Risk score predicts interstitial lung disease risk at first systemic sclerosis diagnosis
Click Here to Manage Email Alerts
PHILADELPHIA — A novel risk score accurately predicted interstitial lung disease in patients with systemic sclerosis at the time of diagnosis, which may reduce unnecessary CT screening, according to data presented at ACR Convergence 2022.
“The question that we wanted to investigate with our screening tool development algorithm is something that is going to help the clinician in answering the question, ‘Is now the right time to perform a high-resolution computed tomography if I want to see if my patient has signs of ILD [or] signs of pulmonary fibrosis?’” Cosimo Bruni, MD, PhD, a research collaborator at the University of Florence, in Italy, said during a press conference at the ACR meeting.
“There is a much more developed field of pulmonary arterial hypertension, where we know that we already have different screening tools available, different sets of recommendations telling when it’s time to repeat the screening, which tools should be used when screening for patients at higher risk for presenting pulmonary arterial hypertension,” he added. “Meanwhile, in the world of interstitial lung disease in systemic sclerosis, we only know that certain features of the disease may predispose [patients] to a higher risk for developing this complication.”
To develop a risk score for the presence of SSc-associated interstitial lung disease (SSc-ILD) that could guide physicians in ordering both baseline and follow-up high-resolution computed tomography (HRCT), Bruni and colleagues formed a steering committee of six experts in SSc-ILD, two research fellows and a patient partner. Members selected items for the regression analysis based on face validity, feasibility, scientific background and personal experience, using the nominal group technique.
The members of the committee developed the prediction model from baseline visits of patients with SSc to six referral centers, using multivariable logistic regression with backward selection. Patients were randomly divided into derivation (66%) and validation cohorts (33%); those with missing data regarding the selected covariates and ILD status were excluded. The researchers used a cut-off favoring a sensitivity of at least 85% from the ROC curve analysis. The derived ILD-RISC score was applied first in the validation cohort and then in a group of patients with a negative baseline HRCT.
In all, the derivation and the validation cohorts included 533 and 247 patients, respectively. Among these patients, 43% of the derivation cohort and 48% of the validation cohort exhibited interstitial lung disease.
The steering committee identified 13 variables they deemed important in predicting SSc-ILD. These included sex, age, disease duration from first non-Raynaud’s phenomenon symptom, skin subset, esophageal symptoms, ever having digital ulcers (DU), ever having arthritis, ever smoking, increased inflammatory markers, New York Heart Association (NYHA) functional class, SSc autoantibodies positivity, forced vital capacity (FVC) and diffusing capacity for carbon monoxide (DLCO).
In the derivation cohort, a model featuring FVC, DLCO, DU, age and SSc autoantibodies demonstrated an OR of 133.9 (95% CI, 53.4-335.9) and an AUC of 79.1% (95% CI, 75.3% to 83%) for the presence of SSc-ILD on HRCT. A risk score (ILD-RISC) of 0.3 or greater demonstrated a sensitivity of 85.6% and a specificity of 53.6%, figures which were replicated in the validation cohort, the researchers noted.
Among the 819 included patients with negative baseline HRCT, 20.8% developed interstitial lung disease during a 3.8-year follow-up (+/– 3 years). Longitudinally, the ILD-RISC score demonstrated comparable sensitivity and specificity. This resulted in 914 visits — nearly half of the included 1,809 — in which the HRTC could be correctly skipped after an ILD-RISC score of less than 0.3.
“Our score, at the end, is derived and validated from data, it is supported by literature and also has input from patients, so it can also reflect what is important for the patient,” Bruni said. “It can be supportive for physicians who nowadays still do not screen for interstitial lung disease at baseline, at diagnosis, in a routine way. Additionally, it can support the performance of HRCT during follow-up, and therefore can limit unnecessary tests and reduce the burden both for the patient and for the health care system.”
Collapse
Bruni C. Abstract 1526. Presented at: ACR Convergence 2022; Nov. 11-14, 2021; Philadelphia (hybrid meeting).
Click Here to Manage Email Alerts