Kidney Res Clin Pract 35 (2016) 192e193
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Letter and Reply
The association between acute kidney injury in renal infarction and progression to chronic kidney disease
To the Editor: Renal infarction (RI) is a rare condition resulting from the acute disruption of renal blood ﬂow in the renal arteries or their branches. Heart disease, renal artery injury, hypercoagulability, and idiopathic origins are the causes of renal infarction. Despite urokinase, heparin, warfarin, and antiplatelet treatment, RI can lead to acute kidney injury (AKI), chronic kidney disease (CKD), end-stage renal disease, and death [1e3]. In the previous issue of this journal, Yang et al  presented a retrospective single-center study for risk factors and outcome of RI. In their study, AKI was found in 34.8% of patients. Diabetes mellitus and high C-reactive protein were independent predictors for AKI on multivariate analysis. RI progressed to CKD in 27.4% of patients, and old age was an independent risk factor for CKD. Surprisingly, AKI history was inversely proportional to the development of CKD . In contrast, the previous large meta-analysis showed that patients with AKI had a higher risk for developing CKD (pooled adjusted hazard ratio, 8.8; 95% conﬁdence interval, 3.1e25.5) . Yang et al  explained that the inverse association between AKI and CKD progression probably resulted from wrong patient selection because the long-term analysis was conducted only from the patients who survived. They stated that excluded patients had higher incidence of AKI, diabetes mellitus and malignancy. These patients also had higher Charlson comorbidity index score and C-reactive protein level. In conclusion, Cox regression analyses of risk factors associated with the estimated glomerular ﬁltration rate decreasing to < 60 mL/min/1.73 m2 after 1 year in RI had selection bias . The authors may need to further analyze long-term outcomes of RI using not only CKD but also other composite outcomes such as death, increasing creatinine more than 2 times, or hospitalization.
Yun Kyu Oh Department of Internal Medicine, Seoul National University Boramae Medical Center, 20 Boramaero 5-gil, Dongjak-gu, Seoul, 07061, Korea E-mail address: [email protected]
Copyright © 2016. The Korean Society of Nephrology. Published by Elsevier. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/ by-nc-nd/4.0/).
References  Oh YK, Yang CW, Kim YL, Kang SW, Park CW, Kim YS, Lee EY, Han BG, Lee SH, Kim SH, Lee H, Lim CS: Clinical characteristics and outcomes of renal infarction. Am J Kidney Dis 67:243e250, 2016  Bae EJ, Hwang K, Jang HN, Kim MJ, Jeon DH, Kim HJ, Cho HS, Chang SH, Park DJ: A retrospective study of short- and long-term effects on renal function after acute renal infarction. Ren Fail 36: 1385e1389, 2014  Bourgault M, Grimbert P, Verret C, Pourrat J, Herody M, Halimi JM, Karras A, Amoura Z, Jourde-Chiche N, Izzedine H, François H, Boffa JJ, Hummel A, Bernadet-Monrozies P, Fouque D, CanouïPoitrine F, Lang P, Daugas E, Audard V: Acute renal infarction: a case series. Clin J Am Soc Nephrol 8:392e398, 2013  Yang J, Lee JY, Na YJ, Lim SY, Kim MG, Jo SK, Cho W: Risk factors and outcomes of acute renal infarction. Kidney Res Clin Pract 35:90e95, 2016  Coca SG, Singanamala S, Parikh CR: Chronic kidney disease after acute kidney injury: a systematic review and meta-analysis. Kidney Int 81:442e448, 2012
Available online 9 August 2016 http://dx.doi.org/10.1016/j.krcp.2016.08.001
Conﬂicts of interest The author has no conﬂicts of interest to declare.