Aspirin and clonidine in non-cardiac surgery: acute kidney injury substudy protocol of the Perioperative Ischaemic Evaluation (POISE) 2 randomised controlled trial

Antiplatelet agents for chronic kidney disease

BACKGROUND

Antiplatelet agents are widely used to prevent cardiovascular events. The risks and benefits of antiplatelet agents may be different in people with chronic kidney disease (CKD) for whom occlusive atherosclerotic events are less prevalent, and bleeding hazards might be increased. This is an update of a review first published in 2013.

OBJECTIVES

To evaluate the benefits and harms of antiplatelet agents in people with any form of CKD, including those with CKD not receiving renal replacement therapy, patients receiving any form of dialysis, and kidney transplant recipients.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 13 July 2021 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

We selected randomised controlled trials of any antiplatelet agents versus placebo or no treatment, or direct head-to-head antiplatelet agent studies in people with CKD. Studies were included if they enrolled participants with CKD, or included people in broader at-risk populations in which data for subgroups with CKD could be disaggregated.

DATA COLLECTION AND ANALYSIS

Four authors independently extracted data from primary study reports and any available supplementary information for study population, interventions, outcomes, and risks of bias. Risk ratios (RR) and 95% confidence intervals (CI) were calculated from numbers of events and numbers of participants at risk which were extracted from each included study. The reported RRs were extracted where crude event rates were not provided. Data were pooled using the random-effects model. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

We included 113 studies, enrolling 51,959 participants; 90 studies (40,597 CKD participants) compared an antiplatelet agent with placebo or no treatment, and 29 studies (11,805 CKD participants) directly compared one antiplatelet agent with another. Fifty-six new studies were added to this 2021 update. Seven studies originally excluded from the 2013 review were included, although they had a follow-up lower than two months. Random sequence generation and allocation concealment were at low risk of bias in 16 and 22 studies, respectively. Sixty-four studies reported low-risk methods for blinding of participants and investigators; outcome assessment was blinded in 41 studies. Forty-one studies were at low risk of attrition bias, 50 studies were at low risk of selective reporting bias, and 57 studies were at low risk of other potential sources of bias. Compared to placebo or no treatment, antiplatelet agents probably reduces myocardial infarction (18 studies, 15,289 participants: RR 0.88, 95% CI 0.79 to 0.99, I² = 0%; moderate certainty). Antiplatelet agents has uncertain effects on fatal or nonfatal stroke (12 studies, 10.382 participants: RR 1.01, 95% CI 0.64 to 1.59, I² = 37%; very low certainty) and may have little or no effect on death from any cause (35 studies, 18,241 participants: RR 0.94, 95 % CI 0.84 to 1.06, I² = 14%; low certainty). Antiplatelet therapy probably increases major bleeding in people with CKD and those treated with haemodialysis (HD) (29 studies, 16,194 participants: RR 1.35, 95% CI 1.10 to 1.65, I² = 12%; moderate certainty). In addition, antiplatelet therapy may increase minor bleeding in people with CKD and those treated with HD (21 studies, 13,218 participants: RR 1.55, 95% CI 1.27 to 1.90, I² = 58%; low certainty). Antiplatelet treatment may reduce early dialysis vascular access thrombosis (8 studies, 1525 participants) RR 0.52, 95% CI 0.38 to 0.70; low certainty). Antiplatelet agents may reduce doubling of serum creatinine in CKD (3 studies, 217 participants: RR 0.39, 95% CI 0.17 to 0.86, I² = 8%; low certainty). The treatment effects of antiplatelet agents on stroke, cardiovascular death, kidney failure, kidney transplant graft loss, transplant rejection, creatinine clearance, proteinuria, dialysis access failure, loss of primary unassisted patency, failure to attain suitability for dialysis, need of intervention and cardiovascular hospitalisation were uncertain. Limited data were available for direct head-to-head comparisons of antiplatelet drugs, including prasugrel, ticagrelor, different doses of clopidogrel, abciximab, defibrotide, sarpogrelate and beraprost.

AUTHORS' CONCLUSIONS

Antiplatelet agents probably reduced myocardial infarction and increased major bleeding, but do not appear to reduce all-cause and cardiovascular death among people with CKD and those treated with dialysis. The treatment effects of antiplatelet agents compared with each other are uncertain.

Effect of a Perioperative Hypotension-Avoidance Strategy Versus a Hypertension-Avoidance Strategy on the Risk of Acute Kidney Injury: A Clinical Research Protocol for a Substudy of the POISE-3 Randomized Clinical Trial

Background:

Most patients who take antihypertensive medications continue taking them on the morning of surgery and during the perioperative period. However, growing evidence suggests this practice may contribute to perioperative hypotension and a higher risk of complications. This protocol describes an acute kidney injury substudy of the Perioperative Ischemic Evaluation-3 (POISE-3) trial, which is testing the effect of a perioperative hypotension-avoidance strategy versus a hypertension-avoidance strategy in patients undergoing noncardiac surgery.

Objective:

To conduct a substudy of POISE-3 to determine whether a perioperative hypotension-avoidance strategy reduces the risk of acute kidney injury compared with a hypertension-avoidance strategy.

Design:

Randomized clinical trial with 1:1 randomization to the intervention (a perioperative hypotension-avoidance strategy) or control (a hypertension-avoidance strategy).

Intervention:

If the presurgery systolic blood pressure (SBP) is <130 mmHg, all antihypertensive medications are withheld on the morning of surgery. If the SBP is ≥130 mmHg, some medications (but not angiotensin receptor blockers [ACEIs], angiotensin receptor blockers [ARBs], or renin inhibitors) may be continued in a stepwise manner. During surgery, the patients’ mean arterial pressure (MAP) is maintained at ≥80 mmHg. During the first 48 hours after surgery, some antihypertensive medications (but not ACEIs, ARBs, or renin inhibitors) may be restarted in a stepwise manner if the SBP is ≥130 mmHg.

Control:

Patients receive their usual antihypertensive medications before and after surgery. The patients’ MAP is maintained at ≥60 mmHg from anesthetic induction until the end of surgery.

Setting:

Recruitment from 108 centers in 22 countries from 2018 to 2021.

Patients:

Patients (~6800) aged ≥45 years having noncardiac surgery who have or are at risk of atherosclerotic disease and who routinely take antihypertensive medications.

Measurements:

The primary outcome of the substudy is postoperative acute kidney injury, defined as an increase in serum creatinine concentration of either ≥26.5 μmol/L (≥0.3 mg/dL) within 48 hours of randomization or ≥50% within 7 days of randomization.

Methods:

The primary analysis (intention-to-treat) will examine the relative risk and 95% confidence interval of acute kidney injury in the intervention versus control group. We will repeat the primary analysis using alternative definitions of acute kidney injury and examine effect modification by preexisting chronic kidney disease, defined as a prerandomization estimated glomerular filtration rate <60 mL/min/1.73 m².

Results:

Substudy results will be analyzed in 2022.

Limitations:

It is not possible to mask patients or providers to the intervention; however, objective measures will be used to assess acute kidney injury.

Conclusions:

This substudy will provide generalizable estimates of the effect of a perioperative hypotension-avoidance strategy on the risk of acute kidney injury.

Effects of peri-operative nonsteroidal anti-inflammatory drugs on post-operative kidney function for adults with normal kidney function

BACKGROUND

Nonsteroidal anti-inflammatory drugs (NSAIDs) provide effective analgesia during the post-operative period but can cause acute kidney injury (AKI) when used peri-operatively (at or around the time of surgery). This is an update of a Cochrane review published in 2007.

OBJECTIVES

This review looked at the effect of NSAIDs used in the peri-operative period on post-operative kidney function in patients with normal kidney function.

SEARCH METHODS

We searched Cochrane Kidney and Transplant's Specialised Register to 4 January 2018 through contact with the Information Specialist using search terms relevant to this review. Studies in the Specialised Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

All randomised controlled trials (RCTs) and quasi-RCTs (RCTs in which allocation to treatment was obtained by alternation, use of alternate medical records, date of birth or other predictable methods) looking at the use of NSAIDs versus placebo for the treatment of post-operative pain in patients with normal kidney function were included.

DATA COLLECTION AND ANALYSIS

Data extraction was carried out independently by two authors as was assessment of risk of bias. Disagreements were resolved by a third author. Dichotomous outcomes are reported as relative risk (RR) and continuous outcomes as mean difference (MD) together with their 95% confidence intervals (CI). Meta-analyses were used to assess the outcomes of AKI, change in serum creatinine (SCr), urine output, renal replacement therapy (RRT), death (all causes) and length of hospital stay.

MAIN RESULTS

We identified 26 studies (8835 participants). Risk of bias was high in 17, unclear in 6and low in three studies. There was high risk of attrition bias in six studies.Only two studies measured AKI. The use of NSAIDs had uncertain effects on the incidence of AKI compared to placebo (7066 participants: RR 1.79, 95% CI 0.40 to 7.96; I2 = 59%; very low certainty evidence). One study was stopped early by the data monitoring committee due to increased rates of AKI in the NSAID group. Moreover, both of these studies were examining NSAIDs for indications other than analgesia and therefore utilised relatively low doses.Compared to placebo, NSAIDs may slightly increase serum SCr (15 studies, 794 participants: MD 3.23 μmol/L, 95% CI -0.80 to 7.26; I2 = 63%; low certainty evidence). Studies displayed moderate to high heterogeneity and had multiple exclusion criteria including age and so were not representative of patients undergoing surgery. Three of these studies excluded patients if their creatinine rose post-operatively.NSAIDs may make little or no difference to post-operative urine output compared to placebo (6 studies, 149 participants: SMD -0.02, 95% CI -0.31 to 0.27). No reliable conclusions could be drawn from these studies due to the differing units of measurements and measurement time points.It is uncertain whether NSAIDs leads to the need for RRT because the certainty of this evidence is very low (2 studies, 7056 participants: RR 1.57, 95% CI 0.49 to 5.07; I2 = 26%); there were few events and the results were inconsistent.It is uncertain whether NSAIDs lead to more deaths (2 studies, 312 participants: RR 1.44, 95% CI 0.19 to 11.12; I2 = 38%) or increased the length of hospital stay (3 studies, 410 participants: MD 0.12 days, 95% CI -0.48 to 0.72; I2 = 24%).

AUTHORS' CONCLUSIONS

Overall NSAIDs had uncertain effects on the risk of post-operative AKI, may slightly increase post-operative SCr, and it is uncertain whether NSAIDs lead to the need for RRT, death or increases the length of hospital stay. The available data therefore does not confirm the safety of NSAIDs in patients undergoing surgery. Further larger studies using the Kidney Disease Improving Global Outcomes definition for AKI including patients with co-morbidities are required to confirm these findings. .