Maintaining Normal Levels of Ionized Calcium during Citrate-Based Renal Replacement Therapy Is Associated with Stable Parathyroid Hormone Levels

TY - JOUR

T1 - Maintaining Normal Levels of Ionized Calcium during Citrate-Based Renal Replacement Therapy Is Associated with Stable Parathyroid Hormone Levels

AU - Raimundo, Mario

AU - Crichton, Siobhan

AU - Lei, Katie

AU - Sanderson, Barnaby

AU - Smith, John

AU - Brooks, John

AU - Ng, Josephine

AU - Smith, Joanna Lemmich

AU - McKenzie, Catherine

AU - Beale, Richard

AU - Dickie, Helen

AU - Ostermann, Marlies

PY - 2013/12

Y1 - 2013/12

N2 - Background/Aims: Citrate is an effective anticoagulant during continuous renal replacement therapy (CRRT). Previous studies showed raised parathyroid hormone (PTH) levels when aiming for serum ionized calcium [Ca-i] between 0.8 and 1.1 mmol/l. Our objective was to assess whether citrate-based CRRT with physiologic target systemic [Ca-i] between 1.12 and 1.20 mmol/l could maintain stable PTH levels. Methods: Measurement of intact PTH (PTHi) in 30 consecutive critically ill patients treated with citrate-based CRRT. Results: Thirty patients [mean age: 70.4 (SD 11.3) years; 56.7% males] were enrolled. Mean serum [Ca-i] was 1.16 mmol/l (SD 0.09), 1.13 mmol/l (SD 0.09), 1.17 mmol/l (SD 0.05) and 1.16 mmol/l (SD 0.04) at baseline, 12, 24 and 48 h, respectively (p = 0.29). Median PTHi levels (interquartile range) at baseline, 12, 24 and 48 h were 66.5 (43-111), 109 (59.5-151.5), 88.5 (47-133) and 85 pg/ml (53-140), respectively. The differences between baseline and 12 h and across all time points were statistically not significant (p = 0.16 and p = 0.49, respectively). In a mixed-effects model, each 0.1 mmol/l increase in serum [Ca-i] was associated with a 31.2% decrease in PTHi (p <0.001). Results were unchanged after adjustment for age, gender, magnesium, phosphate, arterial pH and time spent on CRRT. Conclusions: Maintaining systemic [Ca-i] within the physiologic range was associated with stable PTHi levels.

AB - Background/Aims: Citrate is an effective anticoagulant during continuous renal replacement therapy (CRRT). Previous studies showed raised parathyroid hormone (PTH) levels when aiming for serum ionized calcium [Ca-i] between 0.8 and 1.1 mmol/l. Our objective was to assess whether citrate-based CRRT with physiologic target systemic [Ca-i] between 1.12 and 1.20 mmol/l could maintain stable PTH levels. Methods: Measurement of intact PTH (PTHi) in 30 consecutive critically ill patients treated with citrate-based CRRT. Results: Thirty patients [mean age: 70.4 (SD 11.3) years; 56.7% males] were enrolled. Mean serum [Ca-i] was 1.16 mmol/l (SD 0.09), 1.13 mmol/l (SD 0.09), 1.17 mmol/l (SD 0.05) and 1.16 mmol/l (SD 0.04) at baseline, 12, 24 and 48 h, respectively (p = 0.29). Median PTHi levels (interquartile range) at baseline, 12, 24 and 48 h were 66.5 (43-111), 109 (59.5-151.5), 88.5 (47-133) and 85 pg/ml (53-140), respectively. The differences between baseline and 12 h and across all time points were statistically not significant (p = 0.16 and p = 0.49, respectively). In a mixed-effects model, each 0.1 mmol/l increase in serum [Ca-i] was associated with a 31.2% decrease in PTHi (p <0.001). Results were unchanged after adjustment for age, gender, magnesium, phosphate, arterial pH and time spent on CRRT. Conclusions: Maintaining systemic [Ca-i] within the physiologic range was associated with stable PTHi levels.

KW - Citrate

KW - Parathyroid hormone

KW - Continuous renal replacement therapy

KW - Acute kidney injury

KW - CRITICALLY-ILL PATIENTS

KW - CONTINUOUS VENOVENOUS HEMOFILTRATION

KW - HEPARIN ANTICOAGULATION

KW - REGIONAL CITRATE

KW - BONE-RESORPTION

KW - HEMODIAFILTRATION

KW - SECRETION

KW - SEVERITY

KW - SURVIVAL

U2 - 10.1159/000355860

DO - 10.1159/000355860

M3 - Article

SN - 1660-2110

VL - 124

SP - 124

EP - 131

JO - NEPHRON CLINICAL PRACTICE

JF - NEPHRON CLINICAL PRACTICE

IS - 1-2

ER -