Lung function impairment and lower spirometry parameters are associated with an increased risk for nonfatal and fatal cardiovascular disease (CVD) outcomes after adjustment for the predicted 10-year CVD risk score, according to study findings published in Thorax.
Researchers analyzed the predictive discrimination of CVD risk prediction models using lung function measures, using data from the UK Biobank that included individuals aged 37 to 73 years from 22 assessment centers in England, Wales, and Scotland from 2006 to 2010.
Participants had valid spirometry data and were without CVD at baseline. The lung function parameters evaluated included forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), peak expiratory flow (PEF), and FEV1/FVC ratio; chronic respiratory disease status at baseline was included as a new predictor.
The 3 main outcomes were (1) composite Cardiovascular Risk Score (QRISK3) CVD events; (2) composite American College of Cardiology/American Heart Association (ACC/AHA) CVD events; and (3) fatal European Systematic Coronary Risk Evaluation (SCORE) CVD events.
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FEV1 and FVC could serve as risk factors in the identification of high-risk individuals with composite and fatal CVD events and be a target for primary prevention and treatment.
Participants were followed until the first hospitalization for nonfatal CVD, death, loss to follow-up, or end of follow-up.
Among the 308,415 individuals in the database without baseline CVD and with complete data on covariates, 21,885 had QRISK3 composite CVD events, 12,843 had ACC/AHA composite CVD events, and 2987 had SCORE fatal CVD events during a median follow-up of 12.5 years. The analysis included 142,304 (46.1%) male individuals, and the mean (SD) age was 56.15 (8.05) years. The mean FVC, FEV1, PEF, and FEV1/FVC measures were 3.76 (1.00) L, 2.84 (0.79) L, 414.86 (125.83) L/ min, and 0.76 (0.07), respectively.
Associations of spirometry parameters with fatal and nonfatal CVD were reversed L-shaped, according to restricted cubic spline model findings.
Patients with chronic respiratory diseases had a 15% (95% CI, 11%-19%) increased risk for composite QRISK3 CVD; a 15% increased risk for composite ACC/AHA CVD (95% CI, 9%-21%); and a 28% (95% CI, 16%-42%) increased risk for a fatal SCORE CVD (after adjustment for predicted individual risks based on the original prediction models).
Restrictive and obstructive impairment were associated with hazard ratios (HRs) of 2.20 and 1.93, respectively, for fatal SCORE CVD compared with normal spirometry, after adjustment for age and sex. The effect sizes were attenuated for restrictive impairment (adjusted HR, 1.84; 95% CI, 1.65-2.06) and obstructive impairment (adjusted HR, 1.72; 95% CI, 1.55-1.90), after adjustment for predicted individual CVD risk with use of the original SCORE prediction model. Comparable associations occurred for composite ACC/AHA CVD and composite QRISK3 CVD, and the effect sizes were greater for fatal SCORE CVD outcomes. Significant interactions were found for chronic respiratory disease status, lung function impairment, and sex for composite QRISK3 CVD and composite ACC/AHA CVD.
In the original models, conventional risk factors resulted in a C-statistic of 0.7385 composite QRISK3 CVD, a C-statistic of 0.7303 composite ACC/AHA CVD, and a C-statistic of 0.7969 fatal SCORE CVD. All lung function measures resulted in significant improvement in discrimination, with the greatest improvement occurring for nonlinear FEV1 (C-statistic change: +0.0018 for composite QRISK3 CVD, +0.0033 for composite ACC/AHA CVD) or nonlinear FEV1 percent predicted (+0.0065 for fatal SCORE CVD).
In citing study limitations, the researchers noted that participants in the UK Biobank were healthier than the general population and that better performance of additional prediction value likely occurred in the general population. Also, secular trends in lung function were not accessible and no external validation was performed. “FEV1 and FVC could serve as risk factors in the identification of high-risk individuals with composite and fatal CVD events and be a target for primary prevention and treatment,” the study authors stated.
