years; Mayo risk score 4.38) who were included in a 5-year open-label study of UDCA therapy were subsequently followed up for up to 11.5 years. The lifetime survival was estimated using a Weibull survival model. The survival benefit from UDCA was based on a randomised clinical trial from Canada, comparing the effect of non-UDCA and UDCA. Survival and costs of standard care vs. standard care plus UDCA were simulated in a Markov model with death and liver transplantation as major events, invoking transition of a patient's state in the model.
The gain in life expectancy for a PBC patient on UDCA compared with standard care was 2.24 years (1.19 years discounted). The lifetime treatment costs were EUR 151,403 and EUR 157,741 (EUR 102,912 and EUR 115,031 discounted) for patients with and without UDCA respectively. A probabilistic sensitivity analysis indicated an 82% probability that UDCA entails both greater life expectancy and lower costs than standard care.
The results of this study indicate that UDCA therapy is a dominant strategy as it confers reduced morbidity and mortality, as well as cost savings, compared with standard therapy.
PubMed ID
23915021 View in PubMed
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98 records – page 1 of 10.