An observational study in Interstitial Lung Disease (ILD), Idiopathic Pulmonary Fibrosis (IPF) and Progressive Pulmonary Fibrosis, sponsored by Hospital de Granollers. Recruiting at 1 site in Spain. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-07-23.
Sponsored by Hospital de Granollers · Observational
The OXISITE-ILD study is a prospective, multicenter, observational study designed to evaluate the agreement between finger (digital) and earlobe (auricular) pulse oximetry for measuring oxygen saturation (SpO2) during the six-minute walk test (6MWT) in patients with interstitial lung disease (ILD). In routine clinical practice, exercise SpO2 is usually measured at the finger; however, the finger reading can be unreliable in some patients, and there is currently no recommendation on the best sensor location in ILD. This study compares the two sensor locations, recorded at the same time, and evaluates whether any disagreement changes how exercise desaturation is classified and whether ambulatory oxygen is indicated.
All patients undergoing a 6MWT as part of routine ILD care are included consecutively to ensure a pragmatic, real-world representation of the ILD population. The primary objective is to measure the agreement between the two locations in the lowest SpO2 reached during the test, including the size and direction of any difference. Secondary objectives include the reclassification of patients at the clinical desaturation thresholds, the comparison between autoimmune and non-autoimmune ILD, the rate of invalid readings at each location, and the clinical, vascular and functional factors associated with disagreement.
OXISITE-ILD is a prospective, consecutive, multicenter, observational, cross-sectional method-comparison (agreement) study.
Each participant is assessed once, during a single 6MWT performed as part of routine care. SpO2 and heart rate are recorded simultaneously at the finger and at the earlobe with two pulse oximeters, at eight timepoints: baseline, each of minutes 1 to 6, and after a 2-minute recovery. The paired heart rate at each timepoint is used as a signal-quality control, so that agreement is assessed only on simultaneous, valid readings. In some participants, an arterial blood gas or a nailfold capillaroscopy may also be performed to help interpret the difference between locations.
A minimum of 100 participants is planned at the coordinating center, sufficient on its own for the primary objective; recruitment may be extended at the coordinating center and at the collaborating centers as the study requires. The participation of collaborating centers is opportunistic and adds precision, subgroup analyses, and external validity.
576 studies on the registry are indexed under Idiopathic Pulmonary Fibrosis; 123 are open to participants now.
This study's planned enrollment of 100 is below the median of 152 across 165 observational studies indexed under Idiopathic Pulmonary Fibrosis.
Browse Idiopathic Pulmonary Fibrosis studies →Hospital de Granollers is the lead sponsor of 27 studies on the registry; 5 are open to participants now.
Compared within Idiopathic Pulmonary Fibrosis, this study's primary condition as ClinicalTrials.gg classifies it; the registry's first condition term is Lung Diseases, Interstitial. The counts are of registry records indexed under each term, refreshed daily. How we classify →
Consecutive adults with a confirmed diagnosis of interstitial lung disease (ILD), either newly diagnosed or under follow-up, attending the ILD/pulmonary fibrosis units of the participating centres and undergoing a clinically indicated 6-minute walk test. Patients with or without prior oxygen therapy are enrolled consecutively, and baseline oxygen status (none, exertional only, or at rest) is recorded. Each patient is assessed on a single occasion, consistent with the cross-sectional design.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Adults with an established diagnosis of interstitial lung disease (ILD) undergoing a six-minute walk test (6MWT) as part of routine care. Each participant is assessed once, with oxygen saturation (SpO2) and heart rate recorded simultaneously at the finger and at the earlobe. Pre-specified subgroups for the analysis are autoimmune-associated versus non-autoimmune ILD.
Other: Dual-site pulse oximetry (finger and earlobe)
During a single 6MWT, SpO2 and heart rate are recorded simultaneously at the finger (digital) and the earlobe (auricular) with two pulse oximeters, at eight timepoints (baseline, minutes 1 to 6, and a 2-minute recovery). No treatment is administered and routine clinical management is not modified; the procedure adds the simultaneous earlobe measurement for comparison with the finger.
Intraclass correlation coefficient for agreement in minimum SpO2 between sensor locations
Absolute agreement in minimum SpO2 during the six-minute walk test between the finger and earlobe sensors, quantified with the intraclass correlation coefficient (two-way mixed-effects model, absolute agreement) and its 95% confidence interval. ICC values are interpreted as below 0.50 poor, 0.50 to 0.75 moderate, 0.75 to 0.90 good, and above 0.90 excellent agreement.
Time frame: Day 1
Bland-Altman agreement in minimum SpO2 between sensor locations
Agreement in minimum SpO2 during the six-minute walk test between the finger and earlobe sensors, assessed with Bland-Altman analysis: mean bias (earlobe minus finger) with its 95% confidence interval and 95% limits of agreement, evaluated against a prespecified clinically acceptable difference of 3 percentage points. The direction of the bias is reported, as the finger is hypothesised to register lower values than the earlobe.
Time frame: Day 1
Reclassification of exertional desaturation between sensor locations at SpO2 below 88%
Proportion of participants whose classification of significant exertional desaturation changes between the finger and earlobe sensors at the threshold of minimum SpO2 below 88% (American Thoracic Society indication threshold for ambulatory oxygen). Agreement is assessed with the Cohen kappa coefficient (Landis-Koch interpretation) and the difference in proportions with the McNemar test for paired data. At this threshold the McNemar test and the raw reclassification proportions are the primary read, as kappa can be unstable when prevalence is extreme.
Time frame: Day 1
Reclassification of exertional desaturation between sensor locations at SpO2 below 90%
Proportion of participants whose classification of significant exertional desaturation changes between the finger and earlobe sensors at the threshold of minimum SpO2 below 90% (British Thoracic Society indication threshold for ambulatory oxygen). Agreement is assessed with the Cohen kappa coefficient (Landis-Koch interpretation) and the difference in proportions with the McNemar test for paired data.
Time frame: Day 1
Reclassification of exertional desaturation between sensor locations at a fall in SpO2 of 4% or more
Proportion of participants whose classification changes between the finger and earlobe sensors at the prognostic threshold of a fall in minimum SpO2 of 4% or more from baseline. Agreement is assessed with the Cohen kappa coefficient (Landis-Koch interpretation) and the difference in proportions with the McNemar test for paired data.
Time frame: Day 1
Agreement in minimum SpO2 by autoimmune versus non-autoimmune ILD
Comparison of the agreement between sensor locations (intraclass correlation coefficient and Bland-Altman) in autoimmune-associated ILD versus non-autoimmune ILD, with interstitial pneumonia with autoimmune features (IPAF) described separately. Where sample size permits, agreement is also described, exploratorily and without formal hypothesis testing, by major ILD subtype (for example idiopathic pulmonary fibrosis, hypersensitivity pneumonitis, or connective tissue disease-associated ILD), and by autoimmune subtype (for example systemic sclerosis or rheumatoid arthritis).
Time frame: Day 1
Rate of invalid or poor-quality readings by sensor location
Comparison, among enrolled participants, of the rate of invalid or poor-quality (low-signal) readings between the finger and earlobe sensors during the six-minute walk test, across the eight measurement timepoints. At each timepoint the paired heart rate from the two sensors is used as a signal-quality control: a discordant heart rate flags poor signal or sensor disconnection and identifies invalid SpO2 readings, so that agreement is assessed only on simultaneous, valid readings. The per-participant difference in the rate of invalid readings between sensor locations is reported with its 95% confidence interval and the McNemar test for paired data.
Time frame: Day 1
Clinical, vascular and functional predictors of discordance
Clinical, vascular and functional factors associated with discordance between sensor locations, including ILD type (autoimmune-associated versus other), autoimmune subtype (systemic sclerosis versus other), fibrosing versus non-fibrosing ILD, pathological capillaroscopy, Raynaud phenomenon, skin pigmentation, cardiovascular comorbidity, and pulmonary function (FVC and DLCO). For each discordance criterion (SpO2 below 88%, SpO2 below 90%, and a fall of 4% or more) a logistic regression model is fitted with the patient as the unit of analysis, complemented by mixed-effects logistic regression (GLMM) with the measurement timepoint as a predictor and a random intercept per participant. Missing data from incomplete follow-up are handled by maximum likelihood; penalised regression (L1/L2) is considered if events are sparse.
Time frame: Day 1
Agreement in SpO2 at additional timepoints
Agreement between sensor locations in SpO2 at baseline, maximum, per-minute intervals during the walk, and recovery, assessed with the intraclass correlation coefficient and Bland-Altman analysis.
Time frame: Day 1
Quantitative paired difference and Passing-Bablok regression between sensor locations
Exploratory analysis of systematic differences between the finger and earlobe in SpO2. The paired difference (earlobe minus finger) is summarised with its 95% confidence interval (paired t test, or Wilcoxon signed-rank test with a Hodges-Lehmann interval, as appropriate). Passing-Bablok regression is used to detect constant and proportional differences between the two locations, with 95% confidence intervals for the intercept and the slope.
Time frame: Day 1
Agreement of each sensor location with baseline arterial oxygen saturation
Exploratory comparison of the agreement of finger and of earlobe SpO2 with baseline arterial oxygen saturation, in the subgroup of participants undergoing arterial blood gas sampling.
Time frame: Day 1
Direct and indirect cost associated with invalid finger readings
Exploratory description of the direct and indirect costs associated with invalid or poor-quality finger readings. No prespecified cost model is applied.
Time frame: Day 1
Started Jan 2026 (actual). Primary completion is estimated for Aug 2027, 18 months after the start.
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Idiopathic Pulmonary Fibrosis →
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