Lung function change and quantitative computed tomography measurements are associated with prospective frailty.

BACKGROUND

Frailty, a state of reduced physiologic reserve, is associated with comorbid lung disease. Its relationship with lung function change over time and with lung computed tomography (CT) measurements is less clear.

METHODS

COPDGene, a multicentre cohort study, enrolled adults aged 45-80 years with a smoking history of a minimum of 10 pack-years. This study included participants with normal baseline 6-min walk distance (6MWD), spirometry at all three site visits and frailty assessment. The primary exposures were baseline quantitative CT measurements (airway wall thickening (Pi10), log (% emphysema), pulmonary artery (PA) enlargement and the ratio of pulmonary blood volume in vessels with a cross-sectional area <5 mm2 to the total blood vessel volume (BV5/TBV)) and spirometric decline over the 10-year study period. The primary outcomes were frailty and prefrailty at the 10-year follow-up (defined using a modified Fried Frailty Phenotype). Secondary analyses evaluated associations between inflammatory markers and frailty and for mediation of these associations by spirometric decline.

RESULTS

Of 2354 participants, 1200 (51%) were prefrail and 297 (13%) were frail at the 10-year follow-up. Baseline Pi10, log (% emphysema) and PA enlargement were significantly associated with increased odds of frailty (adjusted ORs, respectively: 1.52 (95% CI 1.30-1.77; p<0.001), 1.38 (95% CI 1.14-1.67; p<0.001) and 2.49 (95% CI 1.41-4.41; p=0.002)), as was lower BV5/TBV, an indicator of pulmonary vascular pruning (OR 0.59, 95% CI 0.48-0.72; p<0.001). Forced expiratory volume in 1 s (FEV1) decline was associated with increased odds of frailty (OR 1.47 (95% CI 1.30-1.65; p<0.001) per 1%-per-year drop). White blood cell count (WBC) and neutrophil to lymphocyte (N:L) ratio were associated with frailty; this was partially mediated by spirometric decline.

CONCLUSION

In a population with a cigarette smoking history, lung function decline and CT measurements were associated with prospective frailty risk.