Factors associated with quality of life among patients with chronic plaque psoriasis: A cross-sectional multicentre study in Sri Lanka

Introduction: Chronic plaque psoriasis (CPP) has a considerable negative impact on patients’ health-related quality of life (QoL). This study investigated the sociodemographic and disease characteristics associated with QoL of patients with CPP.
Methods: This Cross-sectional multicentre study included 297 patients with CPP, aged 18 years or older attending dermatology clinics of National Hospital Galle, General Hospitals Matara and Hambantota. The QoL was assessed using Sinhala validated versions of Dermatology Life Quality Index (DLQI) and Psoriasis Disability Index (PDI) while disease severity was determined by psoriasis area severity index (PASI) and the involvement of body surface area (BSA). 
Results: The study participants had a median age of 55 years (IQR: 42-63), with 57.6% being males. Median (IQR) PASI and BSA were 4.8 (2.8-10.2) and 9% (4.5-21), respectively. Based on DLQI estimation, 35% subjects had moderate to severe impairment of QoL while further 40% had mild impairment. Median (IQR) PDI score was 6 (3-10).
Both BSA and PASI showed significant and positive correlations with DLQI and PDI (spearman rho for BSA/DLQI 0.24, PASI/DLQI 0.18, BSA/PDI 0.32, PASI/PDI 0.31, p<0.01 for all). Age showed negative correlations with both DLQI and PDI (spearman rho for DLQI -0.26, PDI -0.25, p<0.01 for both). The impairment of QoL and disability was greater among men compared to women, current smokers compared to past or non-smokers, and those with lower limb involvement or pruritus compared to those without. There was no association between duration of the disease, level of education and social class with either the QoL or disability.
Conclusions: In patients with CPP, greater skin involvement, male gender, and being young are associated with poor QoL determined by both skin and disease specific tools.