Heikki Saha

Tampere University Hospital (TAUH), Tammerfors, Pirkanmaa, Finland

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Publications (63)282.4 Total impact

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    ABSTRACT: The annual number of kidney transplantations in Finland is 150 to 200. Successful kidney transplantation improves the patient's quality of life and prognosis and is cost-effective as compared with dialytic therapy. Only a few per cent of transplantations are made from a living donor. Waiting times for kidney transplantations have become longer in the last few years. Whereas attempts should be made to better identify potential brain-dead organ donors in order to increase kidney transplantations, transplantations from living donors could also reduce the disproportion between the availability and the need of organs.
    No preview · Article · Nov 2013 · Duodecim; lääketieteellinen aikakauskirja
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    ABSTRACT: Background/aims: Chronic kidney disease (CKD) patients on dialysis are prone to vitamin D insufficiency despite oral vitamin D supplementation. Here, we studied whether narrow-band ultraviolet B (NB-UVB) exposures improve vitamin D balance. Methods: 14 haemodialysis patients and 15 healthy subjects receiving oral cholecalciferol 20 µg daily got nine NB-UVB exposures on the entire body. Serum 25-hydroxyvitamin D (25(OH)D) was measured by radioimmunoassay. Cutaneous mRNA expression levels of CYP27A1 and CYP27B1, two enzymes required for hydroxylation of vitamin D into its active metabolite, were also measured. Results: The baseline serum 25(OH)D concentration was 57.6 ± 18.2 nmol/l in the CKD patients and 74.3 ± 14.8 nmol/l in the healthy subjects. The NB-UVB course increased serum 25(OH)D by 14.0 nmol/l (95% CI 8.7-19.5) and 17.0 nmol/l (CI 13.7-20.2), respectively. At baseline the CKD patients showed significantly increased CYP27B1 levels compared to the healthy subjects. Conclusions: A short NB-UVB course is an efficient way to improve vitamin D balance in CKD patients on dialysis who are receiving oral vitamin D supplementation. The increased cutaneous CYP27B1 levels in the CKD patients suggest that the loss of renal activity of this enzyme is at least partially compensated for by the skin.
    No preview · Article · Sep 2013 · Nephron Clinical Practice
  • Tapani E Salonen · Heikki Saha
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    ABSTRACT: Data about outcomes and costs for peritoneal catheter insertion on an outpatient basis are scarce. Using patient files, all peritoneal dialysis (PD) catheter insertions performed between 2004 and 2009 in a single-center tertiary care institution for adult patients were located. Patient demographics, complications, hospitalizations, survival, and treatment modality changes were recorded. Procedure-related expenses were valued as actual production costs. During the study period, 106 PD catheters were inserted. In 46 cases, the patients were admitted electively for catheter insertion; 19 catheters were placed during admission for other medical reasons; and 41 catheters were placed on an outpatient basis. Among the study patients (54.7 ± 16.0 years of age), 45% were diabetic. Early (<30 days) catheter-related complications occurred in 22% of patients. The incidences of technique failure and any complication within 90 days were 10% and 38% respectively. The occurrence of complications was not statistically significantly different for outpatients and electively admitted patients. Average costs for catheter insertion were higher in electively hospitalized patients than in outpatients (€2320± €960 vs €1346 ± €208, p < 0.000). Compared with an inpatient procedure, outpatient insertion of a PD catheter results in similar outcomes at a lower cost.
    No preview · Article · Jul 2013
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    ABSTRACT: Chronic kidney disease (CKD) patients are especially prone to vitamin D insufficiency. Narrow-band ultraviolet B (NB-UVB) treatment increases serum 25-hydroxyvitamin D [25(OH)D] in dermatological patients, and we studied whether it also improves vitamin D balance in CKD patients on haemodialysis. Fifteen dialysis patients (mean age 48.3 years) and 12 healthy subjects (mean age 43.6 years) received nine NB-UVB exposures on the upper body. Serum 25(OH)D and 1,25(OH)(2)D were measured before and after the exposures. From skin biopsy specimen messenger RNA (mRNA) expression levels of CYP24A1 and CYP27B1, two enzymes needed for hydroxylation of vitamin D into its active metabolites, and of antimicrobial peptide cathelicidin, were examined. Before NB-UVB, mean serum 25(OH)D was 32.5 ± 10.2 nmol/L in the dialysis patients and 60.2 ± 18.0 nmol/L in the healthy subjects (P < 0.001). After eight NB-UVB exposures, serum 25(OH)D increased by 13.8 nmol/L (43%; P < 0.001) and serum 1,25(OH)(2)D by 3.3 pmol/L (27%; P = 0.002) in the dialysis patients. After NB-UVB exposures, CYP27B1 mRNA was increased (P = 0.04), whereas cathelicidin mRNA was decreased (P < 0.0001) compared to non-treated healthy subjects. One and 2 months after NB-UVB exposure, serum 25(OH)D was still 10% higher than initially in the dialysis patients. The present study shows that a short course of NB-UVB exposure increases significantly serum 25(OH)D and 1,25(OH)(2)D in dialysis patients. The effect is, however, short lasting suggesting that the patients need cyclic NB-UVB exposure to maintain their improved vitamin D concentration.
    Full-text · Article · Dec 2011 · Nephrology Dialysis Transplantation
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    ABSTRACT: The pan-European ECHO observational study evaluated cinacalcet in adult dialysis patients with secondary hyperparathyroidism (SHPT) in "real-world" clinical practice. A sub-analysis compared data for 7 European countries/country clusters: Austria, CEE (Czech Republic and Slovakia), France, Italy, Netherlands, Nordics (Denmark, Finland, Norway, and Sweden), and the UK/Ireland. Data on serum intact parathyroid hormone (iPTH), phosphorous, calcium, as well as the usage of cinacalcet, active vitamin D analogues and phosphate binders were compared. 1,865 patients (mean age 58 years) were enrolled: median baseline iPTH levels ranged from 605 pg/ml in Austria to 954 pg/ml in the UK/Ireland. After ~1 year of cinacalcet, median iPTH reductions from baseline ranged from 38% in the UK/Ireland to 58% in the Netherlands. The proportion of patients achieving NKF/K-DOQITM iPTH targets (150 - 300 pg/ml) at Month 12 ranged from 14% in the UK/Ireland to 40% in CEE. In general, use of sevelamer decreased, while use of calcium-based phosphate binders increased, during cinacalcet treatment. Vitamin D changes were more variable. The iPTH level at which cinacalcet is initiated in clinical practice differs considerably among different countries: where cinacalcet was started at a lower iPTH level this resulted in better achievement of serum iPTH targets.
    Full-text · Article · Sep 2010 · Clinical nephrology
  • Ilkka Helanterä · Heikki Saha · Petri Koskinen
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    ABSTRACT: Although the results of kidney transplantation have improved markedly, the long-term survival of renal allografts is still a major challenge. The long-term exposure of recipients to chronic renal failure and chronic immunosuppression increases the burden of infections, cardiovascular diseases, malignancies, and renal bone disease. The prevention and adequate treatment of these complications have become increasingly important. During the first months after kidney transplantation patients are followed carefully with short intervals; in stable patients the follow-up frequency is reduced later. Most important laboratory tests in the follow-up include parameters of graft function and pharmacokinetic monitoring of the immunosuppressive drugs.
    No preview · Article · Jan 2010 · Duodecim; lääketieteellinen aikakauskirja
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    ABSTRACT: In the treatment of end-stage renal disease, kidney transplantation is the best and most cost-effective alternative with regard to both prognosis and quality of life. Problems arise from the disproportion between the number of available allografts and the patients waiting for the transplantation. There are few absolute contraindications to kidney transplantation. In the assessment of the eligibility for transplantation of patients on dialysis the most important factors include cardiovascular diseases, cancer diseases, other diseases affecting operability and life expectancy, age, excess weight and possible infections.
    No preview · Article · Jan 2010 · Duodecim; lääketieteellinen aikakauskirja
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    M T Saha · H Sievänen · M K Salo · S Tulokas · H H Saha
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    ABSTRACT: We measured bone mass and structure using pQCT and DXA in adolescents with Type 1 diabetes and compared the results with those of healthy peers. Our results showed that diabetes is associated with reduced bone mass and smaller bones. The diabetes-associated deficits seemed to concern male adolescents more than females. The aim of this study was to compare bone mass and structure between adolescents with type 1 diabetes and their healthy peers. Peripheral quantitative computed tomography (pQCT) at radius and tibia, and dual-energy X-ray absorptiometry (DXA) at lumbar spine and proximal femur were performed for 48 adolescents, 26 girls and 22 boys, with type 1 diabetes, and for healthy peers matched for age, sex, body height and weight, and pubertal maturity. Diabetes was associated with reduced bone mineral content (BMC) and smaller bone cross-sectional size. Diabetic boys seemed to be more affected than diabetic girls. Among the boys, the mean deficit in BMC of all measured skeletal sites was more than 10%, while among the girls it was less than 5%. In conclusion, type 1 diabetes is associated with reduced BMC and appears to affect bone cross-sectional size and cortical rigidity. The diabetes-related skeletal deficits seemed to concern male adolescents more than females. Whether diabetes-related deficits would contribute to an increased risk of fractures in adulthood or later in life remains to be confirmed.
    Full-text · Article · Aug 2009 · Osteoporosis International
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    ABSTRACT: Cardiovascular calcification is a common complication in patients with chronic kidney disease (CKD). The study aim was to identify the characteristics and risk factors of valvular calcification, and its relationship to atherosclerosis, in CKD. In this cross-sectional study, a total of 135 patients with CKD (mean age 52 +/- 11 years) included 58 pre-dialysis patients, 36 dialysis patients, and 41 renal transplant recipients. A control group of 58 subjects was also examined. The characteristics of valvular calcification were assessed using transthoracic echocardiography. The combined prevalences of mitral or aortic valve calcification were 31% in pre-dialysis patients, 50% in dialysis patients, 29% in renal transplant recipients, and 12% in controls (p = 0.001). The prevalences of mitral annular calcification were 17%, 31%, 27% and 2%, respectively (p = 0.001). In multivariate analysis, the risk factors for valvular calcification in CKD were age, duration of dialysis treatment and interleukin-6 level. Mitral annular calcification proved to be five-fold more common in diabetic patients than among non-diabetics. A close association between valvular calcification and patients with or without increased carotid intima-media thickness (44% versus 15%, p < 0.001), carotid plaque (77% versus 49%, p = 0.002), calcified carotid plaque (65% versus 26%, p = 0.001), coronary artery disease (40% versus 15%, p = 0.003) and peripheral arterial disease (46% versus 9%, p < 0.001) was found. Valvular calcification is common in CKD, and is closely associated with findings of intimal arterial disease. The presence of inflammation and the duration of dialysis treatment contribute to this complication. Diabetes is also a prominent risk factor for mitral annular calcification in CKD.
    Full-text · Article · Jul 2009 · The Journal of heart valve disease
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    ABSTRACT: The use and effectiveness of cinacalcet in 'real-world' clinical practice was investigated in a pan-European observational study in dialysis patients with secondary hyperparathyroidism (SHPT) of varying severity. Adult patients with chronic kidney disease on dialysis who had initiated cinacalcet treatment were enrolled. Data were collected 6 months before initiating cinacalcet, at baseline (initiation of cinacalcet) and up to 12 months after cinacalcet initiation. A total of 1865 patients [mean (SD) age 58 (15) years] were enrolled from 187 sites in 12 countries. Most patients had a dialysis vintage of > or =1 year (1-5 years, n = 833; >5 years, n = 748 versus <1 year, n = 265). The patients generally had severely uncontrolled intact parathyroid hormone (iPTH) serum levels (median 721 pg/ml) and elevated phosphorus (median 5.9 mg/dl) and calcium (median 9.6 mg/dl) at baseline, despite being prescribed conventional therapies. The proportions of patients achieving the recommended [NKF-K/DOQI(TM) (KDOQI(TM))] targets increased from baseline [4%, 39%, 40% and 46% for iPTH, phosphorus, calcium and calcium-phosphorus product (Ca x P), respectively] to Month 12 (28%, 48%, 51% and 68%, respectively). At Month 12, 18% of patients had achieved the combined target for iPTH + Ca x P compared with 2% at baseline. Most patients (65%) received <60 mg/day cinacalcet at Month 12. Vitamin D sterol use remained fairly stable throughout the study. There was a 13% decrease in prescribed sevelamer; use of calcium-based phosphate binders increased by 5.6%. There was no unexpected safety or tolerability concerns. This analysis of current European clinical practice shows that-consistent with findings from randomized controlled trials and retrospective observational studies-cinacalcet improves attainment of KDOQI bone metabolism targets in dialysis patients with various stages of SHPT.
    Full-text · Article · Apr 2009 · Nephrology Dialysis Transplantation
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    ABSTRACT: The calcimimetic cinacalcet (Mimpara/Sensipar) simultaneously lowers parathyroid hormone (PTH), phosphorus (P) and calcium (Ca) levels in patients with secondary hyperparathyroidism. The OPTIMA study demonstrated that cinacalcet and adjusted doses of vitamin D maximized control of these parameters. This post-hoc analysis of OPTIMA data assessed the impact of reducing or increasing the dose of concomitant vitamin D on PTH, P and Ca in patients receiving cinacalcet. Dialysis patients with mean baseline intact PTH (iPTH) 300-800 pg/ml (31.8-84.8 pM) received doses of cinacalcet titrated to achieve an iPTH of 150-300 pg/ml (15.9-31.8 pM). The dose of vitamin D could then be decreased to further reduce serum P or Ca, or increased/initiated to further decrease PTH levels if iPTH >300 pg/ml or to increase Ca if Ca <8.0 mg/dl (2.0 mM). Vitamin D dose was assessed for 345 patients during a 23-week period. A total of 91 and 129 patients had an increase or decrease in vitamin D dose, respectively. By study end, mean iPTH, P, and Ca were similar in both vitamin D groups, although there were differences in biochemical parameters between groups at the start of the study. There were statistically significant reductions from baseline to study end in iPTH and Ca in both groups (p < 0.001). Although P was significantly reduced by week 23 in the group in which vitamin D dose was decreased (p = 0.007), the reduction in P was less and did not achieve significance in the group in which vitamin D dose was increased (p = 0.71). After initiating cinacalcet, the dose of vitamin D can be adjusted to maximize reductions in PTH, P and Ca; however, vitamin D-induced decreases in PTH need to be balanced with the diminished response in P and Ca.
    Full-text · Article · Apr 2009 · Nephron Clinical Practice
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    ABSTRACT: Retroperitoneal fibrosis (RPF) is a rare fibroinflammatory disease that leads to hydronephrosis and renal failure. In a case-control study, we have recently shown that asbestos exposure was the most important risk factor for RPF in the Finnish population. The aim of this study was to evaluate the relation of asbestos exposure to radiologically confirmed lung and pleural fibrosis among patients with RPF. Chest high-resolution computed tomography (HRCT) was performed on 16 unexposed and 22 asbestos-exposed RPF patients and 18 asbestos-exposed controls. Parietal pleural plaques (PPP), diffuse pleural thickening (DPT) and parenchymal fibrosis were scored separately. Most of the asbestos-exposed RPF patients and half of the asbestos-exposed controls had bilateral PPP, but only a few had lung fibrosis. Minor bilateral plaques were detected in two of the unexposed RPF patients, and none had lung fibrosis. DPT was most frequent and thickest in the asbestos-exposed RPF-patients. In three asbestos-exposed patients with RPF we observed exceptionally large pleural masses that were located anteriorly in the pleural space and continued into the anterior mediastinum.Asbestos exposure was associated with DPT in comparisons between RPF patients and controls (case-control analysis) as well as among RPF patients (case-case analysis). The most distinctive feature of the asbestos-exposed RPF patients was a thick DPT. An asbestos-related pleural finding was common in the asbestos-exposed RPF patients, but only a few of these patients had parenchymal lung fibrosis. RPF without asbestos exposure was not associated with pleural or lung fibrosis. The findings suggest a shared etiology for RPF and pleural fibrosis and furthermore possibly a similar pathogenetic mechanisms.
    Full-text · Article · Dec 2008 · Orphanet Journal of Rare Diseases
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    ABSTRACT: We evaluated the effects of the bisphosphonate pamidronate on bone histomorphometry, structure and strength in male rats with uninephrectomy or with chronic renal disease induced by 5/6 nephrectomy. In rats with chronic renal disease the plasma urea, phosphate and parathyroid hormone levels were significantly increased compared to rats with a uninephroctomy and none of these parameters was affected by pamidronate treatment. In the femoral midshaft, chronic renal disease reduced cortical bone mineral density and content. No difference was observed in the breaking load of the femoral midshaft. In the distal femur, a high-turnover renal osteodystrophy was found but pamidronate suppressed this bone turnover and increased bone mineral content. Treatment had no effect on chronic disease-induced augmentation of osteoid volume or fibroblast surface. These studies show that in this model of stage 3 renal disease, pamidronate increased mineral content in the femoral midshaft and distal metaphysis primarily by adding bone to endocortical and trabecular surfaces but did not reduce osteitis fibrosa.
    Full-text · Article · Sep 2008 · Kidney International
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    ABSTRACT: Knowledge of the usefulness of cystatin C measurement in the detection of chronic kidney disease in patients with rheumatoid arthritis (RA) is scant. The purpose of this study was to evaluate the ability of plasma cystatin C- and creatinine-based methods to predict glomerular filtration rate (GFR) and classify chronic kidney disease in RA patients. The study population consisted of 64 RA patients aged 41-86 years. Comparisons were made between measured plasma creatinine, cystatin C, creatinine clearance and GFR estimated by the Cockcroft-Gault (CG) and the Modification of Diet in Renal Disease (MDRD) formulas. The plasma clearance of (51)Cr-EDTA served as a reference. The Pearson correlation coefficients between plasma clearance of (51)Cr-EDTA and the markers of GFR were calculated. The correlation coefficients were 0.800 for plasma creatinine, 0.863 for cystatin C, 0.866 and 0.904 for GFR values estimated by MDRD and CG and 0.922 for plasma creatinine clearance. Statistically significant differences were detected between the correlation coefficients of plasma creatinine and GFR estimated by CG (p = 0.0412) and plasma creatinine and creatinine clearance (p = 0.0099). Creatinine clearance and the MDRD and CG formulas proved to be better at identifying GFR <90 ml/min than plasma creatinine or cystatin C. We recommend using the CG formula or creatinine clearance for the estimation of the GFR of RA patients instead of solely creatinine or cystatin C in clinical work.
    No preview · Article · Apr 2008 · Nephron Clinical Practice
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    ABSTRACT: Cinacalcet, a novel calcimimetic, targets the calcium-sensing receptor to lower parathyroid hormone (PTH), calcium, and phosphorus levels in dialysis patients with secondary hyperparathyroidism (SHPT). This study compared the efficacy of a cinacalcet-based regimen with unrestricted conventional care (vitamin D and phosphate binders) for achieving the stringent National Kidney Foundation Kidney Disease Outcomes Quality Initiative (KDOQI) targets for dialysis patients. Study design: In this multicenter, open-label study, hemodialysis patients with poorly controlled SHPT were randomized to receive conventional care (n = 184) or a cinacalcet-based regimen (n = 368). Doses of cinacalcet, vitamin D sterols, and phosphate binders were adjusted during a 16-wk dose-optimization phase with the use of algorithms that allowed cinacalcet to be used with adjusted doses of vitamin D. The primary end point was the proportion of patients with mean intact PTH < or =300 pg/ml during a 7-wk efficacy assessment phase. A higher proportion of patients receiving the cinacalcet-based regimen versus conventional care achieved the targets for PTH (71% versus 22%, respectively; P < 0.001), Ca x P (77% versus 58%, respectively; P < 0.001), calcium (76% versus 33%, respectively; P < 0.001), phosphorus (63% versus 50%, respectively; P = 0.002), and PTH and Ca x P (59% versus 16%, respectively, P < 0.001), and allowed a 22% reduction in vitamin D dosage in patients receiving vitamin D at baseline. Achievement of targets was greatest in patients with less severe disease (intact PTH range, 300 to 500 pg/ml) and the cinacalcet dose required was lower in these patients (median = 30 mg/d). Compared with conventional therapy, a cinacalcet-based treatment algorithm increased achievement of KDOQI treatment targets in dialysis patients in whom conventional therapy was no longer effective in controlling this disease.
    Full-text · Article · Jan 2008 · Clinical Journal of the American Society of Nephrology
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    ABSTRACT: Calcium phosphate product (Ca x Pi) is a clinically relevant tool to estimate the cardiovascular risk of patients with renal failure. In reports, mostly total serum calcium has been used. As measurement of serum ionized calcium has some benefits and is being used increasingly, we estimated the respective levels of calcium phosphate product using both total (t-Ca x Pi) and ionized calcium (ion-Ca x Pi). Fifty-eight healthy individuals and 180 hemodialysis (HD) patients from 2 centers were studied. Diagnostic accuracies for corresponding values of the t-Ca x Pi and ion-Ca x Pi were calculated using a GraphROC program. Of HD patients, 64% had t-Ca x Pi <4.4 mmol(2)/L(2) regarded as a desirable goal, and 10% had values over 5.6 mmol(2)/L(2) associated with a high cardiovascular risk. Based on GraphROC analysis, t-Ca x Pi of 4.4 mmol(2)/L(2) corresponded to a value of 2.2 mmol(2)/L(2) of ion-Ca x Pi and, respectively, t-Ca x Pi of 5.6 mmol(2)/L(2) corresponded 2.8 mmol(2)/L(2) of ion-Ca x Pi. Owing to the good agreement between the results in the 2 centers, these values for risk levels can be used in both centers. When measurement of ionized calcium is used, Ca x Pi values of 2.2 and 2.8 mmol(2)/L(2) can be used instead of generally used values of 4.4 and 5.6 mmol(2)/L(2) with total calcium.
    No preview · Article · Oct 2007 · Hemodialysis International
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    ABSTRACT: In the present article, we review current knowledge of the epidemiology, diagnosis, and treatment of peripheral vascular disease in patients with end-stage renal disease. The main focus is placed on diabetic patients receiving peritoneal dialysis, but studies on patients receiving hemodialysis are also reviewed, because most reports involve this patient group, and the number of reports on peripheral vascular disease in PD patients alone is limited. Copyright © 2007 International Society for Peritoneal Dialysis. Printed in Canada. All rights reserved.
    No preview · Article · Jul 2007 · Peritoneal dialysis international: journal of the International Society for Peritoneal Dialysis
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    ABSTRACT: Secondary hyperparathyroidism, malnutrition and inflammation have been reported to associate with adverse outcomes in dialysis patients. However, little is known about the implications of these conditions for treatment costs. The cost data of all adult patients who had entered dialysis therapy at Tampere University Hospital between 1991 and 1996 and had remained on dialysis for at least 1 year were collected. results of measurements of parathyroid hormone (PTH), calcium, phosphorus, albumin and C-reactive protein (CRP) were obtained from the database of the hospital. Patients (n = 109), aged 57.0 +/- 14.9 years, included 57% men and 37% diabetics; 62% started on hemodialysis and 38% on peritoneal dialysis. Average daily costs were USD 161 (range 95-360). After controlling for patients' age, body mass index, gender, dialysis modality and primary renal disease, there was a positive correlation between average CRP and average costs and a negative correlation between albumin and costs. Correlations between mineral metabolism markers and costs were not found, but there was a trend towards lower cost among patients who achieved the Kidney Disease Outcomes Quality Initiative targets of calcium, phosphorus and PTH (USD 145 +/- 31) compared with those with nonoptimal levels (USD 165 +/- 48; p = 0.095). Costs of patients with at least one in-target PTH measurement were lower than costs of patients with constantly low PTH (USD 148 +/- 31 vs. 170 +/- 48; p = 0.01). Serum levels of albumin and CRP correlated with dialysis patients' treatment costs. Achieving the Kidney Disease Outcomes Quality Initiative targets may be associated with lower costs.
    No preview · Article · Feb 2007 · Nephron Clinical Practice
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    ABSTRACT: Disturbed calcium-phosphorus balance significantly contributes to uraemic changes in large arteries. We examined the influences of high-calcium and high-phosphate intake on small artery tone in experimental renal insufficiency. Sixty-five rats were assigned to 5/6 nephrectomy (NTX) or sham operation. After 15 week disease progression, NTX rats were given high-calcium (3%), high-phosphate (1.5%) or control diet (0.3% calcium, 0.5% phosphate) for 12 weeks. Then isolated segments of small mesenteric arteries were studied using wire and pressure myographs. Subtotal nephrectomy reduced creatinine clearance by 60% and increased parathyroid hormone (PTH) and phosphate 12-fold and 2.7-fold, respectively. High-phosphate intake further elevated PTH and phosphate (33-fold and 5.5-fold, respectively), while the calcium diet suppressed them (to 3.5 and 62% vs sham, respectively). Ventricular B-type natriuretic peptide synthesis was increased, and blood pressure was 27 and 18 mmHg higher in NTX rats on control and phosphate diet, respectively, than in calcium-fed rats. Vasorelaxation to acetylcholine was impaired by approximately 50% in uraemic rats, and was further deteriorated by high-phosphate intake, whereas the calcium diet improved endothelium-mediated relaxation via nitric oxide and potassium channels. Small arteries of all NTX groups featured eutrophic inward remodelling: wall-to-lumen ratio was increased 1.3-fold without change in cross-sectional area. High-phosphate intake had a detrimental influence on secondary hyperparathyroidism and vasodilatation, whereas high-calcium intake reduced blood pressure and PTH, alleviated volume overload and improved vasorelaxation in experimental renal insufficiency. Therefore, alterations in the calcium-phosphorus balance can significantly modulate small artery tone during impaired kidney function.
    Full-text · Article · Nov 2006 · Nephrology Dialysis Transplantation
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    ABSTRACT: Chronic renal insufficiency (CRI) results in phosphate retention and secondary hyperparathyroidism, the treatment of which is largely based on the use of calcium salts as phosphate binders. Advanced CRI causes bone fragility, but information about bone geometry and strength in moderate CRI is scarce. We assigned 39 8-week-old male Sprague-Dawley rats to sham-operation (Sham) or 5/6 nephrectomy (NTX). Four weeks later, the rats were randomized to 0.3% calcium (Sham, NTX) or 3.0% calcium diet (Sham + Calcium, NTX + Calcium). After 8 weeks, the animals were sacrificed, plasma samples collected, and femora excised for neck and midshaft analyses: dual-energy X-ray absorptiometry, peripheral quantitative computed tomography, and biomechanical testing. The NTX increased plasma urea and PTH 1.6-fold and 3.6-fold, respectively, whereas high calcium intake suppressed PTH to 30% of controls. Total femoral bone mineral content decreased (-6.3%) in the NTX group, while this deleterious effect was reversed by high calcium diet. In the site-specific analysis of the femoral neck, the volumetric bone density (-6.5%) was decreased in the NTX group but not NTX + Calcium group. However, in the nephrectomized rats, there was also a concomitant increase in the cross-sectional area (+15%), and, despite the decrease in bone density, the mechanical strength of the femoral neck was maintained. In the midshaft, NTX decreased cortical volumetric bone density (-1.2%), but similar to the femoral neck, no differences were found in the mechanical strength. In conclusion, a decrease in bone mass in moderate experimental CRI was associated with a concomitant increase in bone size, and maintenance of mechanical competence. Although high calcium diet suppressed plasma PTH to under normal physiological levels, it prevented the CRI-induced loss of bone mass without an adverse influence on bone strength.
    Full-text · Article · Sep 2006 · Bone

Publication Stats

2k Citations
282.40 Total Impact Points

Institutions

  • 2000-2013
    • Tampere University Hospital (TAUH)
      Tammerfors, Pirkanmaa, Finland
  • 1995-2013
    • University of Tampere
      • • Medical School
      • • Department of Internal Medicine
      Tampere, Western Finland, Finland
  • 2003
    • University of Helsinki
      • Department of Oral Medicine
      Helsinki, Uusimaa, Finland