Systemic sclerosis-associated interstitial pneumonia: evaluation of pulmonary function over a five-year period

Objective: To evaluate alterations in pulmonary function in patients with systemic sclerosis-associated interstitial pneumonia over a five-year period. Methods: This was a longitudinal study involving 35 nonsmoking patients with systemic sclerosis and without a history of lung disease. At the first evaluation, performed at the time of the diagnosis of interstitial pneumonia, the patients were submitted to HRCT, spirometry, and measurement of DLCO. The patients were subdivided into two groups by the presence or absence of honeycombing on the HRCT scans. Approximately five years after the first evaluation, the patients were submitted to spirometry and measurement of DLCO only. Results: Of the 35 patients, 34 were women. The mean age was 47.6 years. The mean time between the two evaluations was 60.9 months. Honeycombing was detected on the HRCT scans in 17 patients. In the sample as a whole, five years after the diagnosis, FVC, FEV1, and DLCO significantly decreased (81.3 +/- 18.2% vs. 72.1 +/- 22.2%; 79.9 +/- 17.8% vs. 72.5 +/- 20.6%; and 74.0 +/- 20.5% vs. 60.7 +/- 26.8%, respectively; p = 0.0001 for all), and the FEV1/FVC ratio significantly increased (98.5 +/- 7.2% vs. 101.9 +/- 7.8%; p = 0.008). In the same period, FVC, FEV1, and DLCO values were significantly lower in the patients with honeycombing on the HRCT scans than in those without (p = 0.0001). Conclusions: In systemic sclerosis-associated interstitial lung disease, the detection of honeycombing on HRCT is crucial to predicting accelerated worsening of pulmonary function.