NEW YORK (Reuters Health) – Sodium bicarbonate isn’t any more effective than sodium chloride at preventing contrast-induced nephropathy (CIN) in patients with diabetic nephropathy, according to a new study.
The findings are in contrast to some previous studies that have shown a benefit to hydrating patients with sodium bicarbonate in those without diabetes. Other studies, however, have also suggested no difference between the two at preventing CIN.
Researchers led by Dr. Seung-Whan Lee of the University of Ulsan College of Medicine in Seoul randomly assigned 382 patients with both diabetes and renal disease to receive either sodium chloride or sodium bicarbonate, along with N-acetylcysteine (NAC), before an elective coronary or endovascular angiography or intervention.
Sodium bicarbonate (154 mEq/L) was infused at 3 ml/kg/hr beginning 1 hour before the contrast medium was injected, then lowered to 1 ml/kg/hr during the procedure until six hours after its completion. Sodium chloride was administered at a 0.9% concentration at 1 ml/kg/hr for 12 hours before and after the procedure. Patients with low left ventricular ejection fraction (< 45%) had their infusion rates cut to 0.5 ml/kg/hr in both groups.
All patients also were treated with 1,200mg oral NAC two times a day for two days, starting the day before the procedure.
Serum creatinine concentrations were measured at baseline and again 1 and 2 days after the procedure. CIN was defined as an increase in serum creatinine > 25% or an absolute increase in serum creatinine >/= 0.5 mg/dl.
Study participants themselves were not aware of whether they were treated with sodium chloride or sodium bicarbonate, but investigators were not blinded to drug assignments.
Patients were a median 68 years old with a median baseline estimated glomerular filtration of 46 ml/min/1.73 m2.
In the 48 hours following contrast exposure, rates of CIN were 5.3% in the sodium chloride group, compared to 9.0% in the sodium bicarbonate group (P = 0.17). Hemodialysis was required in 1.1% of the sodium chloride group and 2.1% of the sodium bicarbonate group (P = 0.69).
At six months follow-up, mortality rates were 1.1% in the sodium chloride group and 3.1% in patients that received sodium bicarbonate (P = 0.45). Cumulative dialysis rates were 1.6% among sodium chloride patients and 5.2% in sodium bicarbonate patients (P = 0.053). There were no cases of heart attack or stroke in either group.
“Our results and those of previous studies indicate that sodium bicarbonate may not be synergistic with NAC in the prevention of CIN,” the authors wrote in The American Journal of Cardiology.
In a multiple logistic regression analysis, CIN was linked to contrast volume (OR = 1.066, 95% CI: 1.027-1.106, p = 0.0008 per 10ml increase), left ventricular ejection fraction (OR = 1.052, 95% CI: 1.016-1.092, p = 0.0047 per 1-point decrease), and baseline creatinine (OR = 1.211, 95% CI: 1.132-1.295, p < 0.0001 per 0.1 mg/dl increase).
Median intravenous hydration volume was larger in patients that received sodium chloride (120 ml) compared to those that received sodium bicarbonate (113 ml), leading the authors to conclude that “intravenous infusion of sodium chloride still plays a major role in the prevention of CIN.”
Am J Cardiol
