Background :

Psoriasis is associated with altered pulmonary function. Methotrexate may affect lung function status in psoriatic patients, while the effect of other antipsoriatic medications on lung function was not evaluated in this study.

Objectives :

To assess pulmonary function test (PFT) parameters among psoriatic patients receiving methotrexate in relation to duration of treatment.

Methods :

This cross-sectional study was carried out in the Department of Physiology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Shahbag, Dhaka, from July 2012 to June 2013. A total of 120 subjects were selected, including 30 apparently healthy controls (Group A) and 90 diagnosed male psoriatic patients (study Group B). Controls were selected from the community, and patients were recruited from the inpatient and outpatient departments of Dermatology and Venereology, BSMMU.

Based on treatment, study subjects were further divided into three groups, each consisting of 30 male subjects.

Results :

The mean age (?SE) was 33.5?1.424, 34.5?1.401, 35.27?1.44, and 34.8?1.212 years in groups A, B1, B2, and B3 respectively, with no statistically significant differences among groups. The groups were matched for age.

The mean BMI (?SE) was 23.557?0.584, 23.089?0.721, 23.986?0.579, and 23.155?0.595 in groups A, B1, B2, and B3 respectively, with no statistically significant differences among groups.

All control subjects (Group A) had normal lung function tests (LFT). In contrast, 19 (63.33%) in B1, 20 (66.67%) in B2, and 29 (96.67%) in B3 had abnormal lung function tests.

In Group B1, restrictive disorder was found in 9 (30%) patients. In Group B2, restrictive disorder was found in 10 (33.33%) patients. In Group B3, restrictive disorder was found in 23 (76.67%) patients. No small or large airway obstruction was observed in most subgroups.

Among 90 psoriatic patients, 42 (46.67%) were diagnosed with restrictive disorder; 12 had pulmonary symptoms while 30 were asymptomatic.

Correlation analysis showed mixed relationships between lung function parameters and duration of therapy. Some parameters (FVC, FEV1) showed statistically significant associations in groups B1 and B3, while most other relationships were not statistically significant.

Conclusion :

This cross-sectional study indicates that psoriatic patients receiving methotrexate have a higher frequency of abnormal lung function tests compared to controls. Most pulmonary function parameters showed non-significant correlations with treatment duration, although FVC and FEV1 demonstrated statistically significant associations in certain groups.