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BACKGROUND: The Swedish National Register for Systemic Treatment of Psoriasis (PsoReg) was established in 2006. This article analyzes the implementation phase of biologics in the treatment of moderate to severe psoriasis in Sweden in the period 2006-2012. Clinical studies have shown efficacy of biologic agents in psoriasis, but their relative effectiveness in real-world clinical practice has rarely been studied.

OBJECTIVE: To estimate the incremental changes in clinical health-related quality-of-life measures in patients receiving biologics versus conventional systemic agents.

METHODS: Patients fulfilling the clinical criteria for moderate to severe psoriasis were included. Average treatment effects were estimated from longitudinal data as incremental changes in: (1) the Psoriasis Area and Severity Index (PASI) score, (2) the Dermatology Life Quality Index (DLQI) score, and (3) the EQ-5D score, by matching patients switching to biologics with patients remaining on conventional systemic agents.

RESULTS: The study included 239 biologic-treated patients and 378 conventionally treated patients. The matched patient groups were essentially equivalent in terms of important patient characteristics. The average treatment effects of biologics versus conventional systemic agents were 2.2 for PASI, 3.5 for DLQI, and 0.11 for EQ-5D. The estimated incremental benefits of biologics for the subgroup of patients not responding to their conventional systemic agent were even greater.

CONCLUSION: Register-based research complements knowledge from randomized controlled trials regarding relative effectiveness in clinical practice. This information can be used to support health care decision making. This research suggests that there is both under- and overtreatment with biologics in Swedish clinical practice. Reallocation of biologics to more severe cases of psoriasis could improve overall health in the total patient population.

The introduction of biologics has changed treatment patterns as well as costs in patients with psoriasis. To estimate direct and indirect costs of the psoriasis population in Sweden, and to analyse changes in costs between 2006 and 2009. The study population was identified in national registers. Direct costs included health care visits with primary psoriasis diagnoses in specialist care and drugs relevant for treating psoriasis. Productivity loss, including long-term sick leave and disability pension, was estimated as the difference compared to matched controls from the general population. Total direct cost (in SEK 2009 price level) increased from SEK 348 million in 2006 to SEK 459 million in 2009, whereas the total productivity loss decreased from SEK 1,646 to 1,618 million between 2006 and 2009. Although direct costs, especially for biologic agents, have increased for patients with psoriasis over time, this study indicates that costs related to productivity loss are still more substantial.

Psoriasis is a chronic, immunological and systemic disease with an estimated prevalence of about 2-3 percent. Psoriasis is associated with the joint disease psoriasis arthropathy. There are several treatments options available for psoriasis and patients with moderate to severe psoriasis generally need systemic agents. In 2004 biologics were introduced for patients with moderate to severe psoriasis in Sweden.

The overall objective of this thesis was to assess the relationship between Health Related Quality of Life (HRQOL) and clinical outcome measures in psoriasis patients, to analyse the effectiveness of biologics in psoriasis in everyday clinical practice and to explore how costs of the psoriasis population changed after the introduction of biologics in Sweden.

Methods: Research was based on national administrative registers and PsoReg, the Swedish registry for systemic treatment of psoriasis. In a cross-sectional study (paper I) the three outcome measures: the generic HRQOL measure EQ-5D, the dermatology specific HRQOL measure the Dermatology Life Quality Index (DLQI) and the clinical measure of skin involvement, Psoriasis Area and Severity Index (PASI), were analysed by demographic characteristics. The generic EQ-5D among psoriasis patients was compared to previously published values for the general population in Sweden. Relationships between measures were examined with correlation tests and regression analysis. A longitudinal study included patients registered in PsoReg who switched to a biologic agent for the first time during registration (paper II). The three outcomes EQ-5D, DLQI, and PASI were analysed before and after switch in the overall patient group and in subgroups. The relative effectiveness of continuing with the standard care of conventional treatment compared to switching from standard care to biologics was analysed in patients with moderate to severe psoriasis (paper III). Patients in PsoReg were matched with propensity scores and average treatment effects were estimated. The estimated outcomes were the change of EQ-5D, DLQI, and PASI. Patients were identified in national registers at the National Board of Health and Welfare when analysing costs; either by a registration of a psoriasis diagnosis in the national patients register and/or by a registration in the prescribed drugs register of a topical treatment with calcipotriol, a substance which has the indication psoriasis only (paper IV). Direct costs included patients’ visits in specialist health care and prescribed drugs used for psoriasis treatment, retrieved from the national patients register and the prescribed drugs register, respectively. Indirect costs included productivity loss in terms of sick leave and disability pension, which estimated as excess costs compared to controls. Controls were selected from the normal population and matched on sex, age and municipality. Productivity loss was estimated based on data from the Longitudinal integration database for health insurance and labour market studies at Statistics Sweden.

Results: Patients with moderate to severe psoriasis had significantly lower HRQOL in EQ-5D than the general population (paper I). Women rated their HRQOL lower than men, even though men had more severe clinical skin involvement than women. (paper I). The generic measure EQ-5D and the dermatology-specific DLQI had moderate correlations whereas EQ-5D had low correlation with the clinical measure PASI (paper I). Patients who switched to a biologic agent during registration in PsoReg had significant improvements in all outcomes (paper II). Patients who fulfilled the criteria for moderate to severe psoriasis had the highest benefits of the biologic agents (paper II). The matched conventionally and biologically treated patients with moderate to severe psoriasis were essentially equal in important observable variables (paper III). The subgroup of patients not responding to conventional treatment had high potential benefits of biologic agents (paper III). Individuals with psoriasis had sick leave and disability pension to a larger extent than their matched controls (paper IV). Direct costs increased, whereas the indirect costs of productivity loss decreased between 2006 and 2009 (paper IV).

Conclusion: Psoriasis is associated both with direct costs and indirect costs, and it has a negative impact on patients’ HRQOL. When evaluating psoriasis treatments and making decisions about treatment guidelines, both generic, dermatology-specific HRQOL measures, and clinical measures are necessary; as they answer to different needs. Although dependent on data quality, generalisability, and current pricing, results suggest that conventional treatments are suitable as first line and biologic agents as second line treatment. Results indicate that the different types of systemic treatments are not allocated optimally among patients with psoriasis in Swedish clinical practice.

Background: As moderate to severe psoriasis is a systemic disease with large effects on health related quality of life (HRQOL) generic measures that include overall health, not only skin involvement, are necessary. The knowledge about the relationship between the generic preference-based EQ-5D and dermatology-specific measures in psoriasis is limited.

Objective: The objective was to analyse EQ-5D, the Dermatology Life Quality Index (DLQI) and Psoriasis Area and Severity Index (PASI) in patients with moderate to severe psoriasis in Swedish clinical practice by demographic characteristics, to compare EQ-5D among patients to Swedish population values, and to analyse the relationships between EQ-5D, DLQI and PASI.

Methods: This observational cohort study was based on PsoReg, the Swedish National Registry for Systemic Treatment of Psoriasis. EQ-5D among psoriasis patients was compared to a defined general population in Sweden, retrieved from a previous study. Relationships between measures were examined with correlation tests and regression analysis.

Results: 2450 patients (men n=1479, women n=971) were included. Median EQ-5D, DLQI and PASI was 0.769, 4 and 4.7, respectively. Psoriasis patients had a significantly lower EQ-5D compared to the defined general population. EQ-5D correlated moderately with DLQI (-0.55) and weakly with PASI (-0.25) (p<0.001).

Conclusions: When assessing psoriasis treatments and making decisions about treatment guidelines and resource allocation, EQ-5D, DLQI and PASI provide a useful set of complementary tools, answering to different needs. If EQ-5D is not included in the original trial the second best option in cost-effectiveness studies is to use mapping between DLQI and EQ-5D.

Background: Although clinical studies have shown efficacy of biological agents in moderate to severe psoriasis, observational studies of real-world effectiveness are rare.

Objective: To analyse the psoriasis area and severity index (PASI) and quality of life by the EQ-5D questionnaire and dermatology quality of life index (DLQI) in psoriasis patients who switched from conventional systemic treatment to biological agents in clinical practice. Furthermore, to analyse patient groups with the highest benefit of biological agents.

Methods: Longitudinal, observational study based on the Swedish National Registry for Systemic Treatment of Pso-riasis, PsoReg. Outcomes of biological-naïve patients who switched to a biological agent (n = 267) were analysed before switch and at the first follow-up.

Results: Patients significantly improved in EQ-5D, DLQI and PASI (p < 0.001). Patients with DLQI ≥10 and/or PASI ≥10 had the greatest benefits from biological agents in terms of EQ-5D.

Conclusions: Patients with moderate to severe psoriasis benefit from biological agents in clinical practice; the patients with the highest benefits were those with high pretreatment PASI and DLQI scores.