Preserved ratio impaired spirometry, airflow obstruction, and their trajectories in relationship to chronic kidney disease: a prospective cohort study

Abstract

Spirometry findings, such as restrictive spirometry and airflow obstruction, are associated with renal outcomes. Effects of spirometry findings such as preserved ratio impaired spirometry (PRISm) and its trajectories on renal outcomes are unclear. This study aimed to investigate the impact of baseline and trajectories of spirometry findings on future chronic kidney disease (CKD) events. This UK Biobank cohort study included participants with CKD who underwent spirometry at baseline (2006-2010). Lung function trajectories were determined using baseline and follow-up spirometry (2014-2020). Cox proportional hazards multivariate regression analysis was used to analyze the association between lung function and the incident CKD. In the baseline analysis (n = 282,354), fully adjusted hazard ratios (HRs) for PRISm participants (vs. normal spirometry) were 1.20 (1.07-1.34) for CKD and 1.51 (1.04-2.19) for end-stage renal disease (ESRD). Over an average 13.8-year follow-up period, 789 participants developed CKD. Trajectory analysis revealed higher CKD incidence with persistent AO (HR = 1.47(1.03-2.12)) and PRISm (HR = 1.28(0.88-1.88)) compared to normal lung function. Transitioning from AO to PRISm was associated with lower CKD incidence (HR = 0.27(0.08-0.93)). Recovery of normal lung function from AO could avert 16% of CKD cases. Our study indicated that baseline PRISm and airflow obstruction are associated with higher risk of incident CKD. Moreover, those with persistent AO findings had a higher risk of CKD incidence. These findings underscore the complex link between spirometry findings and renal outcomes and highlight the importance of considering respiratory and renal health in clinical assessments.

Keywords: Airflow obstruction; CKD incidence; Lung function; Preserved ratio impaired spirometry.

Fig. 1

Participant Study Progress in a Flowchart. CKD (Chronic kidney disease), ESRD (End-stage renal disease), AHI (Annual household income), BMI (Body mass index).

Fig. 2

Association of FEV₁% predicted and FVC% predicted with incident CKD using a restricted cubic spline regression; FEV₁, Forced expiratory volume in 1 s; FVC, Forced vital capacity; HR, Hazard ratio; CKD, Chronic kidney disease; In each model, potential confounders are the same as in model 3.

Fig. 3

Lung function trajectories from baseline to follow-up; PRISm, Preserved ratio impaired spirometry; AO, Airflow obstruction.

Fig. 4

Cumulative incidence curve for Cox models. Normal-Normal: Normal lung function at baseline and follow-up; Normal-PRISm: Normal lung function at baseline and PRISm at follow-up; Normal-AO: Normal lung function at baseline and airflow obstruction at follow-up; PRISm-Normal: PRISm at baseline and normal lung function at follow-up; PRISm-PRISm: PRISm at baseline and follow-up; PRISm-AO: PRISm at baseline and airflow obstruction at follow-up; AO-Normal: Airflow obstruction at baseline and normal lung function at follow-up; AO-PRISm: Airflow obstruction at baseline and PRISm at follow-up; AO-AO: Airflow obstruction at baseline and follow-up; CKD: Chronic CKD.