A simple clinical decision rule may help predict interstitial lung disease (ILD) in patients with systemic sclerosis (SSc). The rule also may help estimate the prevalence of SSc-ILD.
Steele and colleagues gathered patient registry data and considered algorithms for the clinical decision rule based on lung auscultation, chest radiography (CXR), and percentage of predicted forced vital capacity (FVC). High-resolution CT (HRCT) scans were used to determine the algorithms' diagnostic properties.
Evidence of ILD was seen in 64% of the patients who had HRCT scans but in only 26% and 22% of those evaluated by physical examination and by CXR, respectively. The FVC of those who did not have HRCT was 8.8% greater than those who did. The likelihood ratio of algorithm A (positive for ILD by physical examination or CXR) was 3.9, compared with 3.2 for algorithm B (which included patients with FVC less than 70%) and 2.2 for algorithm C (which included patients with FVC less than 80%). The prevalence of ILD in a large, unselected SSc cohort was estimated to be 52.3%.
The authors noted that their proposed rule will help clinical decision making by informing clinicians on the probability of disease occurring in a given patient.