The first dedicated trial of aspirin to prevent heart attack and stroke in CKD has reported
The trial aimed to recruit more than 25,000 people. The pandemic left it with 4,633. That limits how much its results can tell us.
People with chronic kidney disease are at high cardiovascular risk. That makes aspirin for primary prevention a fair question. It also makes the answer hard. CKD raises bleeding risk too. And we cannot assume that the benefit seen after a heart attack or stroke applies before one.
Until now, the evidence came mostly from small CKD subgroups inside general-population trials. NICE called for a dedicated trial in 2014.² ATTACK set out to be that trial.
ATTACK ran through UK general practice. Practices searched their coded records for eligible patients. These were adults with CKD stages G1 to G4 and no history of cardiovascular disease. Practices then invited them to take part. The trial randomised people to aspirin 75 mg once daily or usual care. Treatment was open label. Assessors judged the endpoints without knowing who took aspirin.²
The main outcome was the time to a first major cardiovascular event. This meant a non-fatal MI, a non-fatal stroke or a cardiovascular death. Cardiovascular deaths from intracranial haemorrhage or other bleeding did not count towards it. Secondary outcomes included major bleeding and death from any cause.¹ ²
The trial needed 25,210 people to have enough statistical power. The COVID pandemic disrupted recruitment, and the trial switched to remote consultations. Between March 2019 and December 2023, the trial randomised 4,633 people: 2,317 to aspirin and 2,316 to usual care.¹ ²
The team presented the results at ASN Kidney Week on 23 October 2026. Over a mean follow-up of 3.1 years:¹
Major cardiovascular events: 56 (2.4%) with aspirin versus 76 (3.3%) without. Subdistribution hazard ratio (SHR) 0.73 (95% CI 0.52 to 1.03).
Major bleeds: 29 with aspirin versus 19 without. Of these, 10 and 9 respectively were intracranial. SHR 1.54 (95% CI 0.86 to 2.74).
Deaths: 124 (5.4%) with aspirin versus 113 (4.9%) without. HR 1.11 (95% CI 0.86 to 1.43).
The point estimate for cardiovascular events favoured aspirin. The confidence interval also included no effect. The bleeding estimate went the other way, again with wide uncertainty. Neither difference was statistically significant.
The investigators call the 27% reduction clinically meaningful but not statistically significant. The trial may have been too small to show an effect. But the findings are also consistent with no effect. They call the evidence inconclusive. They say the question needs further trials or a meta-analysis.¹
Hugh Gallagher, the chief investigator, said aspirin "may provide an overall net clinical benefit". But he added that the team "cannot be certain", because the trial was so much smaller than planned. Next, the team will combine its results with earlier studies. It is doing this with the Antithrombotic Trialists' Collaboration.³
The NIHR and the British Heart Foundation funded ATTACK. The results come from a congress presentation. There is no full peer-reviewed paper yet.
What does this mean in primary care?
ATTACK does not settle whether aspirin prevents a first cardiovascular event in CKD.
The estimates point to fewer cardiovascular events and more major bleeds with aspirin. Neither result reached statistical significance.
ATTACK recruited through UK general practice. Its findings speak directly to primary care. The pooled analysis is the one to watch.
Patients who ask can be told that the first dedicated trial has reported and did not give a clear answer.
The investigators link the recruitment shortfall to the COVID pandemic.
Intended for UK healthcare professionals only. This article reports on published clinical data and does not constitute prescribing advice.
References
Gallagher H, Fraser SD, Wilding S, et al. ATTACK (Aspirin To Target Arterial events in Chronic Kidney Disease): a multicentre randomised trial of aspirin vs. usual care for the primary prevention of cardiovascular events in patients with CKD. Abstract FR-OR100. American Society of Nephrology Kidney Week; 22 to 25 October 2026; Denver, CO. https://www.asn-online.org/education/kidneyweek/2026/program-abstract.aspx?controlId=4591892
Gallagher H, Dumbleton J, Maishman T, et al. Aspirin to target arterial events in chronic kidney disease (ATTACK): study protocol for a multicentre, prospective, randomised, open-label, blinded endpoint, parallel group trial of low-dose aspirin vs. standard care for the primary prevention of cardiovascular disease in people with chronic kidney disease. Trials. 2022;23:331. doi:10.1186/s13063-022-06132-z
American Society of Nephrology. Late breaking, high-impact clinical trials featured at Kidney Week 2026 explore new frontiers to improve kidney health. Press release, 23 October 2026. https://www.asn-online.org/about/press/releases/ASN_PR_20261023_2026KidneyWeekTrial.pdf (accessed October 2026)