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    <title>Liem, Y.S.</title>
    <link>http://repub.eur.nl/res/aut/7856/</link>
    <description>List of Publications</description>
    <language>en</language>
    <image>
      <url>http://repub.eur.nl/static-eur/img/logo.png</url>
      <title>RePub, Erasmus University Rotterdam</title>
      <link>http://repub.eur.nl</link>
    </image>
    <item>
      <title>Quantifying the benefit of early living-donor renal transplantation with a simulation model of the Dutch renal replacement therapy population (Article)</title>
      <link>http://repub.eur.nl/res/pub/34735/</link>
      <pubDate>2012-01-01T00:00:00Z</pubDate>
      <description>Background.Early living-donor transplantation improves patient-and graft-survival compared with possible cadaveric renal transplantation (RTx), but the magnitude of the survival gain is unknown. For patients starting renal replacement therapy (RRT), we aimed to quantify the survival benefit of early living-donor transplantation compared with dialysis and possible cadaveric transplantation and to estimate the population benefit from increasing the early transplantation rate. Methods.We used a decision-analytic computer-simulation model, with a lifetime time horizon, simulating patients starting RRT, using data from the Dutch End-Stage Renal Disease Registry and published data. We compared the (quality adjusted) life expectancy (LE) of 'early living-donor RTx' and 'dialysis' (with possible cadaveric RTx if available). Results.LE and quality-adjusted LE benefits of the early living-donor RTx compared with the dialysis strategy for 40-year-old patients ranged from 7.5 to 9.9 life years (LYs) [6.7-8.8 quality-adjusted life years (QALYs)] depending on the primary renal disease. For 70-year-old patients, the benefit was 4.3-6.0 LYs (4.3-6.0 QALYs). Increasing the early transplantation rate from currently 5.8 to 22.2% (the highest in Europe) would increase average LE by 1.2 LYs and total LE for annual incident cases in the Netherlands by &gt;1800 LYs. Conclusions.Efforts to increase early living-donor RTx could potentially substantially increase LE for patients starting RRT, especially in younger patients. </description>
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      <title>Propensity scores in the presence of effect modification: A case study using the comparison of mortality on hemodialysis versus peritoneal dialysis (Article)</title>
      <link>http://repub.eur.nl/res/pub/28650/</link>
      <pubDate>2010-05-13T00:00:00Z</pubDate>
      <description>Purpose. To control for confounding bias from non-random treatment assignment in observational data, both traditional multivariable models and more recently propensity score approaches have been applied. Our aim was to compare a propensity score-stratified model with a traditional multivariable-adjusted model, specifically in estimating survival of hemodialysis (HD) versus peritoneal dialysis (PD) patients. Methods. Using the Dutch End-Stage Renal Disease Registry, we constructed a propensity score, predicting PD assignment from age, gender, primary renal disease, center of dialysis, and year of first renal replacement therapy. We developed two Cox proportional hazards regression models to estimate survival on PD relative to HD, a propensity score-stratified model stratifying on the propensity score and a multivariable-adjusted model, and tested several interaction terms in both models. Results. The propensity score performed well: it showed a reasonable fit, had a good c-statistic, calibrated well and balanced the covariates. The main-effects multivariable-adjusted model and the propensity score-stratified univariable Cox model resulted in similar relative mortality risk estimates of PD compared with HD (0.99 and 0.97, respectively) with fewer significant covariates in the propensity model. After introducing the missing interaction variables for effect modification in both models, the mortality risk estimates for both main effects and interactions remained comparable, but the propensity score model had nearly as many covariates because of the additional interaction variables. Conclusion. Although the propensity score performed well, it did not alter the treatment effect in the outcome model and lost its advantage of parsimony in the presence of effect modification. </description>
    </item> <item>
      <title>Complex regional pain syndrome type 1 may be associated with menstrual cycle disorders: A case-control study (Article)</title>
      <link>http://repub.eur.nl/res/pub/24312/</link>
      <pubDate>2009-10-01T00:00:00Z</pubDate>
      <description>Background: Complex regional pain syndrome type 1 (CRPS1) can develop after severe trauma or surgery in the limbs, and presents with chronic, changes in temperature, edema and dysfunction. Seventy-five percent of CRPS1 patients are female. While neurological and inflammatory components have been proposed, the etiology remains unclear. No consensus on optimal management of CRPS1 exists. In traditional Chinese medicine, menstrual disorders are related to the state of women's constitution and therefore identify their pain patterns. A classification by constitution might improve the pain management in CRPS1 patients. It is unknown whether associations exist between menstrual-cycle-conditions and CRPS1. Aim: To investigate whether a specified menstrual condition is associated with the risk of developing CRPS1. Methods: A population-based case-control study of CRPS1 was conducted among Dutch women aged 18-82; i.e. 34 women with CRPS1 and 147 controls. A standard questionnaire consisting of 59 menstrual-cycle-symptom-based questions was administered. From this questionnaire, 15 CRPS1-related questions (DRQ 15) were analyzed. We used multivariate logistic regression to obtain odds ratios and 95% confidence intervals (CI) for specified menstrual disorders adjusting for age, oral contraceptives, hysterectomy and age at menarche ≤12 and ≥17 years. Results: On the basis of the DRQ 15, women with CRPS1 were 5.3 (95%CI 2.1, 12.9) times more likely to have menstrual disorders than comparable controls. Conclusion: Our results suggest that selected menstrual conditions are associated with the risk of developing CRPS1. </description>
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      <title>Early living-donor kidney transplantation: A review of the associated survival benefit (Article)</title>
      <link>http://repub.eur.nl/res/pub/27156/</link>
      <pubDate>2009-02-15T00:00:00Z</pubDate>
      <description>Avoidance of dialysis-related morbidity, improvement in quality of life, and reduction of costs have been mentioned as advantages of preemptive kidney transplantation. However, this therapeutic option is underutilized. Previous studies assessing the patient survival benefit of preemptive kidney transplantation compared it with postdialysis kidney transplantation. These studies may have been subjected to lead-time bias. When comparing patient survival of preemptive kidney transplant patients with waitlisted dialysis patients, there is a clear patient survival advantage in favor of preemptive kidney transplantation. This benefit justifies encouragement of preemptive kidney transplantation. </description>
    </item> <item>
      <title>Retrograde catheterization of haemodialysis fistulae and grafts: Angiographic depiction of the entire vascular access tree and stenosis treatment (Article)</title>
      <link>http://repub.eur.nl/res/pub/14963/</link>
      <pubDate>2009-02-01T00:00:00Z</pubDate>
      <description>Background. The European Best Practice Guidelines on Vascular Access propose magnetic resonance angiography (MRA) of dysfunctional dialysis fistulae and grafts if visualization of the complete arterial inflow and outflow vessels is needed. In a prospective multi-centre study we determined the technical success rate of complete vascular access tree depiction by digital subtraction angiography (DSA) as an alternative to MRA. Instead of a more invasive brachial artery of femoral artery approach, we performed a retrograde catheterization of the venous outflow or graft, and stenoses were treated in connection with DSA. Methods. A catheter was advanced into the central arterial inflow after retrograde puncture of the venous outflow or graft for depiction of the complete inflow, access region and complete outflow. Access DSA through femoral artery puncture was done if the retrograde approach failed to depict the complete vascular access tree. Stenoses with a luminal diameter reduction ≥50% were treated, if possible, in connection with DSA. Results. A total of 116 dysfunctional haemodialysis fistulae and 50 grafts were included. Retrograde DSA depicted the complete vascular tree in 162 patients (97.6%). The arteriovenous anastomosis of four fistulae could not be negotiated by a catheter. DSA demonstrated 247 significant stenoses: 30, 128 and 89 were located in the arterial inflow (12.1%), AV anastomosis and graft region (51.8%) and venous outflow (36.0%), respectively. Ten patients (6.0%) had no stenosis. Eight (4.8%), 55 (33.1%) and 33 (19.9%) patients demonstrated stenoses in only inflow, access region or outflow, respectively. Stenoses in two or three vascular territories were present in 53 (31.9%) and 7 (4.2%) patients, respectively. A technically successful endovascular intervention was obtained in 135 of the 139 patients (97.1%) who underwent angioplasty and/or stent placement. Additional sheath insertion by antegrade outflow puncture was needed in 46 patients (33.1%) for the treatment of coexisting venous outflow stenoses, located downstream from the retrograde positioned sheath. Two minor complications were observed at DSA/angioplasty. Conclusion. As an alternative to MRA, full retrograde DSA is safe and effective for stenosis detection and stenosis treatment. However, access evaluation by a non-invasive imaging modality such as colour duplex ultrasound will be sufficient in most cases as proximal inflow stenoses are encountered in a minority of patients. Full retrograde DSA, including complete arterial inflow depiction, may then be reserved for cases with an unsuccessful outcome following endovascular intervention of stenoses depicted at ultrasound.</description>
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      <title>Preference-based quality of life of patients on renal replacement therapy: A systematic review and meta-analysis (Article)</title>
      <link>http://repub.eur.nl/res/pub/30198/</link>
      <pubDate>2008-07-01T00:00:00Z</pubDate>
      <description>Objectives: Various utility measures have been used to assess preference-based quality of life of patients with end-stage renal disease (ESRD). The purposes of this study were to summarize the literature on utilities of hemodialysis (HD), peritoneal dialysis (PD), and renal transplantation (RTx) patients, to compare utilities between these patient groups, and to obtain estimates for quality-of-life adjustment in economic analyses. Methods: We searched the English literature for studies that reported visual analog scale (VAS), time trade-off (TTO), standard gamble (SG), EuroQol-5D (EQ-5D), and health utilities index (HUI) values of ESRD patients. We extracted patient characteristics and utilities and calculated mean utilities and 95% confidence intervals (CIs) for categories defined by utility measure and treatment modality using random-effects models. Results: We identified 27 articles that met the inclusion criteria. VAS articles were too heterogeneous to summarize quantitatively and we found only one study reporting HUI values. Thus, we summarized utilities from TTO, SG, and EQ-5D studies. Mean TTO and EQ-5D-index values were lower for dialysis compared to RTx patients, though not statistically significant for TTO values (TTO values: HD 0.61, 95% CI 0.54-0.68; PD 0.73, 95% CI 0.61-0.85; RTx 0.78, 95% CI 0.63-0.93; EQ-5D-index values: HD 0.56, 95% CI 0.49-0.62; PD 0.58, 95% CI 0.50-0.67; RTx 0.81, 95% CI 0.72-0.90). Mean HD versus PD associated TTO, EQ-5D-index and EQ-VAS values were not statistically significantly different. Conclusion: RTx patients tended to have a higher utility than dialysis patients. Among HD and PD patients, there were no statistically significant differences in utility. </description>
    </item> <item>
      <title>Modeling Outcome of Patients on Renal Replacement Therapy (Doctoral Thesis)</title>
      <link>http://repub.eur.nl/res/pub/12621/</link>
      <pubDate>2008-06-18T00:00:00Z</pubDate>
      <description>The incidence of end-stage renal disease is increasing and therefore, the number of
patients requiring renal replacement therapy (RRT), renal dialysis or renal transplantation
(RTx), has been rising. The various forms of RRT are associated with differences
in survival and quality of life. Knowledge of long-term outcomes of these patients is
imperative to the optimal implementation of treatment modalities and care for this
patient population.</description>
    </item> <item>
      <title>Using heparin therapy to reverse protein-losing enteropathy in a patient with CDG-Ib (Article)</title>
      <link>http://repub.eur.nl/res/pub/30504/</link>
      <pubDate>2008-04-01T00:00:00Z</pubDate>
      <description>Background: A 22-year-old female presented with edema, diarrhea, hypoalbuminemia and pancytopenia. She had previously been diagnosed with congenital disorder of glycosylation type Ib, and had a history of congenital hepatic fibrosis, portal hypertension and esophageal varices. In the past she had refused mannose therapy because of associated diarrhea and abdominal pain. Investigations: Laboratory examinations, abdominal ultrasonography, bacterial and viral cultures of blood, urine and stools, double-balloon enteroscopy and fecal excretion test using51Cr-labeled albumin. Diagnosis: Protein-losing enteropathy. Management: Infusion of albumin followed by intravenous and subcutaneous therapy with unfractionated heparin.</description>
    </item> <item>
      <title>Quality of life assessed with the medical outcomes study short form 36-item health survey of patients on renal replacement therapy: A systematic review and meta-analysis (Article)</title>
      <link>http://repub.eur.nl/res/pub/11579/</link>
      <pubDate>2007-09-01T00:00:00Z</pubDate>
      <description>Objectives: The Medical Outcomes Study Short Form
36-Item Health Survey (SF-36) is the most widely used
generic instrument to estimate quality of life of patients on
renal replacement therapy. Purpose of this study was to summarize
and compare the published literature on quality of life
of hemodialysis (HD), peritoneal dialysis (PD), and renal
transplant (RTx) patients.
Methods: We used random-effects regression analyses to
compare the SF-36 scores across treatment groups and
adjusted this comparison for age and prevalence of diabetes
using random-effects meta-regression analyses.
Results: We found 52 articles that met the inclusion criteria,
reporting quality of life of 36,582 patients. The unadjusted
scores of all SF-36 health dimensions were not significantly
different between HD and PD patients, but the scores of RTx
patients were higher than those of dialysis patients, except for
the dimensions Mental Health and Bodily Pain. Point differences
between dialysis and RTx patients varied from 2 to 32.
With adjustment for age and diabetes, the differences became
smaller (point difference 2–22). The significance of the differences
of both dialysis groups compared with RTx recipients
disappeared for the dimensions Vitality and Social
Functioning. The significance of the differences between HD
and RTx patients disappeared on the dimensions Physical
Functioning, Role Physical, and Bodily Pain.
Conclusion: We conclude that dialysis patients have a lower
quality of life than RTx patients, but this difference can
partly be explained by differences in age and prevalence of
diabetes.
Keywords: hemodialysis, meta-analysis, peritoneal dialysis,
quality of life, renal transplantation.</description>
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      <title>Comparison of hemodialysis and peritoneal dialysis survival in The Netherlands (Article)</title>
      <link>http://repub.eur.nl/res/pub/35652/</link>
      <pubDate>2007-01-01T00:00:00Z</pubDate>
      <description>Considerable geographic variation exists in the relative use of hemodialysis (HD) vs peritoneal dialysis (PD). Studies comparing survival between these modalities have yielded conflicting results. Our aim was to compare the survival of Dutch HD and PD patients. We developed Cox regression models using 16 643 patients from the Dutch End-Stage Renal Disease Registry (RENINE) adjusting for age, gender, primary renal disease, center of dialysis, year of start of renal replacement therapy, and included several interaction terms. We assumed definite treatment assignment at day 91 and performed an intention-to-treat analysis, censoring for transplantation. To account for time dependency, we stratified the analysis into three time periods, &gt;3-6, &gt;6-15, and &gt;15 months. For the first period, the mortality hazard ratio (HR) of PD compared with HD patients was 0.26 (95% confidence interval (CI) 0.17-0.41) for 40-year-old non-diabetics, which increased with age and presence of diabetes to 0.95 (95% CI 0.64-1.39) for 70-year-old patients with diabetes as primary renal disease. The HRs of the second period were generally higher. After 15 months, the HR was 0.86 (95% CI 0.74-1.00) for 40-year-old non-diabetics and 1.42 (95% CI 1.23-1.65) for 70-year-old patients with diabetes as primary renal disease. We conclude that the survival advantage for Dutch PD compared with HD patients decreases over time, with age and in the presence of diabetes as primary disease. </description>
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      <title>Living renal donors: optimizing the imaging strategy--decision- and cost-effectiveness analysis (Article)</title>
      <link>http://repub.eur.nl/res/pub/10042/</link>
      <pubDate>2003-01-01T00:00:00Z</pubDate>
      <description>PURPOSE: To determine the most cost-effective strategy for preoperative
      imaging performed in potential living renal donors. MATERIALS AND METHODS:
      In a decision-analytic model, the societal cost-effectiveness of digital
      subtraction angiography (DSA), gadolinium-enhanced magnetic resonance (MR)
      angiography, contrast material-enhanced spiral computed tomographic (CT)
      angiography, and combinations of these imaging techniques was evaluated.
      Outcome measures included lifetime cost, quality-adjusted life-years
      (QALYs), and incremental cost-effectiveness ratios. A base-case analysis
      was performed with a 40-year-old female donor and a 40-year-old female
      recipient. RESULTS: For the donor, MR angiography (24.05 QALYs and 9,000
      dollars) dominated all strategies except for MR angiography with CT
      angiography, which had an incremental ratio of 245,000 dollars per QALY.
      For the recipient, DSA and DSA with MR angiography yielded similar results
      (10.46 QALYs and 179,000 dollars) and dominated all other strategies. When
      results for donor and recipient were combined, DSA dominated all other
      strategies (34.51 QALYs and 188,000 dollars). If DSA was associated with a
      99% specificity or less for detection of renal disease, MR angiography
      with CT angiography was superior (34.47 QALYs and 190,000 dollars).
      CONCLUSION: For preoperative imaging in a potential renal donor, DSA is
      the most cost-effective strategy if it has a specificity greater than 99%
      for detection of renal disease; otherwise, MR angiography with CT
      angiography is the most cost-effective strategy.</description>
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