MgCaCO3 versus CaCO3 in peritoneal dialysis patients--a cross-over pilot trial.

BACKGROUND: Despite adverse effects such as constipation, vascular calcification, and hypercalcemia, calcium-based salts are relatively affordable and effective phosphate binders that remain in widespread use in the dialysis population. We conducted a pilot study examining whether the use of a combined magnesium/calcium-based binder was as effective as calcium carbonate at lowering serum phosphate levels in peritoneal dialysis (PD) patients. METHODS: This was a cross-over, investigator-masked pilot study in which prevalent PD patients received calcium carbonate alone (200 mg calcium per tablet) or calcium magnesium carbonate (100 mg calcium, 85 mg magnesium per tablet). Primary outcome was serum phosphate level at 3 months. Analysis was as per protocol. RESULTS: Twenty patients were recruited, 17 completed the study. Mean starting dose was 11.35 ± 7.04 pills per day of MgCaCO3 and 9.00 ± 4.97 pills per day of CaCO3. Mean phosphate levels fell from 2.13 mmol/L to 2.01 mmol/L (95% confidence interval (CI): 1.76 - 2.30, p = 0.361) in the MgCaCO3 group, and 1.81 mmol/L (95% CI: 1.56 - 2.0, p = 0.026) in the CaCO3 alone group. Six (35%) patients taking MgCaCO3 and 9 (54%) taking CaCO3 alone achieved Kidney Disease Outcomes Quality Initiative (KDOQI) serum phosphate targets at 3 months. Diarrhea developed in 9 patients taking MgCaCO3 and 3 taking CaCO3. Serum magnesium exceeded 1.4 mmol/L in 5 patients taking MgCaCO3 while serum calcium exceeded 2.65 mmol/L in 3 patients receiving CaCO3. When compared to the initial dose, the prescribed dose at 3 months was reduced by 44% (to 6.41 tablets/day) in the MgCaCO3 group and by 8% (to 8.24 pills per day) in the CaCO3 alone group. CONCLUSION: Compared with CaCO3 alone, the preparation and dose of MgCaCO3 used in this pilot study was no better at lowering serum phosphate levels in PD patients, and was associated with more dose-limiting side effects.

Variability in CKD stage in outpatients followed in two large renal clinics.

OBJECTIVE: Chronic kidney disease (CKD) is staged by glomerular filtration rate (GFR). CKD stages sometimes vary between routine office visits, and it is unknown if this impacts renal and patient survival separately from a cross-sectional CKD stage value. We quantified and categorized CKD stage variability in a large group of outpatients and correlated this with clinical and demographic features and with renal and patient survival. METHODS: All estimated GFRs were staged in the first observation period. CKD stages were then categorized as static, improving, worsening, or fluctuating. Logistic regression analysis was performed to identify clinical variables associated with CKD stage variability. Death and dialysis progression rates were then collected and analyzed using Cox proportional regression. RESULTS: During a 1.1-year observation period, 1,262 patients (mean age 71.25 years) had a mean 5 eGFR's. CKD stages were static in 60.4%, worsened in 14.4%, improved in 7.4%, and fluctuated in 17.2% of patients. Secondary analysis revealed heavy proteinuria and East Asian ethnicity to be negatively, and diabetes mellitus and previous acute kidney injury to be positively associated with improving CKD stages. Cox proportional regression of 902 patients analyzed 2.3 years later revealed a negative association with improving CKD stage and subsequent need for dialysis. CONCLUSIONS: CKD stage changed in 40% of 1,262 elderly patients when determined 5 times in just over 1 year. Improving CKD stage was the only variability pattern significantly associated with any of the clinical outcomes when assessed 2.3 years later, being unlikely to be linked with subsequent need for dialysis.

Prevention of catheter lumen occlusion with rT-PA versus heparin (Pre-CLOT): study protocol of a randomized trial [ISRCTN35253449].

BACKGROUND: Many patients with end-stage renal disease use a central venous catheter for hemodialysis access. A large majority of these catheters malfunction within one year of insertion, with up to two-thirds due to thrombosis. The optimal solution for locking the catheter between hemodialysis sessions, to decrease the risk of thrombosis and catheter malfunction, is unknown. The Prevention of Catheter Lumen Occlusion with rt-PA versus Heparin (PreCLOT) study will determine if use of weekly rt-PA, compared to regular heparin, as a catheter locking solution, will decrease the risk of catheter malfunction. METHODS/DESIGN: The study population will consist of patients requiring chronic hemodialysis thrice weekly who are dialyzed with a newly inserted permanent dual-lumen central venous catheter. Patients randomized to the treatment arm will receive rt-PA 1 mg per lumen once per week, with heparin 5,000 units per ml as a catheter locking solution for the remaining two sessions. Patients randomized to the control arm will receive heparin 5,000 units per ml as a catheter locking solution after each dialysis session. The study treatment period will be six months, with 340 patients to be recruited from 14 sites across Canada. The primary outcome will be catheter malfunction, based on mean blood flow parameters while on hemodialysis, with a secondary outcome of catheter-related bacteremia. A cost-effectiveness analysis will be undertaken to assess the cost of maintaining a catheter using rt-PA as a locking solution, compared to the use of heparin. DISCUSSION: Results from this study will determine if use of weekly rt-PA, compared to heparin, will decrease catheter malfunction, as well as assess the cost-effectiveness of these locking solutions.

Generalized seizure and toxic epidermal necrolysis following levofloxacin exposure.

OBJECTIVE: To report the case of a ciprofloxacin-allergic patient who developed a generalized tonic-clonic seizure and toxic epidermal necrolysis (TEN) following a single dose of levofloxacin. CASE SUMMARY: An 87-year-old white woman was admitted to the hospital following a transient episode of unresponsiveness that had been accompanied by flailing of her limbs. Approximately 4 hours earlier, she had developed a pruritic rash on her trunk and limbs, and 3 hours before this had taken a first dose of levofloxacin. The fluoroquinolone had been prescribed for treatment of an upper respiratory tract infection. She had developed a skin rash approximately 3 years earlier following ciprofloxacin prescribed for a urinary tract infection. On admission, the patient had a normal neurologic examination. She was mildly hypomagnesemic (serum magnesium 1.7 mg/dL), with no other electrolyte imbalances present. Skin biopsy confirmed TEN. The lesions progressed to involve 30% of the body surface area and were managed with polymyxin B and gramicidin cream. Levofloxacin was discontinued on admission, and no anticonvulsants were prescribed. The woman remained seizure-free at discharge one week later. DISCUSSION: Generalized tonic-clonic seizures are a rare complication of levofloxacin therapy. TEN following levofloxacin use has, to our knowledge, as of March 28, 2005, been previously reported only once. The seizure and TEN were probably induced by levofloxacin as corroborated by the Naranjo probability scale. We believe that the previous adverse dermatologic reaction to ciprofloxacin sensitized our patient to levofloxacin. CONCLUSIONS: These rare adverse reactions to levofloxacin, involving disparate organ systems, can occur simultaneously. A previous dematologic adverse reaction to a fluoroquinolone can sensitize a patient to more severe adverse reactions (with onset after only a single dose of the subsequent fluoroquinolone). Further fluoroquinolone use should be avoided in such patients.