Harmonizing acute and chronic kidney disease definition and classification: report of a Kidney Disease: Improving Global Outcomes (KDIGO) Consensus Conference

Kidney disease is an important public health problem. Both acute kidney injury (AKI) and chronic have been well defined classified, leading to improved research efforts subsequent management strategies recommendations. For those patients with abnormalities in function and/or structure who meet neither the definition of AKI nor disease, there remains a gap research, care, guidance. The term diseases disorders, abbreviated (AKD), has introduced as construct address this. To expand harmonize existing definitions ultimately better inform clinical Disease: Improving Global Outcomes (KDIGO) organized consensus workshop. Multiple invitees from around globe, representing both researchers experts, met virtually examine data, discuss key concepts related AKD. Despite some remaining unresolved questions, conference attendees reached general on classification AKD, strategies, priorities. AKD by implications for duration ≤3 months. may include AKI, but, more importantly, also includes that are not severe or develop over period >7 days. cause(s) should be sought, functional structural parameters. Management currently based empirical considerations. A robust agenda enable refinement validation systems, thus testing interventions proposed. In August 2020, convened Consensus Conference need (AKD) (CKD) definitions, recognition concept different (AKI), acknowledged understood. participants series plenary, discussion, closing sessions. Data were presented, interpretations debated, discussion groups focused 3 goals conference:(i)to revisit refine classifications improve understanding describe relationships between CKD;(ii)to delineate propose AKD; and(iii)to identify areas improvements practice health. Herein, we background, rationale, outputs deliberations. last 2 decades, classified CKD established standard staging systems both. 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What studies confirm risks AKD.Table 1AKD populationsStudyClinical areaNFollow-upAKD phenotypeMortalityIncident CKDXiao al., 20209Xiao ScholarHospitalized patients255690 dAKD AKIHR, 1.98 CI, 1.43–2.75)Nagata 202110Nagata patients75823600 6.69 5.0–8.94)Hsu 202011Hsu ScholarECMO168Up yrAKD 2.58 1.27–5.23)Mizuguchi 201812Mizuguchi ScholarBypass surgery10,234Up 8 vs. AKD15.9% 2.9%AKD CKD47.0% 19.3%Cho 202113Cho ScholarValvular surgery11901 AKDOR, 16.8 8.2–34.2)Matsuura 202014Matsuura ScholarCardiac surgery360590 dAKDHR, 63.0 27.9–180.6)Chen 202015Chen ScholarCoronary care2695 AKD22.7% 14.2%; P = 0.083Kofman al, 201916Kofman ScholarSTEMI22590 2.42 1.52–3.92)Long 201917Long ScholarPostsurgical2520Median, 3.4 yr (IQR, 1.2–7.1 yr)AKD AKIOR, 2.4 1.85–3.12)OR, 1.5 1.29–1.75)Tonon 202118Tonon ScholarLiver disease2725 AKD65.2% 11.2%13.8% 2.1%; < 0.001Mima 201919Mima ScholarStem transplant108100 dAKD29.4% 20.2%; 0.409AKD, injury; disease; interval; ECMO, oxygenation; HR, ratio; IQR, interquartile range; OR, odds STEMI, ST-segment–elevation infarction.All HRs ORs covariates. 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Community-acquired likely often goes undetected We broader “kidney disorders” (KD) Thus, can distinguished duration, harmonized under KD. “acute” defines condition sudden onset short-lived reversible; contrast, “chronic” refers subset consistent guideline.2Kidney abnormality increase SCr UO, intervals 6 hours 7 does damage, sediment proteinuria, cases UO less develops rapidly where exist gaps time, defining incorporated dovetail rationale modeling decrease GFR SCr, described detail appendices guideline. Figure 4 describes conceptual model continuum Various examples trajectories (functional criteria) depicted 5. Similar damage. By definition, lasts If resolution occurs, it must After months, most having they Patients meeting Scholar,11Hsu Scholar,13Cho Scholar,14Matsuura Scholar,16Kofman Scholar,22Sawhney 5 numerous possible trajectories, settings.23Kellum J.A. Sileanu F.E. Bihorac al.Recovery injury.Am Respir Crit Care Med. 2017; 195: 784-791Crossref (153) Previously, clinicians viewed discrete event resolves reaches steady Current recommendations event, even if recovered. episodes illness (or multiple illnesses), individual.23Kellum resolves, still workgroup believed arbitrary time-based days, proposed Disease Quality Initiative (ADQI),24Chawla L.S. Bellomo recovery: (ADQI) 16 Workgroup.Nat Rev 13: 241-257Crossref (481) warrants additional consideration, deferred next updating group. Until then, ambiguity remain about appropriate nomenclature episode current framework. Markers precede magnitude “implications health.” Using allows harmonization Recently, ADQI schema staging25Ostermann Zarbock Goldstein al.Recommendations Conference: statement.JAMA 3e2019209Crossref (52) Research underway qualify purpose. Possibly, neutrophil gelatinase-associated lipocalin [NGAL] molecule-1 [KIM-1]) hematuria, red blood casts origin, abnormalities) useful further categorizing depending underlying cause. Identification implementation cause-specific therapy. recommends when recognizes multifactorial. levels (cause, CGA many specify system time. differentiates (either Like necessary acknowledge entities because considerations differ 2).2Kidney Severity irrespective drives prognostic portend worse outcomes. Staging trial end points. principles (relative level CKD)2Kidney Scholar; therefore, combining them problematic. transition AKI-based CKD-based considered questions regarding AKD:•Can use staging?•Is AKI? When become AKI?•Should staging? so, when? ICU, intensive unit; KDIGO, Outcomes; KRT, replacement Workgroup