Smoking, Smoking Cessation, and Progression of Chronic Kidney Disease: Results from KNOW-CKD Study

Sangmi Lee, Shinchan Kang, Young Su Joo, Changhyun Lee, Ki Heon Nam, Hae Ryong Yun, Jung Tak Park, Tae Ik Chang, Tae Hyun Yoo, Soo Wan Kim, Kook Hwan Oh, Yeong Hoon Kim, Sue K. Park, Shin Wook Kang, Kyu Hun Choi, Curie Ahn, Seung Hyeok Han

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)


Introduction: In patients with chronic kidney disease (CKD), studies investigating the association between smoking and deterioration of kidney function are scarce. Aims and Methods: We analyzed data for 1,951 patients with an estimated glomerular filtration rate (EGFR) ≥15 mL/min/1.73 m2 enrolled in the Korean cohort study for Outcome in patients With Chronic Kidney Disease (KNOW-CKD) from 2011 to 2016. Patients were categorized by smoking load. Primary outcome was a composite of a ≥50% reduction in EGFR, initiation of dialysis, or kidney transplantation. Results: There were 967 never-smokers and 369, 276, and 339 smokers who smoked <15, 15 to 29, ≥30 pack-years, respectively. During a mean follow-up of 3.0 years, the incidence rates (95% confidence interval [CI]) of the primary outcome were 54.3 (46.4-63.5), 46.9 (35.9-61.4), 69.2 (52.9-90.6), and 76.3 (60.7-96.0) events per 1,000 person-yr in never-, <15, 15 to 29, and ≥30 pack-year smokers. In cause-specific hazard model after adjustment of confounding factors, smokers were associated with 1.09 (0.73-1.63), 1.48 (1.00-2.18), and 1.94 (1.35-2.77) fold increased risk (95% CI) of primary outcome in <15, 15-29, and ≥30 pack-year smokers compared with never-smokers. The association of longer smoking duration with higher risk of CKD progression was evident particularly in patients with EGFR < 45 mL/min/1.73 m2 and proteinuria ≥ 1.0 g/g. In contrast, the risk of adverse kidney outcome decreased with longer smoking-free periods among former-smokers. Conclusions: These findings suggest potentially harmful effects of the degree of exposure to smoking on the progression of CKD. Implications: Among patients with CKD, there has been lack of studies on the association between smoking and CKD progression and studies to date have yielded conflicting results. In this prospective cohort study involving Korean CKD patients, smoking was associated with significantly higher risk of worsening kidney function. Furthermore, the risk of adverse kidney outcome was incrementally higher as smoking pack-years were higher. As the duration of smoking cessation increased, the hazard ratios for adverse kidney outcome were attenuated, suggesting that quitting smoking may be a modifiable factor to delay CKD progression.

Original languageEnglish
Pages (from-to)92-98
Number of pages7
JournalNicotine and Tobacco Research
Issue number1
Publication statusPublished - 2021 Jan 1

Bibliographical note

Publisher Copyright:
© 2020 The Author(s) 2020. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved.

All Science Journal Classification (ASJC) codes

  • General Medicine


Dive into the research topics of 'Smoking, Smoking Cessation, and Progression of Chronic Kidney Disease: Results from KNOW-CKD Study'. Together they form a unique fingerprint.

Cite this