[Flucloxacillin-induced hypokalemia]. / Door flucloxacilline geïnduceerde hypokaliëmie.

Flucloxacillin-induced hypokalaemia can be progressive and life-threatening, despite of potassium supplementation. In this case description, a high dose of intravenous flucloxacillin was started after a 68-year-old patient presented with an infected knee replacement. After two days, hypokalaemia was noted with an inadequate response to potassium supplementation. It was decided to change antibiotics and increase potassium supplementation, with good results. It is advisable to include monitoring of potassium levels in local treatment protocols when flucloxacillin is prescribed.

Plasma sodium, extracellular fluid volume, and blood pressure in healthy men.

In the general population we recently reported a consistent association between plasma sodium and volume markers, suggesting that individuals with higher plasma sodium have higher extracellular fluid volume (ECFV). To test this hypothesis, we analyzed the association between plasma sodium and directly measured ECFV (iothalamate distribution volume) in healthy men. Second, we studied whether plasma sodium is associated with blood pressure. We analyzed data from 70 men (age 24 ± 7 years) at the end of two 7-day periods on a low-sodium diet (LS, 50 mmol Na/24 h) and a high-sodium diet (HS, 200 mmol Na/24 h), respectively. The association of plasma sodium with blood pressure was assessed in the combined data of the different sodium intakes by linear mixed effects models. A positive univariable association between plasma sodium and ECFV was found during HS (ß = 0.24, p = 0.042) and LS (ß = 0.23, p = 0.058), respectively. Individual values of plasma sodium on LS and HS diet were strongly correlated (ß = 0.68, p < 0.001), as were values for ECFV (ß = 0.54, p < 0.001). In the combined data set plasma sodium level was significantly associated with ECFV (B [SE] = 0.10 [0.04], p = 0.02), and systolic blood pressure (SBP, B [SE] = 0.73 [0.26], p = 0.006), independent of ECFV. In conclusion, plasma sodium concentration is positively associated with ECFV on both LS and HS intake. Our data confirm and extend prior data on individual regulation of plasma sodium and suggest that this is associated with individuality of the regulation of ECFV. Finally, plasma sodium level is associated with SBP, independent of ECFV and diet.

A Case of Hypercalcemia in an Immunocompetent Patient with Disseminated Mycobacterium marinum Infection with a Rain Barrel as the Most Likely Primary Source.

Infection with Mycobacterium marinum is common in fish, and so human infection usually arises from contact with contaminated water or fish. A solitary papulonodular lesion on a finger or hand is the typical presentation. Disseminated infections are rare and mostly seen in immunocompromised patients. We present a rare case of disseminated M. marinum infection presenting with polyarthritis, tenosynovitis, dactylitis, and (sub)cutaneous and intramuscular lesions in an immunocompetent patient. This case was complicated by hypercalcemia, renal failure and eventually death. A contaminated rain barrel was most likely the primary source of the infection. LEARNING POINTS: Given the similarities, it is key to differentiate Crohn's disease from intestinal tuberculosis as early as possible.Patients undergoing colonoscopy for possible Crohn's disease should have colonic biopsy samples sent for AFB culture.Consider investigations for intestinal tuberculosis in uncontrolled Crohn's disease where intestinal tuberculosis has not been worked up previously.

Rapid Progression of Autosomal Dominant Polycystic Kidney Disease: Urinary Biomarkers as Predictors.

BACKGROUND: Markers currently used to predict the likelihood of rapid disease progression in patients with autosomal dominant polycystic kidney disease (ADPKD) are expensive and time consuming to assess and often have limited sensitivity. New, easy-to-measure markers are therefore needed that alone or in combination with conventional risk markers can predict the rate of disease progression. In the present study, we investigated the ability of tubular damage and inflammation markers to predict kidney function decline. METHODS: At baseline, albumin, immunoglobulin G, kidney injury molecule 1, ß2 microglobulin (ß2MG), heart-type fatty acid-binding protein, neutrophil gelatinase-associated lipocalin, and monocyte chemotactic protein-1 -(MCP-1) were measured in 24-h urine samples of patients participating in a study investigating the therapeutic efficacy of lanreotide in ADPKD. Individual change in estimated glomerular filtration rate (eGFR) during follow-up was calculated using mixed-model analysis taking into account 13 -eGFRs (chronic kidney disease EPIdemiology) per patient. Logistic regression analysis was used to select urinary biomarkers that had the best association with rapidly progressive disease. The predictive value of these selected urinary biomarkers was compared to other risk scores using C-statistics. RESULTS: Included were 302 patients of whom 53.3% were female, with an average age of 48 ± 7 years, eGFR of 52 ± 12 mL/min/1.73 m2, and a height-adjusted total kidney volume (htTKV) of 1,082 (736-1,669) mL/m. At baseline, all urinary damage and inflammation markers were associated with baseline eGFR, also after adjustment for age, sex and baseline htTKV. For longitudinal analyses only patients randomized to standard care were considered (n = 152). A stepwise backward analysis revealed that ß2MG and MCP-1 showed the strongest association with rapidly progressive disease. A urinary biomarker score was created by summing the ranking of tertiles of ß2MG and MCP-1 excretion. The predictive value of this urinary biomarker score was higher compared to that of the Mayo htTKV classification (area under the curve [AUC] 0.73 [0.64-0.82] vs. 0.61 [0.51-0.71], p = 0.04) and comparable to that of the predicting renal outcomes in -ADPKD score (AUC 0.73 [0.64-0.82] vs. 0.65 [0.55-0.75], p = 0.18). In a second independent cohort with better kidney function, similar results were found for the urinary biomarker score. CONCLUSION: Measurement of urinary ß2MG and MCP-1 excretion allows selection of ADPKD patients with rapidly progressive disease, with a predictive value comparable to or even higher than that of TKV or PKD mutation. Easy and inexpensive to measure urinary markers therefore hold promise to help predict prognosis in ADPKD.

Lanreotide Reduces Liver Growth In Patients With Autosomal Dominant Polycystic Liver and Kidney Disease.

BACKGROUND & AIMS: Polycystic liver disease is the most common extrarenal manifestation of autosomal dominant polycystic kidney disease (ADPKD). There is need for robust long-term evidence for the volume-reducing effect of somatostatin analogues. We made use of data from an open-label, randomized trial to determine the effects of lanreotide on height-adjusted liver volume (hTLV) and combined height-adjusted liver and kidney volume (hTLKV) in patients with ADPKD. METHODS: We performed a 120-week study comparing the reno-protective effects of lanreotide vs standard care in 305 patients with ADPKD (the DIPAK-1 study). For this analysis, we studied the 175 patients with polycystic liver disease with hepatic cysts identified by magnetic resonance imaging and liver volume ≥2000 mL. Of these, 93 patients were assigned to a group that received lanreotide (120 mg subcutaneously every 4 weeks) and 82 to a group that received standard care (blood pressure control, a sodium-restricted diet, and antihypertensive agents). The primary endpoint was percent change in hTLV between baseline and end of treatment (week 120). A secondary endpoint was change in hTLKV. RESULTS: At 120 weeks, hTLV decreased by 1.99% in the lanreotide group (95% confidence interval [CI], -4.21 to 0.24) and increased by 3.92% in the control group (95% CI, 1.56-6.28). Compared with the control group, lanreotide reduced the growth of hTLV by 5.91% (95% CI, -9.18 to -2.63; P < .001). Growth of hTLV was still reduced by 3.87% at 4 months after the last injection of lanreotide compared with baseline (95% CI, -7.55 to -0.18; P = .04). Lanreotide reduced growth of hTLKV by 7.18% compared with the control group (95% CI, -10.25 to -4.12; P < .001). CONCLUSIONS: In this subanalysis of a randomized trial of patients with polycystic liver disease due to ADPKD, lanreotide for 120 weeks reduced the growth of liver and combined liver and kidney volume. This effect was still present 4 months after the last injection of lanreotide. ClinicalTrials.gov, Number: NCT01616927.

Effect of Lanreotide on Kidney Function in Patients With Autosomal Dominant Polycystic Kidney Disease: The DIPAK 1 Randomized Clinical Trial.

Importance: Autosomal dominant polycystic kidney disease (ADPKD) is characterized by progressive cyst formation in both kidneys and loss of renal function, eventually leading to a need for kidney replacement therapy. There are limited therapeutic management options. Objective: To examine the effect of the somatostatin analogue lanreotide on the rate of kidney function loss in patients with later-stage ADPKD. Design, Setting, and Participants: An open-label randomized clinical trial with blinded end point assessment that included 309 patients with ADPKD from July 2012 to March 2015 at 4 nephrology outpatient clinics in the Netherlands. Eligible patients were 18 to 60 years of age and had an estimated glomerular filtration rate (eGFR) of 30 to 60 mL/min/1.73 m2. Follow-up of the 2.5-year trial ended in August 2017. Interventions: Patients were randomized to receive either lanreotide (120 mg subcutaneously once every 4 weeks) in addition to standard care (n = 153) or standard care only (target blood pressure <140/90 mm Hg; n = 152). Main Outcomes and Measures: Primary outcome was annual change in eGFR assessed as slope through eGFR values during the 2.5-year treatment phase. Secondary outcomes included change in eGFR before vs after treatment, incidence of worsening kidney function (start of dialysis or 30% decrease in eGFR), change in total kidney volume and change in quality of life (range: 1 [not bothered] to 5 [extremely bothered]). Results: Among the 309 patients who were randomized (mean [SD] age, 48.4 [7.3] years; 53.4% women), 261 (85.6%) completed the trial. Annual rate of eGFR decline for the lanreotide vs the control group was -3.53 vs -3.46 mL/min/1.73 m2 per year (difference, -0.08 [95% CI, -0.71 to 0.56]; P = .81). There were no significant differences for incidence of worsening kidney function (hazard ratio, 0.87 [95% CI, 0.49 to 1.52]; P = .87), change in eGFR (-3.58 vs -3.45; difference, -0.13 mL/min/1.73 m2 per year [95% CI, -1.76 to 1.50]; P = .88), and change in quality of life (0.05 vs 0.07; difference, -0.03 units per year [95% CI, -0.13 to 0.08]; P = .67). The rate of growth in total kidney volume was lower in the lanreotide group than the control group (4.15% vs 5.56%; difference, -1.33% per year [95% CI, -2.41% to -0.24%]; P = .02). Adverse events in the lanreotide vs control group included injection site discomfort (32% vs 0.7%), injection site papule (5.9% vs 0%), loose stools (91% vs 6.6%), abdominal discomfort (79% vs 20%), and hepatic cyst infections (5.2% vs 0%). Conclusions and Relevance: Among patients with later-stage autosomal dominant polycystic kidney disease, treatment with lanreotide compared with standard care did not slow the decline in kidney function over 2.5 years of follow-up. These findings do not support the use of lanreotide for treatment of later-stage autosomal dominant polycystic kidney disease. Trial Registration: ClinicalTrials.gov Identifier: NCT01616927.

Sex differences in renin-angiotensin-aldosterone system affect extracellular volume in healthy subjects.

Several studies reported sex differences in aldosterone. It is unknown whether these differences are associated with differences in volume regulation. Therefore we studied both aldosterone and extracellular volume in men and women on different sodium intakes. In healthy normotensive men ( n = 18) and premenopausal women ( n = 18) we investigated plasma aldosterone, blood pressure, and extracellular volume (125I-iothalamate), during both low (target intake 50 mmol Na+/day) and high sodium intake (target intake 200 mmol Na+/day) in a crossover setup. Furthermore, we studied the adrenal response to angiotensin II infusion (0.3, 1.0, and 3.0 ng·kg-1·min-1 for 1 h) on both sodium intakes. Men had a significantly higher plasma aldosterone, extracellular volume, and systolic blood pressure than women during high sodium intake ( P < 0.05). During low sodium intake, extracellular volume and blood pressure were higher in men as well ( P < 0.05), whereas the difference in plasma aldosterone was no longer significant ( P = 0.252). The adrenal response to exogenous angiotensin II was significantly lower in men than in women on both sodium intakes. Constitutive sex differences in the regulation of aldosterone, characterized by a higher aldosterone and a lower adrenal response to exogenous angiotensin II infusion in men, are associated with a higher extracellular volume and blood pressure in men. These findings suggest that sex differences in the regulation of aldosterone contribute to differences in volume regulation between men and women.

The Association of Combined Total Kidney and Liver Volume with Pain and Gastrointestinal Symptoms in Patients with Later Stage Autosomal Dominant Polycystic Kidney Disease.

BACKGROUND: There is an ongoing debate if and how kidney and liver volume are associated with pain and gastrointestinal (GI) symptoms in autosomal dominant polycystic kidney disease (ADPKD) patients. Since both kidney and liver volume could interact, we investigated whether combined total kidney and liver volume had stronger associations with ADPKD-related pain and GI symptoms than the volumes of the organs separately. METHODS: We used baseline data from the DIPAK-1 study, which included ADPKD patients with an estimated glomerular filtration rate (eGFR) between 30 and 60 mL/min/1.73 m2. MR imaging was performed to measure height-adjusted total kidney volume (hTKV), height-adjusted total liver volume (hTLV) and the combination of both (height-adjusted total kidney liver volume [hTKLV]). RESULTS: Three hundred nine ADPKD patients were included with a mean age of 48 ± 7 years, 53% female, eGFR 50 ± 11 mL/min/1.73 m2 and median hTKV, hTLV and hTKLV of 1,095 (758-1,669), 1,173 (994-1,523) and 2,496 (1,972-3,352) mL/m, respectively. ADPKD-related pain and GI symptoms were present in, respectively, 27.5 and 61.2% of patients. Gender was no effect modifier in the association between kidney and/or liver volume, and symptom burden, indicating that all models could be tested in the overall study population. hTKLV and hTLV were significantly associated with pain and GI symptoms, whereas hTKV was not. Model testing revealed that the associations of pain and GI symptoms with hTKLV were significantly stronger than with hTKV (p = 0.04 and p = 0.04, respectively) but not when compared to hTLV (p = 0.2 and p = 0.5, respectively). CONCLUSIONS: This study indicates that combined kidney and liver volume was associated with the presence and severity of pain and GI symptoms in ADPKD, with a more prominent role for hTLV than for hTKV.

Hepatic Cyst Infection During Use of the Somatostatin Analog Lanreotide in Autosomal Dominant Polycystic Kidney Disease: An Interim Analysis of the Randomized Open-Label Multicenter DIPAK-1 Study.

INTRODUCTION AND AIMS: The DIPAK-1 Study investigates the reno- and hepatoprotective efficacy of the somatostatin analog lanreotide compared with standard care in patients with later stage autosomal dominant polycystic kidney disease (ADPKD). During this trial, we witnessed several episodes of hepatic cyst infection, all during lanreotide treatment. We describe these events and provide a review of the literature. METHODS: The DIPAK-1 Study is an ongoing investigator-driven, randomized, controlled, open-label multicenter trial. Patients (ADPKD, ages 18-60 years, estimated glomerular filtration rate 30-60 mL/min/1.73 m2) were randomized 1:1 to receive lanreotide 120 mg subcutaneously every 28 days or standard care during 120 weeks. Hepatic cyst infection was diagnosed by local physicians. RESULTS: We included 309 ADPKD patients of which seven (median age 53 years [interquartile range: 48-55], 71% female, median estimated glomerular filtration rate 42 mL/min/1.73 m2 [interquartile range: 41-58]) developed eight episodes of hepatic cyst infection during 342 patient-years of lanreotide use (0.23 cases per 10 patient-years). These events were limited to patients receiving lanreotide (p < 0.001 vs. standard care). Baseline characteristics were similar between subjects who did or did not develop a hepatic cyst infection during lanreotide use, except for a history of hepatic cyst infection (29 vs. 0.7%, p < 0.001). Previous studies with somatostatin analogs reported cyst infections, but did not identify a causal relationship. CONCLUSIONS: These data suggest an increased risk for hepatic cyst infection during use of somatostatin analogs, especially in ADPKD patients with a history of hepatic cyst infection. The main results are still awaited to fully appreciate the risk-benefit ratio. CLINICALTRIALS. GOV IDENTIFIER: NCT 01616927.

International Multi-Specialty Delphi Survey: Identification of Diagnostic Criteria for Hepatic and Renal Cyst Infection.

BACKGROUND: Cyst infection is one of the complications of autosomal dominant polycystic kidney disease and polycystic liver disease. The diagnosis is typically made on a mix of clinical, laboratory and imaging abnormalities but the importance of individual items is uncertain. We aimed to perform a Delphi survey amongst physicians to achieve consensus on diagnostic criteria. METHODS: We retrieved diagnostic items from the literature and conducted physician and patient interviews. All items were combined to create the online questionnaire. Participants rated each item during 3 consecutive rounds. Items were rated for diagnostic helpfulness for hepatic and renal cyst infection on a 9-point scale with anchors, from extremely unimportant (n = 1) to extremely important (n = 9). We determined consensus with the disagreement index. The median rating of each item was calculated and categorized into inappropriate (≤3.4), uncertain (3.5-6.4) or appropriate (≥6.5). By combining all items that reached an appropriate consensus rating, we developed a diagnostic algorithm based on expert consensus. RESULTS: We invited 58 physicians to participate in the survey. In total, 35 (60%) responded to round 1 of which 91% (n = 32) and 86% (n = 30) responded to round 2 and 3, respectively. The final panel included 23 nephrologists, 5 hepatologists, a nuclear medicine specialist and an infectious disease physician from 11 countries (male 67%, mean age 47 ± 11 years, median clinical experience 21 years). The panel rated the diagnostic helpfulness of 59 potential items. Ultimately, 22 hepatic and 26 renal items were rated appropriate, including positive blood cultures and fluorodeoxyglucose positron-emission CT imaging. Ultrasonography and absence of intracystic bleeding were amongst those deemed uncertain or inappropriate. Subsequently, by combining items rated appropriate, we developed a clinical tool to diagnose hepatic and renal cyst infection. CONCLUSIONS: We identified diagnostic items for hepatic and renal cyst infection and developed an expert-based diagnostic algorithm, which may aid physicians in the diagnostic work-up. A prospective study is necessary to validate this algorithm.

Estimation of total kidney volume in autosomal dominant polycystic kidney disease.

BACKGROUND: In autosomal dominant polycystic kidney disease (ADPKD), obtaining measured total kidney volume (mTKV) by magnetic resonance (MR) imaging and manual tracing is time consuming. Two alternative MR imaging methods have recently been proposed to estimate TKV (eTKVellipsoid and eTKVPANK), which require less time. STUDY DESIGN: Cross-sectional and longitudinal diagnostic test study. SETTING & PARTICIPANTS: Patients with ADPKD with a wide range of kidney function and an approved T2-weighted MR image obtained at the University Medical Centers of Groningen, Leiden, Nijmegen, and Rotterdam, the Netherlands, in 2007 to 2014. Test set for assessing reproducibility, n=10; cohort for cross-sectional analyses, n=220; and cohort for longitudinal analyses, n=48. INDEX TESTS: Average times for eTKVellipsoid and eTKVPANK were 5 and 15 minutes, respectively. Bias is defined as (mTKV - eTKV)/mTKV × 100%; precision, as one standard deviation of bias. REFERENCE TESTS: mTKV using manual tracing to calculate the area within kidney boundaries times slice thickness. Average time for mTKV was 55 minutes. RESULTS: In the test set, intra- and intercoefficients of variation for mTKV, eTKVellipsoid, and eTKVPANK were 1.8% and 2.3%, 3.9% and 6.3%, and 3.0% and 3.4%, respectively. In cross-sectional analysis, baseline mTKV, eTKVellipsoid, and eTKVPANK were 1.96 (IQR, 1.28-2.82), 1.93 (IQR, 1.25-2.82), and 1.81 (IQR, 1.17-2.62) L, respectively. In cross-sectional analysis, bias was 0.02% ± 3.2%, 1.4% ± 9.2%, and 4.6% ± 7.6% for repeat mTKV, eTKVellipsoid, and eTKVPANK, respectively. In longitudinal analysis, no significant differences were observed between percentage change in mTKV (16.7% ± 17.1%) and percentage change in eTKVellipsoid (19.3% ± 16.1%) and eTKVPANK (17.8% ± 16.1%) over 3 years. LIMITATIONS: Results for follow-up data should be interpreted with caution because of the limited number of patients. CONCLUSIONS: Both methods for eTKV perform relatively well compared to mTKV and can detect change in TKV over time. Because eTKVellipsoid requires less time than eTKVPANK, we suggest that this method may be preferable in clinical care.

Gender differences in response to acute and chronic angiotensin II infusion: a translational approach.

Women with renal disease progress at a slower rate to end stage renal disease than men. As angiotensin II has both hemodynamic and direct renal effects, we hypothesized that the female protection may result from gender differences in responses to angiotensin II. Therefore, we studied gender differences in response to angiotensin II, during acute (human) and chronic (rats) angiotensin II administration. In young healthy men (n = 18) and women (n = 18) we studied the responses of renal hemodynamics ((125)I-iothalamate and (131)I-Hippuran) and blood pressure to graded angiotensin II infusion (0.3, 1.0, and 3.0 ng/kg/min for 1 h). Men had increased responses of diastolic blood pressure (P = 0.01), mean arterial pressure (P = 0.05), and a more pronounced decrease in effective renal plasma flow (P = 0.009) than women. We measured the changes in proteinuria and blood pressure in response to chronic administration (200 ng/kg/min for 3 weeks) of angiotensin II in rats. Male rats had an increased response of proteinuria compared with females (GEE analysis, P = 0.001). Male, but not female, angiotensin II-treated rats had increased numbers of renal interstitial macrophages compared to sham-treated rats (P < 0.001). In conclusion, gender differences are present in the response to acute and chronic infusion of angiotensin II. Difference in angiotensin II sensitivity could play a role in gender differences in progression of renal disease.

Higher filtration fraction in formerly early-onset preeclamptic women without comorbidity.

Formerly preeclamptic women have an increased risk for developing end-stage renal disease, which has been attributed to altered renal hemodynamics and abnormalities in the renin-angiotensin-aldosterone system. Whether this is due to preeclampsia itself or to comorbid conditions is unknown. Renal hemodynamics and responsiveness to ANG II during low Na(+) intake (7 days, 50 mmol Na(+)/24 h) and high Na(+) (HS) intake (7 days, 200 mmol Na(+)/24 h) were studied in 18 healthy normotensive formerly early-onset preeclamptic women (fPE women) and 18 healthy control subjects (fHP women), all selected for absence of comorbidity. At the end of each diet, renal hemodynamics and blood pressure were measured before and during graded ANG II infusion. Both HS intake and former preeclampsia increased filtration fraction (FF) without an interaction between the two. FF was highest during HS intake in fPE women [0.31 ± 0.12 vs. 0.29 ± 0.11 in fHP women, generalized estimating equation analysis (body mass index corrected), P = 0.03]. The renal response to ANG II infusion was not different between groups. In conclusion, fPE women have a higher FF compared with fHP women. As this was observed in the absence of comorbidity, preeclampsia itself might exert long-term effects on renal hemodynamics. However, we cannot exclude the presence of prepregnancy alterations in renal function, which, in itself, lead to an increased risk for preeclampsia. In experimental studies, an elevated FF has been shown to play a pathogenic role in the development of hypertension and renal damage. Future studies, however, should evaluate whether the subtle differences in renal hemodynamics after preeclampsia contribute to the increased long-term renal risk after preeclampsia.

A stepwise approach for effective management of chronic pain in autosomal-dominant polycystic kidney disease.

Chronic pain, defined as pain existing for >4-6 weeks, affects >60% of patients with autosomal-dominant polycystic disease (ADPKD). It can have various causes, indirectly or directly related to the increase in kidney and liver volume in these patients. Chronic pain in ADPKD patients is often severe, impacting physical activity and social relationships, and frequently difficult to manage. This review provides an overview of pathophysiological mechanisms that can lead to pain and discusses the sensory innervation of the kidneys and the upper abdominal organs, including the liver. In addition, the results of a systematic literature search of ADPKD-specific treatment options are presented. Based on pathophysiological knowledge and evidence derived from the literature an argumentative stepwise approach for effective management of chronic pain in ADPKD is proposed.

Effects of sodium restriction and hydrochlorothiazide on RAAS blockade efficacy in diabetic nephropathy: a randomised clinical trial.

BACKGROUND: Reduction of dietary sodium intake or diuretic treatment increases renin-angiotensin-aldosterone system (RAAS) blockade efficacy in non-diabetic nephropathy. We aimed to investigate the effect of sodium restriction and the diuretic hydrochlorothiazide, separately and in combination, added to RAAS blockade on residual albuminuria in patients with type 2 diabetic nephropathy. METHODS: In this multicentre, double-blind, placebo-controlled, crossover randomised trial, we included patients with type 2 diabetic nephropathy. Main entry criteria were microalbuminaria or macroalbuminuria, and creatinine clearance of 30 mL/min or higher with less than 6 mL/min decline in the previous year. We tested the separate and combined effects of sodium restriction (dietary counselling in the outpatient setting) and hydrochlorothiazide (50 mg daily), added to standardised maximal angiotensin-converting enzyme (ACE) inhibition (lisinopril 40 mg daily), on albuminuria (primary endpoint). Patients were given hydrochlorothiazide (50 mg per day) or placebo during four treatment periods of 6 weeks. Both treatments were combined with regular sodium diet or sodium restriction (target sodium intake 50 mmol Na(+) per day). The 6-week treatment periods were done consecutively in a random order. Patients were randomised in blocks of two patients. The trial was analysed by intention to treat. The trial is registered with TrialRegister.nl, number 2366. FINDINGS: Of 89 eligible patients, 45 were included in the study. Both sodium restriction and hydrochlorothiazide significantly reduced albuminuria, irrespective of treatment sequence. Residual geometric mean albuminuria with baseline treatment was 711 mg per day (95% CI 485-1043); it was significantly reduced by sodium restriction (393 mg per day [258-599], p=0·0002), by hydrochlorothiazide (434 mg per day [306-618], p=0·0003), and to the greatest extent by their combination (306 mg per day [203-461], p<0·0001). Orthostatic complaints were present in two patients (4%) during baseline treatment, five (11%) during addition of sodium restriction, five (11%) during hydrochlorothiazide treatment, and 12 (27%) during combination treatment. No serious adverse events occurred. INTERPRETATION: We conclude that sodium restriction is an effective non-pharmacological intervention to increase RAAS blockade efficacy in type 2 diabetic nephropathy. FUNDING: None.

Rationale and design of the DIPAK 1 study: a randomized controlled clinical trial assessing the efficacy of lanreotide to Halt disease progression in autosomal dominant polycystic kidney disease.

BACKGROUND: There are limited therapeutic options to slow the progression of autosomal dominant polycystic kidney disease (ADPKD). Recent clinical studies indicate that somatostatin analogues are promising for treating polycystic liver disease and potentially also for the kidney phenotype. We report on the design of the DIPAK 1 (Developing Interventions to Halt Progression of ADPKD 1) Study, which will examine the efficacy of the somatostatin analogue lanreotide on preservation of kidney function in ADPKD. STUDY DESIGN: The DIPAK 1 Study is an investigator-driven, randomized, multicenter, controlled, clinical trial. SETTING & PARTICIPANTS: We plan to enroll 300 individuals with ADPKD and estimated glomerular filtration rate (eGFR) of 30-60 mL/min/1.73 m(2) who are aged 18-60 years. INTERVENTION: Patients will be randomly assigned (1:1) to standard care or lanreotide, 120 mg, subcutaneously every 28 days for 120 weeks, in addition to standard care. OUTCOMES: Main study outcome is the slope through serial eGFR measurements starting at week 12 until end of treatment for lanreotide versus standard care. Secondary outcome parameters include change in eGFR from pretreatment versus 12 weeks after treatment cessation, change in kidney volume, change in liver volume, and change in quality of life. MEASUREMENTS: Blood and urine will be collected and questionnaires will be filled in following a fixed scheme. Magnetic resonance imaging will be performed for assessment of kidney and liver volume. RESULTS: Assuming an average change in eGFR of 5.2 ± 4.3 (SD) mL/min/1.73 m(2) per year in untreated patients, 150 patients are needed in each group to detect a 30% reduction in the rate of kidney function loss between treatment groups with 80% power, 2-sided α = 0.05, and 20% protocol violators and/or dropouts. LIMITATIONS: The design is an open randomized controlled trial and measurement of our primary end point does not begin at randomization. CONCLUSIONS: The DIPAK 1 Study will show whether subcutaneous administration of lanreotide every 4 weeks attenuates disease progression in patients with ADPKD.

Higher body mass index is associated with higher fractional creatinine excretion in healthy subjects.

BACKGROUND: Accurate glomerular filtration rate (GFR) measurement in normal to high range is important for epidemiological studies and workup for kidney donation. Creatinine-based equations perform poorly in this GFR range. Creatinine clearance (CrCl) provides a substitute, provided urine is collected accurately and tubular creatinine handling can be accounted for. The latter is poorly characterized in the normal GFR range. METHODS: Therefore, we studied performance of CrCl, fractional creatinine excretion (FE(creat)) and its determinants in 226 potential kidney donors (47% males, mean 53 ± 10 years). GFR was assessed as (125)I-iothalamate clearance, simultaneously with 2-h CrCl and 24-h CrCl. RESULTS: Mean GFR was 101 ± 18, 2-h CrCl 110 ± 20 and 24-h CrCl 106 ± 29 mL/min/1.73 m(2). Mean bias of 24 h CrCl was 7.4 [inter-quartile range -6.7 to 20.0] mL/min/1.73 m(2), precision (R(2)) 0.39 and 30% accuracy 82%. Mean FE(creat) was 110 ± 11%. FE(creat) correlated with body mass index (BMI) (r = 0.34, P < 0.001). Consequently, bias of 24-h CrCl increased from 2.7 (inter-quartile range -6.5 to 16.7) to 8.6 (inter-quartile range -5.8 to 20.5) and 12.6 (inter-quartile range 7.0 to 25.4) mL/min in subjects with BMI <25, 25-30 and >30 kg/m(2), respectively (P < 0.05). On multivariate analysis, BMI and gender were predictors of FE(creat). CONCLUSIONS: CrCl systematically overestimates GFR in healthy subjects. The overestimation significantly correlates with BMI, with higher FE(creat) in subjects with higher BMI. The impact of BMI on tubular creatinine secretion can be accounted for, when using CrCl for GFR assessment in the normal to high range, by the following formula: GFR = 24-h CrCl - (22.75 + 0.76 × BMI - 0.29 × mean arterial pressure (-6.11 if female).

Response to angiotensin-converting enzyme inhibition is selectively blunted by high sodium in angiotensin-converting enzyme DD genotype: evidence for gene-environment interaction in healthy volunteers.

BACKGROUND: Renin-angiotensin-aldosterone system blockade is a cornerstone in cardiovascular protection. Angiotensin-converting enzyme (ACE)-DD genotype has been associated with resistance to angiotensin-converting enzyme inhibition (ACEi), but data are conflicting. As sodium intake modifies the effect of ACEi as well as the genotype-phenotype relationship, we hypothesize gene-environment interaction between sodium-status, the response to ACEi, and ACE genotype. METHOD: Thirty-five male volunteers (26 ± 9 years; II n = 6, ID n = 18, DD n = 11) were studied during placebo and ACEi (double blind, enalapril 20 mg/day) on low [7 days 50 mmol Na/day (low salt)] and high [7 days 200 mmol Na/day (high salt)] sodium, with a washout of 6 weeks in-between. After each period mean arterial pressure (MAP) was measured before and during graded infusion of angiotensin II (Ang II). RESULTS: During high salt, ACEi reduced MAP in II and ID, but not in DD [II: 88 (78-94) versus 76 (72-88); ID: 87 (84-91) versus 83 (79-87); both P < 0.05 and DD: 86 (82-96) versus 88 (80-90); ns, P < 0.05 between genotypes]. However, during low salt, ACEi reduced MAP in all genotype groups [II: 83 (78-89) versus 77 (72-83); ID: 88 (84-91) versus 82 (78-86); DD: 84 (80-91) versus 81 (75-85); all P < 0.05]. During high salt + ACEi, the Ang II response was blunted in DD, with an 18% rise in MAP during the highest dose versus 22 and 31% in ID and II (P < 0.05). Low salt annihilated these differences. CONCLUSION: In healthy participants, the MAP response to ACEi is selectively blunted in DD genotype during high salt, accompanied by blunted sensitivity to Ang II. Low salt corrects both abnormalities. Further analysis of this gene-environment interaction in patients may contribute to strategies for improvement of individual treatment efficacy.

Rise in extracellular fluid volume during high sodium depends on BMI in healthy men.

A high sodium (HS) intake is associated to increased cardiovascular and renal risk, especially in overweight subjects. We hypothesized that abnormal sodium and fluid handling is involved, independent of hypertension or insulin resistance. Therefore, we studied the relation between BMI and sodium-induced changes in extracellular fluid volume (ECFV; distribution volume of (125)I-iothalamate) in 78 healthy men, not selected for BMI. A total of 78 subjects with a median BMI of 22.5 (range: 19.2-33.9 kg/m(2)) were studied after 1 week on a low sodium (LS) diet (50 mmol Na(+)/d) and after 1 week on HS (200 mmol Na(+)/d). The change from LS to HS resulted in an increase in ECFV of 1.2 +/- 1.8 l. Individual changes in ECFV were correlated to BMI (r = 0.361, P < 0.01). Furthermore, in response to HS, a higher BMI was associated to a higher rise in filtered load of sodium (FL(Na(+)) = [Na(+)] x GFR, r = 0.281, P < 0.05). Thus, a shift to HS leads to a larger rise in ECFV in healthy subjects with higher BMI, associated with an elevated FL(Na(+)) during HS. Although no hypertension occurred in these healthy subjects, our data provide a potential explanation for the interaction of sodium intake and BMI on cardiovascular and renal risk. Exaggerated fluid retention may be an early pathogenic factor in the cardiorenal complications of overweight.

Feasibility and impact of the measurement of extracellular fluid volume simultaneous with GFR by 125I-iothalamate.

The feasibility, validity, and possible applications of the assessment of extracellular fluid volume (ECFV) simultaneous with glomerular filtration rate (GFR) were assessed in a series of validation studies using the constant infusion method of (125)I-iothalamate (IOT). In 48 subjects with a broad range of GFR, distribution volume (V(d)) of IOT corresponded well with V(d) bromide (16.71 +/- 3.0 and 16.73 +/- 3.2 l, respectively, not significant), with a strong correlation (r = 0.933, P < 0.01) and without systematic deviations. Reproducibility assessment in 25 healthy male subjects showed coefficients of variation of 8.6% of duplicate measurement of V(d) IOT during strictly standardized (50 mmol Na(+)/d) sodium intake. An increase in dietary sodium intake (200 mmol Na(+)/d) induced a corresponding rise in V(d) IOT of 1.11 +/- 1.5 l (P < 0.01). In 158 healthy prospective kidney donors, the impact of indexing of GFR to ECFV was analyzed. Age, gender, height, and body surface area (BSA) were determinants of GFR. Whereas GFR, GFR/BSA, and GFR/height were gender-dependent, GFR/ECFV was gender-independent and not related to height or BSA. This supports the potential of normalizing GFR by ECFV. Thus, ECFV can be simultaneously assessed with GFR by the constant infusion method using IOT. After appropriate validation, also other GFR tracers could be used for such a simultaneous estimation, providing a valuable resource of data on ECFV in renal studies and, moreover, allowing GFR to be indexed to the body fluid compartment it clears: the ECFV.