Interstitial Lung Disease (ILD) defines any disease that affects the interstitium and the distal alveoli of the lungs, leading to impaired lung diffusion. It is a heterogeneous group of different diseases of unknown and known cause with common functional characteristics (restrictive physiology and impaired gas exchange) and a common final pathway, eventually leading to irreversible fibrosis [1,2,3].

Although well over 100 distinct entities of ILDs are recognized, a limited number of disorders, including idiopathic pulmonary fibrosis, sarcoidosis and connective tissue disease-related ILDs, account for most ILDs encountered clinically [4].

Some factors have been identified to be associated with poorer prognosis and shorter survival time among ILDs patients are older age, smoking status (smokers and ex-smokers), lower body mass index, more impaired pulmonary function (mainly on forced vital capacity, FVC, total lung capacity, TLC and diffusing capacity for carbon monoxide, D_LCO), radiological findings (usual interstitial pneumonia, UIP), a pattern or greater extent of fibrosis and the development of acute exacerbations or comorbidities, especially pulmonary hypertension and emphysema [5].

Little is known on the characteristics of patients diagnosed with idiopathic pulmonary fibrosis (IPF) in this hilly area of northern India. The present study was done to evaluate the Socio-demographic and etiological profile of Interstitial Lung Diseases (ILDs) patients.

Aims and Objectives

To study the Socio-demographic and etiological profile of Interstitial Lung Diseases (ILDs) patients.

The present study was conducted at Indira Gandhi Medical College, Shimla which is a tertiary care center of Himachal Pradesh, located in North India in Asian Continent and covers the majority of the population of this state. All consecutive patients of Interstitial Lung Diseases (ILDs), attending the outpatient services of the Department of Pulmonary Medicine, IGMC Shimla from July 2018 to June 2019 were screened for enrolment in the study. All types of ILDs were enrolled in the study.

Inclusion Criteria

Stable ILD Patients: Diagnosis of ILD according to ATS/ERS guidelines based on an overall assessment of High-Resolution Computed Tomography (HRCT) scan, lung function tests, (bronchoscopy and biopsy, if available) Age >18 years, written consent.

Exclusion Criteria:

• Subjects with evidence of left heart disease, Chronic kidney disease, Liver disease

• Chronic lung diseases other than ILDs

• Patients with HIV

• Pregnant

Patients presenting with respiratory symptoms such as cough, shortness of breath and diagnosed cases of ILD were evaluated. 

All consecutive ILD patients were subjected to focused history and physical examination as structured questionnaire record information related to; Demographics, Duration of ILD symptoms etc.

The data was collected, entered in the MS Excel sheet and analyzed using Epi info V7 software. Continuous variables were reported as mean ± SD or median and interquartile range depending on the distribution of the variables. Categorical variables were recorded as counts and percentages. Differences between means of continuous variables were compared using the unpaired student’s’ test. A p-value of <0.05 was considered as statistically significant.

Among the study population, 50 patients 27 (54%) were female and 23 (46%) were male. The mean age of the study population was 57.821+5.03years. The mean age of males and females was 62.561+3.84 years and 53.771+5.07 years respectively. 44(88%) were of rural background and majority were from the lower class of socioeconomic status. The prevalence of active smoking was reported in small percentage of the patients 2(4%). The majority of the study population was either ex-smokers 17(34%) or non-smoker 31(62%). The mean duration of symptoms of ILD was 3.034+2.62 years. There was no significant difference between males and females regarding the duration of illness (2.76+2.46 years versus 3.39+2.77 years, p = 0.40). Among the study population, a total of 8 (16%) had a history of ATT intake among these 5 (18.52%) were female 3(13.04%) were male. A total of 10 (20%) patients were on domiciliary oxygen therapy, among these 6 (26.09%) were male.

Table 1: Socio-Demographic and Etiological Profile of the Study Population (n = 50)

Figure 1: Socio-Demographic and Etiological Profile of the Study Population (n = 50)

All (n = 50) patients of Interstitial Lung Diseases (ILD) were screened for PAH by echocardiography, among these 24 (48%) had  Idiopathic Pulmonary Fibrosis (IPF), 11(22%) had sarcoidosis, 8(16%) had systemic sclerosis-associated Interstitial Lung Diseases (PSSc-ILD), 3(6%) had Systemic Lupus Erythematous associated Interstitial Lung Diseases (SLE-ILD), 1(2%) patient had Combined Pulmonary Fibrosis and Emphysema (CPFE ) and 3(12%) patients had suffered from Hypersensitive Pneumonitis (HP) (Table 1 ).

The mean age of the study population was 57.821+5.03 with male and female mean age 62.561+3.84 and 53.77+15.07 respectively (Figure 1). Females were more than male and younger with a mean duration of ILD of 3.034±2.62 years. A similar finding was also reported in the study conducted by Agarwal et al. [6] In the ILD registry of Indian data, it was reported that ILDs occur at a younger age compared to the western countries and females are affected more [7].

Most of ILD patients were females, were of rural background, from the lower class of socioeconomic status and either ex-smokers or non-smoker. IPF, Sarcoidosis and CTD-ILDs were the most common ILDs seen at a tertiary center of hilly state in northern India.

Limitations of the Study

The small number of the population were included in this study represents a methodological limitation and study over a larger population is recommended.

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