Development and validation of screening tool to screen Interstitial lung diseases (DeSTILD)

1. Introduction

Interstitial lung disease (ILD) comprises over 100 pulmonary disorders characterized by alveolar inflammation leading to progressive fibrosis. A recent Global Burden of Disease study revealed a 51% increase in global ILD incidence over the past decade. Worldwide, crude annual ILD incidence and prevalence range from 1 to 70.1 and 6.27 to 97.9 per 100,000 populations, respectively. In the UK, ILD incidence is estimated at 26-32 per 105 people annually. In India, a 2022 study reported a crude annual incidence of 10.1–20.2 and prevalence of 49.0–98.1 per 100,000 populations, highlighting a significant burden. However, underdiagnosis and underreporting prevail due to a scarcity of high-quality HRCT scanning equipment and limited awareness. Patients often endure prolonged waits and multiple evaluations before receiving a correct ILD diagnosis. Despite these observations, diagnostic delays remain common. Since a majority of the patients present with symptoms present at the primary care level, screening at this level is becomes extremely important to avoid further delays. Thus, there is a need to develop a screening tool that can distinguish ILD from other respiratory diseases at an early stage of the disease at the primary level. Therefore, in this project, we will develop and validate a tool for screening ILD that can successfully distinguish ILD from other respiratory disorders so that patients with ILD can be diagnosed at an early stage of the disease and receive early treatment to reduce suffering and complications caused by late or misdiagnosis of ILD.

1.     Objective: - To develop and validate a tool to screen Interstitial lung diseases

2.     Methodology: The study will be conducted in two phases   -

Phase 1: Development of the screening tool for ILD

Phase 2: Validation of the tool

Phase 1: Phase 1 of the study will be the development of screening tools for ILD.

i.          Literature review: -  The following databases will be used to select published peer-reviewed articles -> PubMed, Medline, Cochrane, JSTOR, EBSCO, and Google Scholar. ILD, IPF, HP, CTD-ILD, Sarcoidosis, Ocuupational-Environmental, Drug-induced ILD, Screening,Tools,Validity, and Reliability, these phrases will be used both individually and collectively. Reviewing all relevant research materials. In the investigation, unnecessary and redundant information will be eliminated.

ii.          Face validation: Following the extraction of the initial pool of questionnaire items from the literature review, there will be a face validity exercise in which qualified respiratory experts will evaluate the items. This step will include 5-6 experts and will essentially be a qualitative step. The experts will review the items in the checklist/questionnaire for logical sequence, standardized terms, and how much each item contributes towards identifying/screening individuals and that they meet the screening tool’s objectives.

iii.          Content validation: Following face validation, the questionnaire will be modified based on the recommendations of subject matter experts, and then subject matter experts (n=15) will conduct content validation. On a scale of 1 to 4, they will evaluate the questions’ relevance, with 1 signifying no relevance and 4 indicating high relevance.

After content validation analysis, the tool will be administered in the patients for validation, reliability, sensitivity, and specificity.

 Phase 2:  Validation of the tool

In the second phase of the study psychometric validation of the tool will be carried out**.**

·       Inclusion Criteria

a)     Patients of either gender who are 18 years and above and willing to provide consent to voluntarily participate in this registry.

b)     Patients coming to the physician for respiratory ailments and breathlessness

 Â·       Exclusion Criteria

a)   Individuals suffering from malignancies and any serious co-morbidity and existing end-organ damage, dementia, and psychotic illness.

**Study duration-**Study will be conducted in two stages

·       Development of the screening tool for ILD: 4 Months

·       Validation of the tool: 9 Months

5. Sample Size and data collection: 2 steps will be involved in the development of the screening tool

i.          Face validation by respiratory experts (n)= 5-6. Respiratory experts will face validate the questionnaire using Google docs

ii.          Content validation by subject experts (n)=15. Fifteen respiratory experts will be involved in the process of content validation and this will be done using Epi collect 5 plat form.

Validation of the tool: Multicentric study will be collected for psychometric validation of tool. No of sample size will be= No. of items * 15 cases. Online Semi structured questionnaire will be prepared using Epi collect 5 platforms.

Designing Database: Data collected on the Online platform will be exported in the form of a CSV file then the respective file will be imported to SPSS for analysis for further analysis.

Statistical Methods

Content validation: Content validity analysis will be conducted and Content validity of every individual Question (Item) (I-CVI) will be calculated.

Items that score less than 70% will not be considered in calculating the content validity of the whole questionnaire i.e. S-CVI/Ave.

Content validity of the whole questionnaire(S-CVI/Ave) will be calculated using three different method.

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