Abstract Rationale The prevalence of pulmonary complications of SLE such as interstitial lung disease (ILD), pulmonary arterial hypertension (PAH), diffuse alveolar hemorrhage (DAH), shrinking lung syndrome (SLS) and acute interstitial pneumonia (AIP) are less studied. We aimed to calculate the prevalence of PAH, DAH, SLS, AIP, ILD and its radiographic pattern subclassifications among individuals with SLE. We further sought to calculate the relative risk (RR) of potentially relevant variables between SLE patients with and without ILD. Methods We searched PubMed and EMBASE for cohorts evaluating pulmonary complications in individuals with SLE. In order to be considered eligible, studies should have met the following diagnostic criteria: PAH had to be diagnosed by right heart catheterization (RHC), ILD and AIP by high-resolution or standard computed tomography, respectively, SLS according to definition by Hoffbrand et al, while DAH was diagnosed by a combination of clinical, laboratory, imaging, and pathologic findings. ILD radiographic pattern subclassifications included imaging findings compatible with ATS/ERS radiographic pattern guidelines for usual interstitial pneumonia (UIP), non-specific interstitial pneumonia (NSIP), lymphoid interstitial pneumonia, cryptogenic organizing pneumonia or other/indeterminate if not meeting any of the above criteria. Results We identified 40 eligible studies. In total, the 32 studies included in our primary outcome provided data on 30,808 patients. For our secondary outcome of ILD subclassifications, a total of patients 360 with SLE-ILD were included in 11 studies. We estimated that the pooled prevalence of ILD was 12.39% (95% CI: 9.68-15.36%) while for PAH, AIP, DAH and SLS they were 2.30% (95% CI: 1.84-2.81%), 3.05% (95% CI: 1.53-4.85%), 1.37% (95% CI: 0.70-2.22%), 1.25% (95% CI: 0.05-2.19%), respectively. Regarding ILD radiographic patterns, the prevalence of NSIP and UIP was 53.64% (95% CI: 38.98 - 68.00%) and 11.38% (95% CI: 4.78 - 19.89%), respectively among SLE patients with ILD. Finally, we detected no significant difference in the RR for hypocomplementemia or anti-Smith positivity but a 1.90 (95% CI: 1.21 - 2.98) RR for Raynaud’s phenomenon in patients with SLE-ILD compared to patients without SLE-ILD. Conclusions In this meta-analysis of more than 30,000 SLE patients, we found the prevalence of pulmonary complications in SLE more prevalent than previously recognized likely due to identification of subclinical ILD. NSIP pattern is the most common pattern in SLE-ILD while it is reassuring that DAH, SLS remain relatively rare. Targeted screening with HRCT or RHC for ILD and PAH respectively along with timely intervention in selected patients could improve outcomes. This abstract is funded by: None
Nimbvikar et al. (Fri,) studied this question.