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Etiology

Risk for contrast media-induced nephrotoxicity was low for both high and low-contrast media

ACP J Club. 1992 July-Aug;117:29. doi:10.7326/ACPJC-1992-117-1-029


Source Citation

Moore RD, Steinberg EP, Powe NR, et al. Nephrotoxicity of high-osmolality versus low-osmolality contrast media: randomized clinical trial. Radiology. 1992 Mar;182: 649-55.


Abstract

Objective

To determine the rate of and risk factors for contrast media-induced nephrotoxicity when using low-osmolality (LOM) or high-osmolality (HOM) contrast media.

Design

Randomized double-blind trial.

Setting

Radiology department at a university medical center in the United States.

Patients

929 patients having angiocardiography (n = 430) or contrast-enhanced body computed tomography (CT) (n = 499) who were hospitalized and ≥ 18 years old were studied. Patients having CT had also met ≥ 1 of the following criteria: age ≥ 60 years; serum creatinine level, 130 µmol/L to < 310 µmol/L; or presence of diabetes, multiple myeloma, nephrotic syndrome, hepatitis, cirrhosis, or hemoglobinopathy (except sickle cell disease). Exclusion criteria included previous reaction to contrast media; sickle cell disease; or contrast medium administered in the 72 hours before, or expected to be administered in the 48 hours after, catheterization or CT. Eligible patients were randomly allocated to receive either LOM or HOM.

Assessment of risk factors

Demographic and clinical data were collected from medical charts at patient enrollment.

Main outcome measure

Nephrotoxicity, defined as an increase in serum creatinine level of more than both 33% and 40 µmol/L above the baseline, within 48 hours of the radiologic procedure, and judged attributable to the contrast medium by a blinded panel. Logistic regression was used for multivariate analysis of risk factors.

Main results

Nephrotoxicity developed in 26 patients (3%): 13 of 479 (3%) who received LOM and 13 of 450 (3%) who received HOM (relative risk [RR] 1.06, P = 0.87). Patients had an increased risk for nephrotoxicity if they had had angiocardiography (RR 3.44, 95% CI 1.25 to 6.79), had pre-existing renal insufficiency (RR 3.06, CI 1.29 to 5.41), had insulin-dependent diabetes mellitus (RR 3.06, CI 1.19 to 7.80), or received furosemide (RR 2.92, CI 1.25 to 6.79). After adjusting for these factors, the type of contrast medium was not associated with the development of nephrotoxicity. A trend toward interaction between contrast-medium type and pre-existing renal insufficiency was found.

Conclusions

The frequencies of nephrotoxicity associated with HOM and LOM were similar and low. The factors that increased the risk for nephrotoxicity with either type of contrast medium were insulin-dependent diabetes mellitus, pre-existing renal insufficiency, furosemide use, and having angiocardiography.

Source of funding: In part, Sanofi Winthrop.

Address for article reprint: Dr. R.D. Moore, Department of Medicine, The Johns Hopkins University School of Medicine, 1830 East Monument Street, Room 8059, Baltimore, MD 21205, USA.


Commentary

Whether low-osmolality contrast media are less nephrotoxic than conventional high-osmolality media is unclear despite at least 19 randomized controlled trials (1). Moore and colleagues overcame many methodologic deficiencies of earlier trials by doing a double-blinded randomized trial with an appropriate sample size calculation and by limiting the study to patients with at least 1 risk factor for contrast-induced nephrotoxicity. They found no statistically significant difference in nephrotoxicity between the 2 types of contrast media. Patients with pre-existing renal insufficiency tended to have higher rates of nephrotoxicity from the high- compared with the low-osmolality media, a finding similar to that of a previous study (2).

Some problems limit generalization of these results. First, the rate of nephrotoxicity in the high-osmolality group was about half that expected from previous studies. Thus, their power to detect a difference in rates of nephrotoxicity was lower than intended. A second limitation is incomplete follow-up: One third of patients had serum creatinine measured at 24 hours but not at 48 hours after the procedure. Among those who did develop renal toxicity at 48 hours, half would have been undetected at 24 hours post-procedure. However, the low rates of nephrotoxicity (about 4% in both groups with complete follow-up) is a clinically important finding.

This study adds to a growing body of literature showing few differences in toxicity between the 2 types of contrast media except, perhaps, in patients with renal insufficiency. Pending further trials, physicians may wish to target the use of low-osmolality contrast media for groups with higher risk.

Thomas G. Tape, MD
University of Nebraska Medical CenterOmaha, Nebraska, USA

Thomas G. Tape, MD
University of Nebraska Medical Center
Omaha, Nebraska, USA


References

1. Kinnison ML, Powe NR, Steinberg EP. Results of randomized controlled trials of low- versus high-osmolality contrast media. Radiology. 1989;170:381-9.

2. Harris KG, Smith TP, Cragg AH, Lemke JH. Nephrotoxicity from contrast material in renal insufficiency: ionic versus nonionic agents. Radiology. 1991;179:849-52.