Maciej Szymczak

Dr. Maciej Szymczak

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Research Focus & Metrics

Academic Career Length

17Years (2010-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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3 May 2021 in Journal of the American Society of Nephrology
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Journal Article
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CRChava L. Ramspek
Chava L. Ramspek
MEMarie Evans
Marie Evans
CWChristoph Wanner
Christoph Wanner
CDChristiane Drechsler
Christiane Drechsler
NCNicholas C. Chesnaye
Nicholas C. Chesnaye
TIthe EQUAL Study Investigators
the EQUAL Study Investigators
Significance Statement: Most kidney failure prediction models have been developed and validated in cohorts of patients with a wide range of disease severity, without accounting for the competing risk of death. Models recommended by guidelines, currently used in the clinic, have not undergone a head-to-head comparison. This study provides a comprehensive external validation of kidney failure prediction tools in two cohorts of patients with advanced CKD, taking the competing risk of death into account. Models that predict over a longer time frame of 5 years overestimate risk due to the competing risk of death. In patients with advanced CKD, the eight-variable 2-year Kidney Failure Risk Equation is recommended for short-term predictions surrounding preparation for RRT. The 4-year Grams model, which accounts for competing risk, is most suitable for longer-term predictions. Background: Various prediction models have been developed to predict the risk of kidney failure in patients with CKD. However, guideline-recommended models have yet to be compared head to head, their validation in patients with advanced CKD is lacking, and most do not account for competing risks. Methods: To externally validate 11 existing models of kidney failure, taking the competing risk of death into account, we included patients with advanced CKD from two large cohorts: the European Quality Study (EQUAL), an ongoing European prospective, multicenter cohort study of older patients with advanced CKD, and the Swedish Renal Registry (SRR), an ongoing registry of nephrology-referred patients with CKD in Sweden. The outcome of the models was kidney failure (defined as RRT-treated ESKD). We assessed model performance with discrimination and calibration. Results: The study included 1580 patients from EQUAL and 13,489 patients from SRR. The average c statistic over the 11 validated models was 0.74 in EQUAL and 0.80 in SRR, compared with 0.89 in previous validations. Most models with longer prediction horizons overestimated the risk of kidney failure considerably. The 5-year Kidney Failure Risk Equation (KFRE) overpredicted risk by 10%–18%. The four- and eight-variable 2-year KFRE and the 4-year Grams model showed excellent calibration and good discrimination in both cohorts. Conclusions: Some existing models can accurately predict kidney failure in patients with advanced CKD. KFRE performed well for a shorter time frame (2 years), despite not accounting for competing events. Models predicting over a longer time frame (5 years) overestimated risk because of the competing risk of death. The Grams model, which accounts for the latter, is suitable for longer-term predictions (4 years).

1 December 2022 in Clinical Journal of the American Society of Nephrology
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Journal Article
Closed access
EREsther N.M. de Rooij
Esther N.M. de Rooij
YMY. Meuleman
Y. Meuleman
JFJohan W. de Fijter
Johan W. de Fijter
KJKitty J. Jager
Kitty J. Jager
NCNicholas C. Chesnaye
Nicholas C. Chesnaye
Ellen Karen HoogeveenEllen Karen Hoogeveen
Ellen Karen Hoogeveen
Background and objectives: For older patients with kidney failure, lowering symptom burden may be more important than prolonging life. Dialysis initiation may affect individual kidney failure–related symptoms differently, but the change in symptoms before and after start of dialysis has not been studied. Therefore, we investigated the course of total and individual symptom number and burden before and after starting dialysis in older patients. Design, setting, participants, & measurements: The European Quality (EQUAL) study is an ongoing, prospective, multicenter study in patients ≥65 years with an incident eGFR ≤20 ml/min per 1.73 m2. Using the dialysis symptom index (DSI), 30 symptoms were assessed every 3–6 months between 2012 and 2021. Scores for symptom number range from zero to 30 and, for burden, from zero to 150, with higher scores indicating more severity. Using mixed effects models, we studied symptoms during the year preceding and the year after dialysis initiation. Results: We included 456 incident patients on dialysis who filled out at least one DSI during the year before or after dialysis. At dialysis initiation, mean (SD) participant age was 76 (6) years, 75% were men, mean (SD) eGFR was 8 (3) ml/min per 1.73 m2, 44% had diabetes, and 46% had cardiovascular disease. In the year before dialysis initiation, symptom number increased +3.6 (95% confidence interval [95% CI], +2.5 to +4.6) and symptom burden increased +13.3 (95% CI, +9.5 to +17.0). In the year after, symptom number changed −0.9 (95% CI, −3.4 to +1.5) and burden decreased −5.9 (95% CI, −14.9 to −3.0). At dialysis initiation, “fatigue,” “decreased interest in sex,” and “difficulty becoming sexually aroused” had the highest prevalence of 81%, 69%, and 68%, respectively, with a burden of 2.7, 2.4, and 2.3, respectively. “Fatigue” somewhat improved after dialysis initiation, whereas the prevalence and burden of sexual symptoms further increased. Conclusions: Symptom burden worsened considerably before and stabilized after dialysis initiation. “Fatigue,” “decreased interest in sex,” and “difficulty becoming sexually aroused” were considered most burdensome, of which only “fatigue” somewhat improved after dialysis initiation.

1 August 2022 in Clinical Journal of the American Society of Nephrology
Verified
Journal Article
Closed access
EREsther N.M. de Rooij
Esther N.M. de Rooij
YMY. Meuleman
Y. Meuleman
JFJohan W. de Fijter
Johan W. de Fijter
SCSaskia Le Cessie
Saskia Le Cessie
KJKitty J. Jager
Kitty J. Jager
Ellen Karen HoogeveenEllen Karen Hoogeveen
Ellen Karen Hoogeveen
Background and objectives: In older people with kidney failure, improving health-related quality of life is often more important than solely prolonging life. However, little is known about the effect of dialysis initiation on health-related quality of life in older patients. Therefore, we investigated the evolution of health-related quality of life before and after starting dialysis in older patients with kidney failure. Design, setting, participants, & measurements: The European Quality study is an ongoing prospective, multicenter study in patients aged ≥65 years with an incident eGFR ≤20 ml/min per 1.73 m2. Between April 2012 and December 2021, health-related quality of life was assessed every 3–6 months using the 36-item Short-Form Health Survey (SF-36), providing a mental component summary (MCS) and a physical component summary (PCS). Scores range from zero to 100, with higher scores indicating better health-related quality of life. With linear mixed models, we explored the course of health-related quality of life during the year preceding and following dialysis initiation. Results: In total, 457 patients starting dialysis were included who filled out at least one SF-36 during follow-up. At dialysis initiation, mean ± SD age was 76±6 years, eGFR was 8±3 ml/min per 1.73 m2, 75% were men, 9% smoked, 45% had diabetes, and 46% had cardiovascular disease. Median (interquartile range) MCS was 53 (38–73), and median PCS was 39 (27–58). During the year preceding dialysis, estimated mean change in MCS was −13 (95% confidence interval, −17 to −9), and in PCS, it was −11 (95% confidence interval, −15 to −7). In the year following dialysis, estimated mean change in MCS was +2 (95% confidence interval, −7 to +11), and in PCS, it was −2 (95% confidence interval, −11 to +7). Health-related quality-of-life patterns were similar for most mental (mental health, role emotional, social functioning, vitality) and physical domains (physical functioning, bodily pain, role physical). Conclusions: Patients experienced a clinically relevant decline of both mental and physical health-related quality of life before dialysis initiation, which stabilized thereafter. These results may help inform older patients with kidney failure who decided to start dialysis.

5 January 2010 in Archivum Immunologiae et Therapiae Experimentalis
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Journal Article
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MSMaciej Szymczak
Maciej Szymczak
JKJakub Kuźniar
Jakub Kuźniar
MKMarian Klinger
Marian Klinger
The glomerular basement membrane (GBM) is a kind of net that remains in a state of dynamic equilibrium. Heparan sulfate proteoglycans (HSPGs) are among its most important components. There are much data indicating the significance of these proteoglycans in protecting proteins such as albumins from penetrating to the urine, although some new data indicate that loss of proteoglycans does not always lead to proteinuria. Heparanase is an enzyme which cleaves β 1,4 d-glucuronic bonds in sugar groups of HSPGs. Thus it is supposed that heparanase may have an important role in the pathogenesis of proteinuria. Increased heparanase expression and activity in the course of many glomerular diseases was observed. The most widely documented is the significance of heparanase in the pathogenesis of diabetic nephropathy. Moreover, heparanase acts as a signaling molecule and may influence the concentrations of active growth factors in the GBM. It is being investigated whether heparanase inhibition may cause decreased proteinuria. The heparanase inhibitor PI-88 (phosphomannopentaose sulfate) was effective as an antiproteinuric drug in an experimental model of membranous nephropathy. Nevertheless, this drug is burdened by some toxicity, so further investigations should be considered.

1 February 2022 in Clinical Journal of the American Society of Nephrology
Verified
Journal Article
Closed access
PDF file
NCNicholas C. Chesnaye
Nicholas C. Chesnaye
YMY. Meuleman
Y. Meuleman
EREsther N.M. de Rooij
Esther N.M. de Rooij
Ellen Karen HoogeveenEllen Karen Hoogeveen
Ellen Karen Hoogeveen
FDFriedo W. Dekker
Friedo W. Dekker
TIthe EQUAL Study Investigators
the EQUAL Study Investigators
Background and objectives: The effect of sex on longitudinal health-related quality of life remains unknown in CKD. Here we assess differences in the sex-specific evolution of health-related quality of life in older men and women with advanced CKD. Design, setting, participants, & measurements: The European Quality Study on Treatment in Advanced Chronic Kidney Disease is a European observational prospective cohort study in referred patients with CKD and an incident eGFR<20 ml/min per 1.73 m2 who are ≥65 years of age not on dialysis. Health-related quality of life was measured using the 36-Item Short Form Survey at 3- to 6-month intervals between April 2012 and September 2020, providing Physical Component Summary and Mental Component Summary scores. Trajectories were modeled by sex using linear mixed models, and sex differences in health-related quality-of-life slope were explored. Results: We included 5345 health-related quality-of-life measurements in 1421 participants. At baseline, women had considerably lower mean Physical Component Summary (42) and Mental Component Summary (60) compared with men (Physical Component Summary: 55; Mental Component Summary: 69; P<0.001). However, during follow-up, Physical Component Summary and Mental Component Summary scores declined approximately twice as fast in men (Physical Component Summary: 2.5 per year; 95% confidence interval, 1.8 to 3.1; Mental Component Summary: 2.7 per year; 95% confidence interval, 2.0 to 3.4) compared with in women (Physical Component Summary: 1.1 per year; 95% confidence interval, 0.1 to 2.0; Mental Component Summary: 1.6 per year; 95% confidence interval, 0.7 to 2.6). This difference was partly attenuated after adjusting for important covariates, notably eGFR decline. Higher serum phosphate, lower hemoglobin, and the presence of preexisting diabetes were associated with lower Physical Component Summary and Mental Component Summary scores in men but to a lesser extent in women. Conclusions: Among older men and women with advanced CKD, women had lower health-related quality of life at baseline, but men experienced a more rapid decline in health-related quality of life over time.

18 April 2016 in Archivum Immunologiae et Therapiae Experimentalis
Verified
Journal Article
Open access
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MSMaciej Szymczak
Maciej Szymczak
JKJakub Kuźniar
Jakub Kuźniar
WKWacław Kopeć
Wacław Kopeć
MŻMarcelina Żabińska
Marcelina Żabińska
ZMZofia Marchewka
Zofia Marchewka
MKMarian Klinger
Marian Klinger
Heparanase is a β-glucuronidase that cleaves sugar chains of heparan sulfate proteoglycans. It is believed that heparanase may be involved in the pathogenesis of proteinuria. The aim of this study was to assess the significance of heparanase in the pathogenesis of particular glomerulonephritis types. The evaluation of heparanase activity in serum, urine, and granulocytes and superoxide dismutase (SOD) activity in granulocytes of patients with lupus nephritis (n = 17), membranous nephropathy (n = 11), IgA nephropathy (n = 12), focal and segmental glomerulosclerosis (n = 18), mesangiocapillary glomerulonephritis (n = 12) and in 19 healthy volunteers were performed. The heparanase activity in granulocytes of patients with lupus nephritis and membranous nephropathy was higher than heparanase activity in granulocytes in the control group (p = 0.02 in both cases). This is the first observation of this phenomenon. There was no difference between SOD activity in granulocytes of patients with all assessed types of glomerulonephritis and the control group. A positive correlation between heparanase activity in urine and double-strain DNA antibodies (r = 0.51; p = 0.04), and reverse correlations between heparanase in urine and hemolytic activity of the complement (r = −0.57; p = 0.03) in the lupus nephritis group, and between heparanase activity in granulocytes and serum total protein level (r = −0.69; p = 0.02) in membranous nephropathy were observed. Increase in heparanase activity without changes in superoxide dismutase activity in the granulocytes from patients with lupus nephritis and membranous nephropathy was observed. It may be used as one of the markers of these disease activities.