Prognostic significance of surrogate measures for forced vital capacity in an elderly population

To evaluate whether measures easier to obtain than the FVC can substitute it as a prognostic marker in elderly people.

Prospective, observational study.

Community.

Outpatients (n = 1485) aged 73.4 years (SD: 6.2 range 65-98) enrolled in the Salute Respiratoria nell'Anziano (SaRA) study.

We calculated the risk for mortality associated with a reduction below 80% of the predicted FVC, of the forced expiratory volume at 6 seconds (FEV6), and of a surrogate measure for forced vital capacity (SFVC), defined as the largest volume exhaled in 2 forced maneuvers regardless of its duration and of the presence of plateau.

Among the 907 participants who attained the FVC, the mortality rate ratio (MRR) associated with having a low FVC, FEV6, and SFVC were 1.37 (95% CI: 0.91-2.00), 1.66 (95% CI: 1.15-2.36), and 1.28 (95% CI: 0.88-1.84), respectively. In those who could not obtain the FVC, mortality was more strongly associated with both low FEV6 (MRR: 3.02, 95% CI: 1.72-5.24) and low SFVC (MRR: 2.18; 95% CI: 1.53-3.10). The association between SFVC and mortality was present in the whole population, even after adjustment for age, gender, disability, mood, and cognitive status (MRR: 1.64; 95% CI: 1.29-2.09).

The SFVC provides similar prognostic information compared with the FVC, and is associated with increased mortality in the subgroup of patients not able to attain the FVC. This measure can make the respiratory assessment for prognostic purposes easier, especially in elderly patients who have a high prevalence of respiratory diseases, but frequently fail to perform an FVC maneuver complying with recommended standards.