Obstructive spirometry pattern and the risk of chronic kidney disease: analysis from the community-based prospective Ansan-Ansung cohort in Korea

OBJECTIVE: There have been limited studies on the relationship between obstructive spirometry pattern and the development of chronic kidney disease (CKD). We investigated the association between obstructive spirometry pattern and incident CKD development in a large-scale prospective cohort study. METHODS: We reviewed the data of 7960 non-CKD adults aged 40–69 years who participated in the Ansung-Ansan cohort, a prospective community-based cohort study. Prebronchodilation results for the ratio of forced expiratory volume per 1 s (FEV1) to forced vital capacity (FVC) were used as the primary exposure. The primary outcome was incident CKD, defined as the first event of an estimated glomerular filtration rate <60 mL/min/1.73 m(2). HRs and 95% CIs were calculated using multivariate Cox proportional hazard regression analysis. RESULTS: Over a mean follow-up period of 11.7 years, incident CKD developed in 511 subjects (6.4%). An increase of 0.1 in FEV1/FVC was associated with a decreased risk of incident CKD (HR 0.76, 95% CI 0.68 to 0.84, p<0.001). Compared with the fourth quartile, the HR (95 % CI) of the first quartile of FEV1/FVC ratio was 1.81 (1.39 to 2.36, p<0.001). In the restricted cubic spline curve, the renal hazard associated with a decreased FEV1/FVC ratio was evident at FEV1/FVC values <0.80, showing a U-shaped relationship. In subgroup analysis, the renal hazard associated with a decreased FEV1/FVC ratio was particularly evident in people without metabolic syndrome (p for interaction=0.018). CONCLUSION: Decreased FEV1/FVC ratio was independently associated with an increased risk of incident CKD development, particularly in people without metabolic syndrome. Future studies need to be conducted to confirm these results.