Maximal inspiratory pressure predicts mortality in patients with chronic obstructive pulmonary disease in a five-year follow-up

Abstract

Introduction: The therapeutic modality for the treatment of COPD depends on the proper determination of all factors that may have an effect on the course and prognosis of the disease.

Aim: To assess the prognostic role of maximal inspiratory pressure (PImax) and a large group of lung function parameters in patients with COPD followed up over a period of five years.

Patients and methods: A cohort of 63 COPD patients (age 58.6 +/- 8.8 yrs, BMI 24.2 +/- 5.6, FEV1% = 35 +/- 14%, PImax = 52.3 +/- 19.0 cm H2O; x +/- S x) was recruited for a 5-year prospective study. Mortality was assessed as overall mortality. The independent predictors of survival were determined using the Cox proportional hazards model.

Results: The deceased patients (n = 32) had lower values of BMI, FEV1, DL(CO)/V(A)%, PaO2, PImax, and six-minute walking test (6MWT) and higher RV/TLC% (p < 0.05) than the survivors. The regression model included the following parameters: age, BMI, smoking history, FEV1, FVC, DL(CO)/V(A)%, lung hyperinflation (RV/TLC%), PImax, PaO2, PaCO2, hematocrit, mean pulmonary artery pressure (mPAP - Doppler echocardiography), symptoms (Anthonisen scale), dyspnea, comorbidity (Charlson index), frequency of exacerbations in the previous year, and the exercise capacity (6MWT). Statistical analysis indicated that PImax was an independent predictor of mortality (p = 0.005).

Conclusion: Low PImax was associated with greater overall mortality rate in this cohort of patients with COPD.