From the Guidelines
The Psoriasis Area and Severity Index (PASI) and Dermatology Life Quality Index (DLQI) typically show a moderate positive correlation, meaning that as PASI scores increase, DLQI scores also tend to increase, indicating a greater impact on quality of life. This correlation is supported by the British Association of Dermatologists' guidelines for biologic therapy for psoriasis 2017 1, which suggests that patients with psoriasis requiring systemic therapy should be considered for biologic therapy if they have a large impact on physical, psychological, or social functioning, as measured by the DLQI, and meet certain disease severity criteria, including a PASI score of 10 or higher.
Key Points to Consider
- The relationship between PASI and DLQI is important because it demonstrates that the physical severity of psoriasis often affects patients' quality of life, though individual responses vary significantly 1.
- Some patients with relatively mild psoriasis according to PASI may experience substantial quality of life impairment if lesions are in visible or sensitive areas, while others with more extensive disease may report less impact on their daily functioning 1.
- The DLQI is a validated tool for measuring quality of life across all skin diseases, including psoriasis, and a score of > 10 has been shown to correlate with at least a very large effect on an individual's quality of life 1.
- Clinicians should consider both PASI and DLQI measures when making treatment decisions, as improvement in both physical symptoms and quality of life represents optimal therapeutic success.
Clinical Implications
- Assessing both objective disease severity (PASI) and subjective patient experience (DLQI) is crucial when evaluating psoriasis and determining treatment approaches.
- The decision to proceed with biologic therapy should be made in collaboration with the patient, taking into account the associated risks and benefits, and considering the impact of psoriasis on the patient's quality of life, as measured by the DLQI 1.
From the Research
Correlation Between PASI and DLQI
- The correlation between the Psoriasis Area and Severity Index (PASI) and the Dermatology Life Quality Index (DLQI) has been studied in various research papers 2, 3, 4, 5, 6.
- A systematic review and meta-analysis found that PASI 90 responders had a 12% greater improvement in DLQI score compared to PASI 75-89 responders 2.
- Another study found a significant association between the PASI and DLQI scores in patients with moderate-to-severe psoriasis, with a correlation coefficient of 0.37 (P < 0.001) 5.
- A pooled analysis of four phase 3 clinical trials found that improvements in PASI scores were directly related to improvements in DLQI domain scores, with moderate to strong correlations over the sustained exposure period (β range, 0.63-0.69; all P < 0.001) 4.
- A longitudinal study found that PASI and DLQI scores were highly correlated over all time points (ρ = 0.50), and that DLQI scores significantly decreased by 0.8 units per year from 12 months to 6.5 years (P = 0.002) 6.
Factors Affecting the Correlation
- Psoriatic foot involvement was found to be the most significant contributor to the inconsistency between PASI and DLQI scores, with an odds ratio of 2.109 (95% CI: 1.581-2.815) 5.
- Other factors that affected the correlation between PASI and DLQI scores included female sex, age, psoriatic arthritis, higher income, and family history of psoriasis 5.
- Exposed lesions, such as those on the scalp, face, neck, nails, and hands, were also positively associated with severely impaired quality of life 5.
Clinical Implications
- The correlation between PASI and DLQI scores suggests that improvements in clinical efficacy are associated with improved quality of life in patients with moderate-to-severe psoriasis 2, 4.
- The findings of these studies highlight the importance of considering both clinical and quality of life outcomes when treating patients with psoriasis 2, 4, 6.