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Evaluation of lung function tests in rheumatoid arthritis patients.

ABSTRACT

Background: Pulmonary manifestation is one of the most common extra-articular features in rheumatoid arthritis (RA) leading to significant morbidity. Lung function testing helps in identifying the type of respiratory defect. Early detection helps in effective management of the lung involvement in RA. Aims and Objectives: In this study, we compared the lung function of RA patient with the normal controls. Materials and Methods: Spirometry was performed in 100 participants (50 RA patients and 50 normal controls). Lung parameters such as forced vital capacity, forced expiratory volume in 1 s, forced expiratory flow in 25-75%, and peak expiratory flow rate were measured. Statistical analysis was performed, P < 0.05 was considered statistically significant. Result: In this study, restrictive ventilatory defect was seen in 64% of patients, and obstructive ventilatory defect was seen in 10% of patients. Pulmonary function abnormalities are common in asymptomatic rheumatoid patients which were found to be restrictive defect. Conclusion: Restrictive ventilatory defect may be due to idiopathic pulmonary fibrosis characterized by high levels of rheumatoid factor, antinuclear antibody and deposits of immunoglobulin A, and complement on the alveolar wall. Screening of RA patients with spirometer helps in early detection of pulmonary involvement.

KEY WORDS: Rheumatoid Arthritis; Restrictive Defect; Spirometer

INTRODUCTION

[ILLUSTRATION OMITTED]

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease of unknown etiology. It is characterized by symmetrical peripheral polyarthritis [1] associated with systemic involvement. There is an increase in rheumatoid factor level. It affects nearly 1% of population. [2] The participants with HLAD4 and HLADR4 are prone to develop RA. The female to male ratio is 3:1. [2] The incidence increases between 25 and 55 years of age reaching a plateau till the age of 75 years and decreases. Risk factors such as genetic factors, infectious agent, oral contraceptive pills, and smoking play a role in etiology. Extra-articular manifestations are more common. Pulmonary involvement seen in 30% of cases is mostly asymptomatic. It is because these patients are physically less active due to chronic pain and fatigue so less likely to develop breathlessness. [3] Pulmonary involvement contributes to morbidity and mortality in rheumatoid patients. It is the second common cause of death. [4] Pulmonary manifestations may be pleurisy, parenchymal nodule, interstitial lung disease, airway disease, pulmonary fibrosis, bronchiolitis, and bronchiectasis. [3] Interstitial lung disease and alveolitis are seen in 40% of RA patients with high levels of rheumatoid factor titer which leads to respiratory failure. [5,6] Lung function was assessed by spirometry which is non-invasive and cost effective and helps in early diagnosis. It can be used to assess the prognosis of the respiratory involvement and provide a comfortable and healthy lifestyle.

MATERIALS AND METHODS

The study was performed in Department of Physiology and Rheumatology, Outpatient Department in SRM Medical College Hospital and Research Centre. The study was performed in 100 participants, 50 healthy controls and 50 RA patients. Information regarding respiratory symptoms, duration of disease, drug history, blood investigations such as RA factor, C-reactive protein, anti-cyclic citrullinated peptide, and hemoglobin were obtained. Anthropometric measurements, physical examination, and assessment of lung function were performed on all the study participants. Lung function test was assessed by EasyOne Pro computerized spirometer.

The study was approved by the Institutional Ethical Committee. Written informed consent was obtained from all the participants.

Inclusion Criteria

* Proven RA patients on rheumatoid drugs (ARA Criteria, 2010)

* Absence of respiratory symptoms

* Age group--25-60 years.

Exclusion Criteria

* Age <25 years, >60 years

* Smokers, alcoholics

* Pregnancy

* Any previous respiratory and cardiac disease

* Previous significant chest injury.

Procedure

The participant was made to relax and should wear comfortable loose clothing. The participant was made to sit comfortably and nose clip was applied on the nose. The spirette was kept in the mouth with the lips sealing around it. The participants were instructed to breathe calmly and care should be taken not to block or bite the spirette.

The participants were asked to do tidal breathing and fill the lungs completely and then asked to exhale as hard and fast as possible until the lungs were completely empty and inhale as hard and fast as possible till the end of the test. This test was repeated 2-3 times and the best value was taken for the result.

Statistical Analysis

The data collected were analyzed using Statistical Package for the Social Sciences version 21. Statistical analysis was performed using independent t-test to compare the lung function tests between the healthy controls (control group) and RA patients (experimental group). The P < 0.05 was considered as statistically significant.

RESULTS

The study was performed in 100 participants (50 control group and 50 experimental group). 85% were female participants and 15% were male participants. Table 1 describes about the anthropometric values of our study population. The mean age of the experimental group is 41.96 [+ or -] 7.99 years. The mean height and weight are 156.7 cm and 61.46 kg, respectively. The mean body mass index is 24.5[+ or -] 6.0.

Table 2 shows the comparison of lung parameters between the control and experimental group. The mean of experimental group of forced vital capacity (FVC) was 2.2366 [+ or -] 0.59186, forced expiratory volume in 1 s (FEV1) was 1.7594 [+ or -] 0.51072, FEV1/FVC was 0.79 [+ or -] 0.13, forced expiratory flow in 25-75% (FEF 25-75%) was 1.756 [+ or -] 0.93667, peak expiratory flow rate (PEF) was 4.1528 [+ or -] 1.45828, FIVC was 1.7936 [+ or -] 0.95744, and PIF was 2.1346 [+ or -] 1.35958 were significantly lower when compared with the control group.

Figure 1 shows the pie chart about the ventilatory defect. About 64% of rheumatoid patients had restrictive ventilatory defect and 10% of rheumatoid patients had obstructive type. About 26% had normal lung function.

DISCUSSION

In this study, the pulmonary functions were performed in 50 rheumatoid patients and compared them with normal controls.

Restrictive ventilatory defect is seen in 64% of rheumatoid patients with FEV1/FVC >70% and reduced vital capacity and total lung capacity.

Obstructive ventilatory defect is seen in 10% of rheumatoid patients since the FEV1/FVC <80% with increased residual volume and total lung capacity ratio.
Normal       26%
Restrictive  64%
Obstructive  10%

Figure 1: Ventilatory defects in experimental group

Note: Table made from bar graph.


Remaining 26% of participants were normal. Lung parameters such as FVC, FEV1, FEV1/FVC, FEF 25-75%, PEF, and FIVC were significantly lower in rheumatoid patients when compared with normal controls.

Fuld et al. [7] found that the prevalence of pulmonary function abnormalities was higher in asymptomatic rheumatoid patients when compared with the reference population. Avnon et al. [8] noted restrictive pulmonary abnormalities in 25.6%, small airway disease in 14.6%, and obstructive in 27%. Cortet et al. [9] and Radoux et al. [10] found small airway obstruction is seen in 50% of cases with decrease in FEF 25-75%. There was associated increase in antinuclear antibody. [10]

Restrictive ventilatory defect may be due to activation of immune complexes in the alveolar walls. It results in the release of myeloperoxidase, collagenase, and elastase. There is destruction of lung tissue by phagocytosis and protease--Antiprotease imbalance preventing the lung expansion. Banks et al. [11] stated restrictive type of lung disease with reduction in mid-expiratory flow. Restrictive pattern was seen with reduction in FEV1/FVC ratio. [8] Gowdhaman et al. [12] reported restrictive type with decrease in vital capacity.

Bilgici et al. [13] and Vergnenegre et al. [14] noted obstructive type of lung disease. Vergnenegre et al. [14] reported a significant reduction in FEF 25-75%, FEV1/FVC. In RA, obstructive ventilatory defect may be due to airway inflammation. Plasma immunoglobulin E level increases. Neuropeptides and chemokines are released from eosinophils, and mast cell damages the airway epithelium and hyperresponsiveness. This results in partially reversible airway obstruction due to bronchial narrowing. Devouassoux et al. [15] found that there is airflow obstruction with decreased FEV1/FVC and hyperinflation with increased residual volume and total lung capacity ratio. Cimen et al. [16] found airway obstruction in 28% of cases. Hassan et al. [17] reported that airway obstruction may be due to mucosal edema as a result of airway inflammation which leads to bronchial narrowing.

The current study states that pulmonary manifestations are common in RA which is of restrictive type.

CONCLUSION

Pulmonary manifestations are one of the common extra-articular manifestation in RA. It is often asymptomatic. They can be evaluated with pulmonary function tests, chest radiography, and CT scan. In this study, restrictive ventilatory defect is more common than obstructive type. Pulmonary function test can be used as screening test for early detection of the abnormalities and disease activity.

ACKNOWLEDGMENT

We sincerely thank our participants who enthusiastically accepted to participate and devote their valuable time to the study. We thank Dr. Panchapakesan, Dr. S. Kanimozhi, and Department of Physiology, for rendering the support for the study.

REFERENCES

[1.] Arnett FC, Edworthy SM, Bloch DA, McShane DJ, Fries JF, Cooper NS, et al. The American Rheumatism Association 1987 Revised Criteria for the classification of rheumatoid arthritis. Arthritis Rheum. 1988;31(1):315-24.

[2.] Gabriel SE. The epidemiology of rheumatoid arthritis. Rheum Dis Clin North Am. 2001;27(2):269-81.

[3.] Pappas DA, Giles JT, Connors G, Lechtzin N, Bathon JM, Danoff SK. Respiratory symptoms and disease characteristics as predictors of pulmonary function abnormalities in patients with rheumatoid arthritis: An observational cohort study. Arthritis research & therapy. 2010;12(3):R104.

[4.] Anaya JM, Diethelm L, Ortiz LA, Gutierrez M, Citera G, Welsh RA, et al. Pulmonary involvement in rheumatoid arthritis. Semin Arthritis Rheum. 1995;24(4):242-54.

[5.] Tanoue LT. Pulmonary manifestations of rheumatoid arthritis. Clin Chest Med. 1998;19(4):667-85, viii.

[6.] DuBois RM, Au W. Infiltrative and ILD. In: Murray JF, Nadel JA, editors. Textbook of Respiratory Medicine. Philadelphia, PA: W. B. Saunders Co.; 2000.

[7.] Fuld JP, Johnson MK, Cotton MM, Carter R, Watkin SW, Capell HA, et al. A longitudinal study of lung function in nonsmoking patients with rheumatoid arthritis. Chest. 2003;124(4):1224-31.

[8.] Avnon LS, Manzur F, Bolotin A, Heimer D, Flusser D, Buskila D, et al. Pulmonary functions testing in patients with rheumatoid arthritis. Isr Med Assoc J. 2009;11(2):83-7.

[9.] Cortet B, Perez T, Roux N, Flipo RM, Duquesnoy B, Delcambre B, et al. Pulmonary function tests and high resolution computed tomography of the lungs in patients with rheumatoid arthritis. Ann Rheum Dis. 1997;56(10):596-600.

[10.] Radoux V, Menard HA, Begin R, Decary F, Koopman WJ. Airways disease in rheumatoid arthritis patients. One element of a general exocrine dysfunction. Arthritis Rheum. 1987;30(3):249-56.

[11.] Banks J, Banks C, Cheong B, Umachandran V, Smith AP, Jessop JD, et al. An epidemiological and clinical investigation of pulmonary function and respiratory symptoms in patients with rheumatoid arthritis. Q J Med. 1992;85(307-308):795-806.

[12.] Gowdhaman N, Adikesavan B, Gopal MK, Meganathan M, Mohan J, Balamurugan K et al. A comparative study on pulmonary function in females with rheumatoid arthritis. World J Med Sci. 2011;6(4):209-13.

[13.] Bilgici A, Ulusoy H, Kuru O, Celenk C, Unsal M, Danaci M. Pulmonary involvement in rheumatoid arthritis. Rheumatol Int. 2005;25(6):429-35.

[14.] Vergnenegre A, Pugnere N, Antonini MT, Arnaud M, Melloni B, Treves R, et al. Airway obstruction and rheumatoid arthritis. Eur Respir J. 1997;10(5):1072-8.

[15.] Devouassoux G, Cottin V, Liote H, Marchand E, Frachon I, Schuller A, et al. Characterisation of severe obliterative bronchiolitis in rheumatoid arthritis. Eur Respir J. 2009;33(5):1053-61.

[16.] Cimen B, Deviren SD, Yorgancloglu ZR. Pulmonary function tests, aerobic capacity, respiratory muscle strength and endurance of patients with rheumatoid arthritis. Clin Rheumatol. 2001;20(3):168-73.

[17.] Hassan WU, Keaney NP, Holland CD, Kelly CA. Bronchial reactivity and airflow obstruction in rheumatoid arthritis. Ann Rheum Dis. 1994;53(8):511-4.

Kalyani Praba P (1), Thamarai Selvi K (1), Vijay Anand B (2), Saravanan A (1)

(1) Department of Physiology, SRM Medical College, Hospital & Research Institute, Kattankulathur, Chennai, Tamil Nadu, India, (2)Department of Orthopedics, SRM Medical College, Hospital & Research Institute, Kattankulathur, Chennai, Tamil Nadu, India

Correspondence to: Kalyani Praba Premsundar, E-mail: kalyanipraba@gmail.com

Received: February 18, 2017; Accepted: March 03, 2017

How to cite this article: Kalyani Praba P, Thamarai Selvi K, Vijay Anand B, Saravanan A. Evaluation of lung function tests in rheumatoid arthritis patients. Natl J Physiol Pharm Pharmacol 2017;7(7):693-696.

Source of Support: Nil, Conflict of Interest: None declared.
Table 1: The anthropometric measurements

Parameters  Groups        N   Mean[+ or -]Standard deviation

Height      Control       50     163.4400[+ or -]6.87545
            Experimental  50     156.7000[+ or -]7.98787
Weight      Control       50      64.9200[+ or -]10.08300
            Experimental  50      61.4600[+ or -]12.41002
BMI         Control       50      24.1900[+ or -]3.63016
            Experimental  50      24.5116[+ or -]6.00274
Age         Control       50      39.1800[+ or -]5.79123
            Experimental  50      41.9600[+ or -]7.99990

Parameters  Independent t-test  P value

Height            4.522         0.0001

Weight            1.530         0.129

BMI               0.324         0.747

Age               1.990         0.049

BMI: Body mass index

Table 2: The comparison of lung parameters

Parameters  Groups        N   Mean[+ or -]Standard deviation

FVC         Control       50      3.2302[+ or -]0.61001
            Experimental  50      2.2366[+ or -]0.59186
FEV1        Control       50      2.7142[+ or -]0.51323
            Experimental  50      1.7594[+ or -]0.51072
FEV1/FVC    Control       50      0.8425[+ or -]0.07708
            Experimental  50      0.7900[+ or -]0.13036
FEF 25-75%  Control       50      2.9526[+ or -]0.74651
            Experimental  50      1.7560[+ or -]0.93667
PEF         Control       50      6.5024[+ or -]1.78818
            Experimental  50      4.1528[+ or -]1.45828
FET         Control       50      5.5380[+ or -]1.74799
            Experimental  50      6.0146[+ or -]3.40398
FIVC        Control       50      3.0764[+ or -]0.83833
            Experimental  50      1.7936[+ or -]0.95744
PIF         Control       50      3.7842[+ or -]1.43782
            Experimental  50      2.1346[+ or -]1.35958

Parameters  Independent t-test  P value
FVC               8.266         0.0001

FEV1              9.325         0.0001

FEV1/FVC          2.454         0.016

FEF 25-75%        7.064         0.0001

PEF               7.200         0.0001

FET               0.881         0.381

FIVC              7.128         0.0001

PIF               5.895         0.0001

FVC: Forced vital capacity, FEV1: Forced expiratory volume in 1 s, PEF:
Peak expiratory flow rate, FET: Forced expiratory time, FEF 25-75%:
Forced expiratory flow in 25-75%, FIVC: Forced inspiratory vital
capacity, PIF: Peak inspiratory flow
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Title Annotation:RESEARCH ARTICLE
Author:Praba P., Kalyani; Selvi K., Thamarai; Anand B., Vijay; A., Saravanan
Publication:National Journal of Physiology, Pharmacy and Pharmacology
Article Type:Report
Date:Jul 1, 2017
Words:2391
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