The current standard of care for prevention of contrast-induced nephropathy (CIN) is volume expansion; however, randomized-controlled trials (RCTs) comparing interventions draw disparate conclusions. This may raise concerns about internal validity of the underlying studies. In other disease states, a high risk-of-bias (ROB) has been associated with exaggerated effect sizes, but such an evaluation is lacking for CIN prophylaxis. Ultimately, completion of this study will assist clinical pharmacists in selecting the most effective CIN prophylaxis intervention.
To determine if ROB is associated with larger effect sizes in RCTs investigating prophylactic interventions for contrast-induced nephropathy.
We searched PubMed and Embase to identify RCTs that evaluated renal outcomes for three CIN prophylactic treatments (intravenous [IV] normal saline, IV sodium bicarbonate, and/or IV or oral N-acetylcysteine) in patients undergoing procedures requiring contrast media. We assessed ROB using a critical appraisal tool from the Joanna Briggs Institute (JBI). We conducted title/abstract and full-text screening as well as data collection in duplicate. To examine potential publication bias and/or other small study effects, we plan to visually examine funnel plots and conduct Eggers’ tests, assuming that a sufficient number of trials is available. We will check for heterogeneity using an I2 test. Potential sources of heterogeneity, including population, intervention, and protocol differences, will also be examined in subgroup and sensitivity analyses. To test our central hypothesis that ROB is associated with exaggerated effect sizes, we will conduct univariable and multivariable random-effects meta-regressions to examine the impact of JBI ROB dimensions on the natural log of the effect sizes reported in each RCT.
Our search returned 1,984 results. After title and abstract screening, a total of 209 studies remained for full-text review. Final results will be presented including coefficients for the mean change in effect sizes associated with the various ROB domains.