ARTICLE
Auteur(s) : Ines
Schäfer, Jana Hacker, Stephan Jeff Rustenbach, Marc Radtke,
Nadine Franzke, Matthias Augustin
CVderm – German Center for Health Services Research
in Dermatology, Research Group Health Economics
and Quality of Life Research, Department
of Dermatology and Venereology, University Clinics
of Hamburg, Martinistraße 54, D-20246 Hamburg, Germany
accepté le 3 Septembre 2009
The therapeutic spectrum of psoriasis vulgaris is broad and
management of the disease is varied [1, 2]. Over recent years, the
need to improve the structure of psoriasis therapy, to define
treatment goals and to measure treatment outcomes by means of
parameters of clinical severity and Quality of Life has intensified
[3, 4]. Of particular importance is the recording of outcomes of
therapies with systemic drugs and biologics in accordance with
valid treatment standards [5]. These essentially allow for the
measurement of results by means of the Psoriasis Area and Severity
Index (PASI) [6]. In particular, improvements in the PASI of about
50%, 75% or 90% in comparison to baseline are regarded as markers
of effective treatment [7, 8].
It is yet to be shown that the PASI value fails to correlate
strongly with the patient’s state of health as well as with her/his
Quality of Life [9]. Subjective assessments of the severity of the
disease can turn out in similar clinical findings rather
differently. Additionally, the severity of the psoriasis [10] and
the respective living circumstances, age [11], stress, and mental
attributes [12, 13] have so far been identified as influence
factors for the subjectively perceived burdens caused by the
disease. The expectations and goals that patients associate with
psoriasis treatments, as well as the assessment of treatment
benefits, are appropriately complex and, to a great extent, unique
to the individual [14].
Taking this into account, it is essential to supplement the
assessment of a course of therapy via PASI with a patient-reported
parameter [15]. Also, the PASI threshold value as a measure of
“response” should exhibit sufficient relevance to patients. In
preliminary studies, the correlation between a change in PASI
(∆PASI) and patient-reported outcomes appeared inconsistent. Touw
et al. [16] found only a moderate correlation between ∆PASI
and the health-related Quality of Life (Dermatology Life Quality
Index, DLQI); Revicki et al. [17] saw significant association
of ∆PASI with the DLQI as well as with the Short Form 36 (SF-36
total score). However, a strong effect was found in an improvement
of PASI-Scores from 90% or 100%. In contrast, the correlation
between ∆PASI and the changes in various psychological scores was
not significant [13].
In addition to Quality of Life, the patient-defined benefit of
therapy is a further independent factor for external validity of
∆PASI, one that has not been analyzed in this context so far.
The patient-defined treatment benefits differ considerably in
concept from the construct of Quality of Life. The Quality of Life
instruments normally do not cover the broad and individual spectrum
of patient-relevant benefits and provide no possibilities for
preference formation [18]. Furthermore, Quality of Life parameters
are based upon a global assessment of the areas of life, whereas
the ascertainment of treatment benefits applies specifically to the
effects of a defined therapy and thereby suggests a causal
attribution. It is as yet unclear how relevant the improvements in
PASI-scores are for the patient her/himself. In particular, there
is a lack of data on the correlation between personal assessment of
treatment benefits and the clinical outcomes PASI-50 and
PASI-75.
Study questions
- 1. To what degree does the cross-sectional PASI
correlate with patient-reported outcomes?
- 2. To what extent are PASI-50 and PASI-75 reflective of
the health-related Quality of Life as well as the treatment
benefits experienced by the patients?
Materials and methods
A prospective observational study with two collection dates was
conducted. The study population was 100 consecutive patients who
were treated as outpatients in the study period from April to
September 2007 in the Department of Dermatology at the University
Clinics of Hamburg. Inclusion criteria were age of at least 18
years, as well as a clinically confirmed diagnosis of psoriasis
vulgaris. The treatments were carried out according to clinical
standards and had no bearing on the patient recruitment of the
study.
Data collection
The attending physicians and the patients filled out standardised
questionnaires at the start (t1) and towards the end of treatment
(t2). On the physician’s questionnaire the following clinical and
treatment-related variables were recorded: attributes of the
psoriasis, prior therapies and co-morbidity, and the existence or
indication of psoriatic arthritis. In addition, the PASI was
determined during both data collection dates. With the patient’s
questionnaire at t1, data were obtained on socio-demographic
characteristics, burden of disease, general state of health, and
health care utilization. The DLQI was filled out as a parameter of
health-related Quality of Life as well as the Patient Needs
Questionnaire (PNQ) as the first part of the Patient Benefit Index
(PBI) for assessment of patient-defined treatment needs. The
patient questionnaire at the second collection date contained
questions on the burden of psoriasis and its treatment, as well as
the health scales and the DLQI. Additionally, a general evaluation
of therapies, as well as the second part of the PBI, the Patient
Benefits Questionnaire (PBQ) were recorded.
Measuring instruments
Psoriasis Area and Severity Index (PASI). The PASI score [19] is
the most widely used index measure of psoriasis severity,
evaluating the area, erythema, scaliness and thickness of the
plaques. The PASI-score ranges from 0 to 72. The parameters PASI-50
and PASI-75 correspond to an improvement of the PASI of about 50%
and 75%, respectively, compared to the baseline score.
Patient Benefit Index (PBI). For the assessment of
patient-defined treatment benefits, the PBI was used. This is an
instrument developed and validated specifically for the field of
dermatology [20, 21]. The basic foundation step is the
pre/post-data-collection. Prior to therapy, the individually
perceived needs (Patient Needs Questionnaire, PNQ) are obtained.
For each of the 25 standardized items the patient rates its
importance by means of a 5-point Likert Scale ranging from 0 (not
important at all) to 4 (very important). After therapy, the degree
to which these benefits have been achieved is assessed by the same
item list, on the Patient Benefit Questionnaire (PBQ), on a 5-point
scale from 0 (did not help at all) to 4 (helped very much). As a
single outcome parameter, the Patient Benefit Index (PBI) is
computed by weighting the PBQ items with their respective PNQ
items. The PBI ranges from 0 (no benefit) to 4 (maximum benefit).
PBI ≥ 1 is adopted as a cut-off value for a “relevant treatment
benefit”.
Single questions for treatment-evaluation. With a set of 8
items, patient satisfactions and the effects of the treatment in
her/his living situation were obtained on t2. For the following
analyses, the two questions which were generally formulated and are
thus relevant to all forms of therapy, were used: 1) “Were your
expectations met by therapy?”; and 2) “Is the condition of the skin
achieved sufficient for you?”, Both questions were answered on a
scale of 1 (completely) to 4 (not at all).
DLQI. For the measurement of disease-specific (dermatological)
Quality of Life, the 10-item-scale of the DLQI [22] was applied.
The cumulative value of the DLQI ranges from 0 to 30. A higher
DLQI indicates a more intense impairment due to the skin disease.
On a score that is lower than 2, it is assumed that the QoL is not
restricted.
EuroQol (EQ-5D). The general health-related Quality of Life was
measured with the Visual Analog Scale (VAS) of the EQ-5D [23], in
which the patient rates her/his current state of health on a scale
ranging from 0 (“worst conceivable state of health”) to 100 (“best
conceivable state of health”).
Statistical analyses
In the descriptive analyses, the absolute and percentage
frequencies are presented for categorical data; for continuous
variables, mean and standard deviation are given. The validated
scales (PASI, PBI and DLQI) were each analyzed according to their
standardised syntax. Changes in the PASI score between the
collection dates t1 and t2 were calculated as continuous values
(∆PASI in %) as well as threshold values PASI-50 and PASI-75.
Computations were carried out (as with changes in DLQI and in the
values of the health scale of the EQ-5D), as percentage changes of
the baseline values (t1). For the analysis of the correlation
between PASI and patient-reported outcomes (each with continuous
variables), Spearman Rank Correlation Coefficients were calculated
(level of significance α ≤ 0.05, two-sided test). The distribution
of the parameters PASI<50, PASI-50 and PASI-75 were analyzed
according to the dichotomous values of DLQI, PBI and the single
questions on treatment-evaluation. The data analyses were carried
out with SPSS 15.0 for Windows®.
Results
Available for the evaluation of the first collection date were data
from 93 patients (38% female), of whom 80 (39% female) also took
part in the second data collection (table
1). The mean time-lag from t1 to t2, and thus the period of
treatment and observation, was 42.5 days (± 17.0; Median
38.5).
On average, the PASI score improved about 62% (± 24.9), and
with the exception of one patient, the PASI of t2 was in each case
lower than that of t1. 40% of all patients exhibited an improvement
of at least 50%, and 32.5% of patients, an improvement of at least
75% in PASI. The general state of health represented by the visual
analog scale of the EQ-5D increased on average from a value of 54.4
(max 100) at t1 to 69.0 at t2. With a DLQI total score of 5.6, the
impairment of the Quality of Life of t2 was considerably lower than
that of t1 (DLQI 9.7). On a scale of 0 (treatment did not help at
all) to 4 (helped a lot), the mean value of PBI was 2.3
(± 1.3); 76.3% of the patients attained a PBI of ≥ 1.0.
On the general questions about treatment satisfaction, 61.3% of
the patients specified that their expectations were met completely
or predominantly. Slightly more than half of the patients were
completely or predominantly satisfied with the achieved condition
of the skin; 16.3% were not satisfied at all (table 2). In a cross-section, a minor correlation
between PASI and the patient-defined outcomes existed in both
collection dates (table 3): the
correlation of PASI and DLQI was R = 0.24 on t1 and R = 0.36 on t2.
A similar association appeared for the PASI and the health
scales of the EQ-5D: here, the correlation coefficient in each case
was about R = – 0.30. Thus, a higher PASI is associated with a
more intense impairment of the dermatological Quality of Life and
with a lower assessment of the general state of health; though the
correlation was only moderate in each case.
The average improvement in PASI score (∆PASI) was correlated
moderately highly with the PBI (R = 0.45), as well as with the
change of DLQI (R = 0.50). There was no existing correlation with
the increase on the general health scale of the EQ-5D (R = 0.10)
(table 4).
The distribution of the three PASI groups, PASI<50, PASI-50
and PASI-75, on the patient-reported outcomes (table 5, figures 1, 2), shows that
the percentage of patients who evaluated the outcome positively
increased with improvements in PASI scores. Nevertheless, relevant
percentages of unsatisfied patients in groups with high PASI
improvement were found in each case, as well as a comparatively
high percentage of satisfied patients in groups with low PASI
improvement.
While most patients with PASI-75 specified that their
expectations of the treatment were completely or predominantly met,
this applied to only slightly more than half (53.1%) of the
patients in the group with PASI-50. For the other half (46.9%), the
expectations were not all met or somewhat met. In the group with
the lowest clinical treatment success (PASI<50, however, 36.4%
of the patients answered that their expectations of the treatment
were met (figure
1). More than half of the patients with PASI-50 and 15.4%
of the patients with PASI-75 were not satisfied with the achieved
condition of the skin after therapy. On the other hand, 36.4% of
the patients who did not reach PASI-50 were satisfied with their
skin-condition (figure
2).
A DLQI score lower than 2 implies that the psoriasis does not
impair patient’s Quality of Life. This applied for only 18.8% of
the PASI-50 and for 34.6% of the PASI-75 group after therapy.
Accordingly, 65% of the patients with an increase of the PASI of
about 75% further experienced restrictions in their Quality of Life
due to the psoriasis (table 5). In the
groups with PASI-50 and PASI-75, 62.5% and 42.3% of the patients,
respectively, attained no improvement of the DLQI of at least 5
score points. Slightly more than half of the patients in the group
under PASI-50, 75.0% of the patients with PASI-50 and virtually all
patients with PASI-75 had a substantial treatment benefit, defined
by a PBI≥1. This implies that a quarter of the PASI-50 patients
subjectively experienced no personally relevant treatment
benefits.
Table 1 Characteristics of study population, PASI and
patient reported outcomes t1 (before therapy) and t2 (after
therapy)
|
t1
|
t2
|
|
Patients
|
n = 93
|
n = 80
|
|
Women
|
37.6%
|
38.8%
|
|
Age
|
49.3 (14.1)
|
50.1 (14.6)
|
|
PASI (range 0-72)
|
13.7 (9.5)
|
5.5 (5.8)
|
|
VAS EQ 5-d (range 0-100)
|
54.4 (26.3)
|
69.0 (22.7)
|
|
DLQI (range 0-30)
|
9.7 (6.5)
|
5.6 (5.2)
|
|
Duration of therapy (t1-t2)
|
-
|
42.5 (17.0)
|
|
PBI (range 0-4)
|
-
|
2.3 (1.3)
|
|
PBI ≥ 1
|
-
|
76.3%
|
|
PASI < 50 (%)
|
-
|
27.5
|
|
PASI-50 (%)
|
-
|
40.0
|
|
PASI-75 (%)
|
-
|
32.5
|
|
∆PASI (% diff. t1-t2)
|
-
|
62.0 (24.9)
|
Table 2 Distribution of answers to global questions on
therapy satisfaction (n = 80 patients)
|
Expectations met by therapy
|
n
|
%
|
|
completely
|
18
|
22.5
|
|
predominantly
|
31
|
38.8
|
|
somewhat
|
25
|
31.3
|
|
not at all
|
6
|
7.7
|
|
Achieved conditions of the skin is sufficient
|
|
|
|
completely
|
5
|
6.3
|
|
predominantly
|
39
|
48.8
|
|
rather not
|
23
|
28.8
|
|
definitely not
|
13
|
16.3
|
Table 3 Cross-sectional correlations between PASI and
patient-reported outcomes at t1 and t2
|
t1
|
t2
|
|
PASI
|
PASI
|
|
n
|
R
|
p
|
n
|
R
|
p
|
|
DLQI
|
80
|
0.24
|
0.03
|
80
|
0.36
|
0.00
|
|
Health-scale EQ-5D
|
80
|
-0.30
|
0.02
|
77
|
-0.31
|
0.01
|
|
PBI
|
-
|
-
|
-
|
80
|
0.41
|
0.00
|
Table 4 Correlations of improvement in PASI-Score from
t1 to t2 (∆ PASI) with change in patient-reported outcomes
|
∆ PASI
|
|
n
|
R
|
p
|
|
∆ DLQI
|
73
|
0.50
|
0.00
|
|
PBI
|
80
|
0.45
|
0.00
|
|
∆ EQ-5D Health-scale
|
74
|
0.10
|
0.48
|
Table 5 PASI response groups by patient defined
outcomes (% from PASI-group)
|
∆ PASI
|
|
< PASI-50
|
PASI-50
|
PASI-75
|
|
Expectations met completely/predominantly
|
36.4
|
53.1
|
92.3
|
|
Expectations met somewhat/not at all
|
63.6
|
46.9
|
7.7
|
|
Achieved conditions of the skin: completely/predominantly
sufficient
|
36.4
|
43.8
|
84.6
|
|
Achieved conditions of the skin: rather not/definitely not
sufficient:
|
63.6
|
56.3
|
15.4
|
|
DLQI < 2
|
18.2
|
18.8
|
34.6
|
|
DLQI ≥ 2
|
81.8
|
81.3
|
65.4
|
|
∆ DLQI < 5
|
86.4
|
62.5
|
42.3
|
|
∆ DLQI ≥ 5
|
13.6
|
37.5
|
57.7
|
|
PBI ≥1
|
54.5
|
75.0
|
96.2
|
|
PBI <1
|
45.5
|
25.0
|
3.8
|
Discussion
PASI-50 and PASI-75 are internationally the most important
parameters for assessment of the severity of psoriasis.
Shortcomings in their validity have previously been found in terms
of inter-rater variability, construct and external validity [24] as
well as with regard to their significance for treatment concepts
[25]. This prospective study with ambulant psoriasis patients
indicates a correlation between the objective clinical severity
parameter PASI on the one hand, as well as the disease-specific
Quality of Life and the patient-defined benefits in the psoriasis
treatment on the other. There was no association with the general
state of health. However, the correlations between PASI and the
patient-relevant outcomes Quality of Life and treatment benefits
were, on average, only mildly correlated. The extent of the changes
in these items over the period of treatment indicates a somewhat
more significant, but moderately high correlation with the PASI.
The parameters PASI-50 and PASI-75, established as threshold
values of psoriasis-severity measurement, were likewise positively
associated with patient-defined outcomes, but they reflected them
incompletely. Thus, about half of the patients with PASI-50 did not
see their expectations of the treatment met, or were not satisfied
with the condition of their skin after treatment. A quarter of
these patients experienced no benefits from the therapy. Of the
patients with PASI-75, 15% were not satisfied with the condition of
their skin, and a clinically relevant restriction in Quality of
Life due to the psoriasis still existed for more than half of them.
In contrast, a relevant percentage in each case of patients who did
not attain PASI-75 or PASI-50 reported a high level of satisfaction
or a subjectively significant treatment benefit.
The relatively short average observation time (42.5 days) in
this study was chosen intentionally in order to give more variance
in the outcome parameters. The idea was that after a longer
observation period under routine conditions, too many patients
might have reached PASI 75 and only a few would have remained in a
moderate-to-poor skin condition. As intended, a fair distribution
of delta PASI has resulted (table 1).
With this approach, however, we cannot rule out that after a longer
treatment period a response shift may have occurred.
Limitations in terms of the interpretation of the results might
have arisen from the small sample size of this pilot study. Thus,
stratification, for example by current therapies, was not possible.
Moreover, only a few cases were found in several subgroups,
particularly in the bottom area of the scale of the general
questions for treatment and therapy satisfaction. For this reason,
further differentiation of the PASI grouping, such as the
representation of PASI-90, could not be carried out. Response
statistics could not be conducted during the recruitment of
patients which was carried out consecutively over a definite time
period. Moreover, there was no available information about
non-participants, so that a selection bias (internal validity) or a
restriction of the generalizability of results (external validity),
due to selective participation of patient groups, could not be
excluded.
As desired, there was in fact a fair distribution of delta PASI
(table 1). As a reference for the
evaluation of results, the national psoriasis study PsoHealth [26]
can be applied. In that survey, representative data on the
health-care situation of n = 2,009 psoriasis patients were
collected within a network of 130 dermatological practices and
outpatient clinics. The age and sex structure of this extensive
sample conforms largely to the age and sex distribution of our
study. In PsoHealth, average PASI and DLQI lie in-between the
determined values for t1 and t2 (PsoHealth: PASI = 10.1; DLQI =
7.5; health scale EQ-5D = 64.5, PBI = 2.5). In this respect, this
study conforms to expectations, since PsoHealth was a
cross-sectional study with patients in different stages of
treatment, whereas the data presented here were collected before
and at the end of a therapy. The comparison of these results with
the extensive study supports the assumption that adequate validity
is given for this pilot-study.
The findings for the correlation of PASI and patient-reported
outcomes are verified by the PsoHealth data, which also show
moderate to weak associations: the correlation coefficient of PASI
and DLQI was R = 0.39, R = – 0.24 for PASI and PBI and R =
– 0.34 for PASI and EQ-5D in PsoHealth. Other longitudinal
studies have resulted in similarly low associations between ∆PASI
and ∆DLQI (R = 0.4) [16] such as in the study presented here (R =
0.50). Effects were similar when the two parameters, Body Surface
Area (BSA) as clinical measurement, and Willingness to Pay, as
patient-reported outcome, were used instead of the PASI [27], where
no relevant correlation appeared for these two parameters. Studies
on other dermatological diagnoses point out that the moderate to
weak correlation between the clinical measures of disease severity
and patient-relevant outcomes exists not only for psoriasis, but
also for atopic dermatitis [28] and acne [29].
The finding, that the correlation between PASI and
disease-specific Quality of Life (DLQI), was stronger than that
between PASI and general state of health (EQ-5D), conforms to
expectations and is identical to the results of Revicki et al.
[17] and other studies [30]. Clinical severity of psoriasis,
disease-specific Quality of Life, as well as patient-reported
treatment-needs and -benefits are parameters that are associated
with each other, but are based on differing concepts and reflect
specific aspects of treatment outcomes. In each case, they should
be considered in the evaluation of psoriasis care. The results of
this pilot study confirm the need and the feasibility of further
research. For this purpose, a comprehensive multi-center study on
ambulant and hospital-patients is projected.
Acknowledgements
No financial support was given for this study. The authors declare
no conflict of interest.
References
1 Gulliver W. Long-term prognosis in patients with psoriasis.
Br J Dermatol 2008; 159 (Suppl 2): 2-9.
2 van de Kerkhof PC. Options for the treatment of
psoriasis: a multifactorial approach. Clin Dermatol 2008; 26:
419-23.
3 Ortonne JP. What are objectives of moderate to severe
psoriasis treatment? Ann Dermatol Venereol 2008; 135 (Suppl 5):
S281-S284.
4 Augustin M, Lange S, Wenninger K,
Seidenglanz K, Amon U, Zschocke I. Validation of a
comprehensive Freiburg Life Quality Assessment (FLQA) core
questionnaire and development of a threshold system. Eur J Dermatol
2004; 14: 107-13.
5 Boehncke WH, Adebajo A, Cauli A, Nash P,
Salvarani C, Kavanaugh AF. Initiative for quality in
psoriasis and psoriatic arthritis. J Rheumatol 2008; 35:
1431-3.
6 Nast A, Kopp IB, Augustin M, Banditt KB,
Boehncke WH, Follmann M, et al. Evidence-based (S3)
guidelines for the treatment of psoriasis vulgaris. J Dtsch
Dermatol Ges 2007; 5: 1-119.
7 Sterry W, Barker J, Boehncke WH, Bos JD,
Chimenti S, Christophers E, et al. Biological
therapies in the systemic management of psoriasis: international
consensus conference. Br J Dermatol 2004; 151 (Suppl 69): 3-17.
8 Callen JP, Krueger GG, Lebwohl M,
McBurney EI, Mease P, Menter A, et al. AAD
consensus statement on psoriasis therapies. J Am Acad Dermatol
2003; 49: 897-9.
9 Reich K, Griffiths CE. The relationship between
quality of life and skin clearance in moderate-to-severe psoriasis:
lessons learnt from clinical trials with infliximab. Arch Dermatol
Res 2008; 300: 537-44.
10 Canpolat F, Cemil BC, Eskioğlu F,
Akis HK. Is facial involvement a sign of severe psoriasis? Eur
J Dermatol 2008; 18: 169-71.
11 Krueger G, Lebwohl M, Menter A, Stern RS,
Rolstad T. The impact of psoriasis on quality of life. Arch
Dermatol 2001; 137: 280-4.
12 Mease PJ, Menter MA. Quality of life issues in
psoriasis and psoriatic arthritis: outcome measures and therapies
from a dermatological perspective. J Am Acad Dermatol 2006; 54:
685-704.
13 Consoli SM, Rolhion S, Martin C, et al.
Low levels of emotional awareness predict a better response to
dermatological treatment in patients with psoriasis. Dermatology
2006; 212: 128-36.
14 Zschocke I, Hammelmann U, Augustin M.
Therapeutic benefits in dermatological therapy. Evaluation of
therapy from the physician’s und patient’s perspective in psoriasis
and atopic dermatitis. Hautarzt 2005; 56: 839-46.
15 Grob JJ. Why are quality of life instruments not
recognized as reference measures in therapeutic trials of chronic
skin disorders? J Invest Dermatol 2007; 127: 2315-22.
16 Touw CR, Hakaart-van-Roijen L, Verboom P,
Rutten FFH, Finlay A. Quality of life and clinical
outcome in psoriasis patients using intermittent cyclosporine. Br J
Dermatol 2001; 144: 967-72.
17 Revicki DA, Willian MK, Menter A,
Saurat JH, Harnam N, Kaul M. Relationship between
clinical response to therapy and health-related quality of life
outcomes in patients with moderate to severe plaque psoriasis.
Dermatology 2008; 216: 260-70.
18 Dijkers MP. Individualization in quality of life
measurement: instruments and approaches. Arch Phys Med Rehabil
2003; 84 (4 Suppl 2): S3-S14.
19 Fredriksson T, Pettersson U. Severe psoriasis--oral
therapy with a new retinoid. Dermatologica 1978; 157: 238-44.
20 Augustin M, Gajur A, Reich C,
Rustenbach S, Schaefer I. Benefit evaluation in vitiligo
treatment: Development and validation of a patient-defined outcomes
questionnaire. Dermatology 2008; 217: 101-6.
21 Augustin M, Reich C, Schaefer I,
Zschocke I, Rustenbach SJ. Development and validation of
a new instrument for the assessment of patient-defined benefit in
the treatment of acne. J Dtsch Dermatol Ges 2008; 6: 113-20.
22 Finlay AY, Khan GK. Dermatology Life Quality Index
(DLQI)--a simple practical measure for routine clinical use. Clin
Exp Dermatol 1994; 19: 210-6.
23 Hurst NP, Kind P, Ruta D, Hunter M,
Stubbings A. Measuring health-related quality of life in
rheumatoid arthritis: validity, responsiveness and reliability of
EuroQol (EQ-5D). Br J Rheumatol 1997; 36: 551-9.
24 Jacobson CC, Kimball AB. Rethinking the Psoriasis
Area and Severity Index: the impact of area should be increased. Br
J Dermatol 2004; 151: 381-7.
25 van de Kerkhof PC, Kragballe K, Austad J,
Berth-Jones J, Cambazard F, de la Brassinne M,
et al. Psoriasis: severity assessment in clinical practice.
Conclusions from workshop discussions and a prospective multicentre
survey of psoriasis severity. Eur J Dermatol 2006; 16: 167-71.
26 Augustin M, Reich K, Reich C, Purwins S,
Jeff Rustenbach S, Schäfer I, et al. Quality of
psoriasis care in Germany - results of the national study PsoHealth
2007. J Dtsch Dermatol Ges 2008; 6: 640-5.
27 Delfino Jr M, Holt EW, Taylor CR,
Wittenberg E, Qureshi AA. Willingness-to-pay stated
preferences for 8 health-related quality-of-life domains in
psoriasis: A pilot study. J Am Acad Dermatol 2008; 59:
439-47.
28 Salek MS, Finlay AY, Luscombe DK,
Allen BR, Berth-Jones J, Camp RD, et al.
Cyclosporin greatly improves the quality of life of adults with
severe atopic dermatitis. A randomized, double-blind,
placebo-controlled trial. Br J Dermatol 1993; 129: 422-30.
29 Demircay Z, Seckin D, Senol A, Demir F.
Patient’s perspective: an important issue not to be overlooked in
assessing acne severity. Eur J Dermatol 2008; 18: 181-4.
30 Feldman SR, Menter A, Koo JY. Improved health
related quality of life following a randomized controlled trial of
alefacept treatment in patients with chronic plaque psoriasis. Br J
Dermatol 2004; 150: 317-26.
|
Printable version
Version PDF
