2520: Identification of Clinical Phenotypes in Sarcoidosis Using a Cluster Analysis

Carmen Lasa¹, Raul Fernandez-Ramon², Jorge Javier Gaitán², Jose Luis Martin-Varillas³, Rosalía Demetrio², Ivan Ferraz Amaro⁴, Santos Castañeda⁵ and Ricardo Blanco⁶, ¹Hospital Universitario Marqués de Valdecilla, IDIVAL., La Cavada, Spain, ²Hospital Universitario Marqués de Valdecilla, Santander, Spain, ³Hospital de Laredo, Laredo, Spain, ⁴Hospital Universitario de Canarias, Santa Cruz de Tenerife, Spain, ⁵Hospital de la Princesa, Madrid, Spain, ⁶Hospital Universitario Marqués de Valdecilla, IDIVAL, Santander, Spain

Background/Purpose: Sarcoidosis is a disease with heterogeneous clinical presentation and course. The objective of this study is the identification of clinical phenotypes using cluster analysis.

Methods: A model-based clustering relaying on 19 clinical variables was performed in a retrospective cohort of 342 sarcoidosis patients, diagnosed and follow-up from 1999 to 2019 in a hospital at Northern Spain. Chi-square test and ANOVA were used to compare categorical and continuous variables among groups. Two-sample t-tests and the partition of Pearson's chi-square statistic were used in pairwise comparisons. The Wasfi severity score was calculated and compared among clusters.

Results: Cluster analysis identified five groups: C1: erythema nodosum and articular involvement (n=55; 16.1%), C2: miscellaneous extrapulmonary sarcoidosis (n=49; 14.3%), C3: ocular and/or neurological involvement (n=83; 24.3%), C4: isolated hiliar adenopathy (n=17; 5.0%), and C5: parenchymal lung involvement with dyspnea (n=138; 40.4%). Lung involvement was predominant in all clusters, ranging from 89.9% (C5) to 100% (C1 and C4), except for C2 (55.1%). Extrapulmonary involvement was significantly higher in C2 (96.4%) and C3 (98.0%). Demographic and clinical characteristics are shown in Table 1. A significant low mean FEV1 was detected in C5 (90.5±21.8) versus C1 (102.0±22.9), C3 (102.3±17.6) and C4 (105.8±20.8). The cluster 5 had a significantly lower mean FVC (96.6±18.9) than the other clusters, ranging from 108.1±18.0 (C3) to 111.5±21.7 (C4). The prescription of systemic steroids and non-corticosteroid immunosuppressants was significantly higher in the clusters 1, 3 and 5. Chronicity rates were significantly higher in C3 (31.3%) and C5 (32.6%) compared to C1 (9.1%) and C4 (0%). The clusters 3 and 5 also showed significantly higher severity score values. According to the clusters identified in the present study, we proposed an individualized "treat to target" schedule by subgroups (Figure 1).

Conclusion: Five phenotypes of sarcoidosis with different clinical and prognostic characteristics are proposed in our study. Cluster analysis can be a useful tool for identifying clinical patterns in a disease as heterogeneous as sarcoidosis and facilitating its management.






C. Lasa: None; R. Fernandez-Ramon: None; J. Gaitán: None; J. Martin-Varillas: None; R. Demetrio: None; I. Ferraz Amaro: AbbVie/Abbott, 5, 6, Amgen, 5, 6, Bristol-Myers Squibb(BMS), 6; S. Castañeda: None; R. Blanco: AbbVie, 5, 6, Amgen, 6, AstraZeneca, 2, BMS, 6, Eli Lilly, 6, Galapagos, 2, 6, Janssen, 2, 6, MSD, 6, Novartis, 2, 6, Pfizer, 2, 6, Roche, 5, 6, Sanofi, 6.