A description of treatment patterns of psoriasis by medical providers and disease severity in US women

Abstract

Background:

Studies on treatment patterns of psoriasis are valuable to evaluate how efficiently individuals with psoriasis are treated and may facilitate improved outcomes for these patients.

Objective:

To describe treatment patterns of psoriasis among US women.

Methods:

In the Nurses’ Health Study II (NHS II), a prospective study of female nurses, 2107 women reported to have a diagnosis of psoriasis made by a clinician. We sent them the Psoriasis Screening Tool-2, a validated diagnostic tool for psoriasis, which queries age at diagnosis, treatments, type of psoriasis lesions, body surface area involved, and the provider who made the diagnosis.

Results:

A total of 1382 women completed and returned the survey, with 1243 of them validated for having psoriasis. 30% of the patients were diagnosed by non-dermatologists. 79% of the patients reported mild, 17% moderate and 4% severe disease. Psoriasis phenotypes were as follows: plaque 41%, scalp 49%, inverse 27%, nail 22% and palmoplantar 15%. Treatment patterns for mild psoriasis were as follows: only topical treatment 58%, systemic therapy and/or phototherapy 16% and no treatment 26%. Treatment patterns for moderate-to-severe disease were as follows: only topical treatment 42%, systemic therapy and/or phototherapy 47% and no treatment 11%.

Conclusion:

The majority of women in NHS II with psoriasis have mild disease. A large proportion of psoriasis patients were diagnosed by non-dermatologists. More than half of people with moderate-to-severe disease received no treatment or only topical medications. A considerable percentage of people with psoriasis reported phenotypes other than chronic plaque psoriasis.

Introduction

Psoriasis is a common chronic inflammatory skin disease with a worldwide prevalence of 1–3%.^1–4 Plaque psoriasis is the most common phenotype which affects 80–90% of patients.^5,6 Other phenotypes include scalp, palmoplantar, nail and inverse disease.⁷ Psoriasis is associated with an increased risk of comorbidities (e.g. anxiety, depression, cardiovascular disease, obesity, metabolic syndrome, malignancies, inflammatory bowel diseases and psoriatic arthritis) and death.^1,5,8–10 It also has a profound negative impact on patients’ emotional, social and physical quality of life (QoL).¹¹ Currently there is no cure for psoriasis and available treatments provide symptomatic relief. Four types of treatment exist: topical medications, phototherapy, traditional systemic medications and targeted systemic therapies (biologics).⁵ Today, with increasing usage of biologics, achieving 90% or 100% reduction in symptoms has become an achievable goal.¹² Choices of treatments are customized to the patient and are influenced by factors such as disease severity, lesion characteristics / location, comorbidities, insurance coverage, safety and patients’ preferences.^5,12

Effective treatment of psoriasis is of paramount importance owing psoriasis is not just a cosmetic problem and even patients with limited involvement often find their disease a large problem in everyday life.⁴ Some specific phenotypes of psoriasis such as inverse psoriasis, nail disease, palmoplantar involvement and scalp disease may have a profound negative impact on a patient’s QoL. Despite the small surface area commonly affected by psoriasis in these locations, patients usually demonstrate disproportionate levels of physical impairment and emotional distress, however, with limitations in current therapies, many patients do not receive proper or adequate treatment.¹³

Therefore, understanding treatment patterns of psoriasis patients in the real world is important to evaluate how efficiently psoriasis patients are treated and facilitate improved outcomes. Literature on treatment patterns of psoriasis is limited. ¹⁴ In this study, we present patterns of treatment used by medical providers for women with psoriasis in the Nurses’ Health Study II cohort study.

Methods

Study participants are from Nurses’ Health Study II (NHS II), a large prospective cohort study established in 1989 with 116,430 female nurses aged 25–42 years.^9,15 Data on lifestyle factors and medical history are collected by questionnaire biennially.

This study was approved by the Institutional Review Board of Brigham and Women’s Hospital. Participants’ completion and return of the self-administered questionnaires is considered informed consent.

In 2005, 2009 and 2013, NHS II participants were asked whether they have ever been diagnosed with psoriasis by a clinician. Psoriasis Screening Tool (PST) was used to validate the diagnosis of psoriasis reported in 2005.⁷ In 2016, we sent the psoriasis screening tool-2 (PST-2) to NHS II participants who reported a diagnosis of psoriasis in 2009 or 2013, in order to validate their diagnosis and collect more disease-specific information.

PST is a self-administered questionnaire inquires about being diagnosed with psoriasis by different medical providers and the phenotypes of psoriasis using pictures. A pilot study showed a sensitivity of 99% and a specificity of 94% for PST for diagnosing psoriasis.¹⁶ PST-2 is a more thorough version of the original PST questionnaire and includes questions from PST with additional questions on age at disease diagnosis, type and duration of treatments and the involved body surface area (BSA) at its worst, measured by 1%for each palm. This method was previously been studied by Dommasch et al. and was reported as a reliable, valid and responsive measure of BSA affected by psoriasis.¹⁷

We classified psoriasis severity as mild (< 3% BSA affected), moderate (3–10% BSA), and severe (>10% BSA).^18,19 Treatments were categorized as topical, ultraviolet (UV) phototherapy and systemic including traditional medications (methotrexate, cyclosporine, and acitretin) and targeted systemic therapies (etanercept, adalimumab, infliximab, golimumab, certolizumab pegol, and ustekinumab). We calculated descriptive statistics to summarize the data.

Results

A total of 2107 women in NHSII reported ever being diagnosed with psoriasis by a clinician. Among these, 1,382 women (66% response rate) completed and returned PST-2. Using PST-2, 1243 of them had validated diagnosis of psoriasis with validation rate of 90%.

Participants reported being diagnosed with psoriasis between the ages of 1–69 years (Mean = 47, standard deviation = 15) (Table 1). 30% reported being diagnosed by non-dermatologists. 79% reported having mild psoriasis, 17% moderate and 4% severe.

Table 1.

Characteristics of women with psoriasis in Nurses’ Health Study II who completed the PST-2 questionnaire (n=1243).

Characteristic	Mean (SD) or Frequency (%)
Age at diagnosis of psoriasis (yrs)	47 (15)
Medical provider who made the diagnosis:
Dermatologist	70
Non-dermatologist	30
Severity of psoriasis based on the BSA* reported by subjects:
Mild (<3% BSA)	79
Moderate (3–10% BSA)	17
Severe (>10 % BSA)	4
Phenotypes of psoriasis**:
Scalp	49
Plaque	41
Inverse	27
Nail	22
Palmoplantar	15
Treatment modalities:
Only topical	54
Only UV	1
Only systemic	5
Topical and UV	6
Topical and systemic	7
UV and systemic	1
Topical, UV and systemic	3
No treatment	23
Years of psoriasis diagnosis:
Before 2003	36
2003–2007	17
2008–2012	32
2013–2016	15

^*BSA, body surface area

^**Some individuals reported more than one phenotype of psoriasis.

Among individuals with mild psoriasis, 33% were diagnosed by non-dermatologists. Among individuals with moderate-to-severe psoriasis, 13% were diagnosed by non-dermatologists.

Different phenotypes of psoriasis reported by participants in our study included scalp (49%), plaque lesions (41%), inverse (27%), nail disease (22%) and palmoplantar involvement (15%).

In individuals diagnosed by a dermatologist, 58% used only topical treatment (Figure 1A), 24% used systemic therapy and/ or phototherapy and 18% reported not using any of these treatments. In individuals diagnosed by a non-dermatologist provider, 45% used only topical treatment (Figure 1B), 19% used systemic therapy and/or phototherapy and 36% reported not using any of these treatments.

Figure. 1.

Treatment patterns of psoriasis by medical provider in Nurses’ Health Study II A. diagnosed by a dermatologist B. diagnosed by a non-dermatologist provider.

In individuals with mild psoriasis, 58% used only topical treatment (Figure 2A), 16% used systemic therapy and/or phototherapy and 26% reported not using any of these treatments. In individuals with moderate-to-severe psoriasis, 42% used only topical treatment (Figure 2B), 47% used systemic therapy and/or phototherapy, and 11% reported not using any of these treatments. 7% of individuals with mild psoriasis and 13% of individuals with moderate-to severe psoriasis underwent more than 150 sessions of UV therapy.

Figure. 2.

Treatment patterns of psoriasis by severity in Nurses’ Health Study II A. mild psoriasis, B. moderate-to-severe psoriasis.

Figure 3 demonstrates the distribution of different types of systemic treatment used in our cohort. As expected, a substantially higher percentage of people with moderate-to-severe psoriasis received targeted and/or traditional systemic therapy compared to those with mild psoriasis. Methotrexate and adalimumab were the most commonly used traditional and targeted medications, respectively.

Figure. 3.

Systemic treatment of psoriasis in Nurses’ Health Study II A. mild psoriasis B. moderate-to-severe psoriasis

Discussion

In this study of US female nurses with psoriasis, 21%of women reported to have moderate-to severe psoriasis. There are different measurement tools to assess the severity of psoriasis including psoriasis area and severity index (PASI), BSA, and physician global assessment (PGA). A study compared PASI, PGA and BSA, and showed that the PGA has the highest interrater reliability, whereas the BSA has the highest intra-rater reliability.²⁰ The PASI showed intermediate values in terms of inter- and intra-rater reliability. However, none of the 3 assessment instruments showed a significant advantage over the other.²⁰ In our study, severity was reported by participants based only on the BSA affected by psoriasis. BSA has been previously reported as the most important factor related to reduction in QoL associated with psoriasis.^21,22

Previously Stern et al. in a population-based cross-sectional study in the US and by using a self-administered questionnaire showed that 83% of participants reported mild, 11% moderate and 3% reported severe psoriasis.⁴ In a clinic-based study conducted by Fleischer et al. in the US, 41% of the participants had mild, 50% moderate and 9% had severe psoriasis.²³ Similar to other population-based studies using a self-reported method of extent of disease, our population included a smaller proportion of patients with extensive psoriasis and the vast majority of people with psoriasis reported to have skin lesions covering less than 3% BSA.

Our results on the body sites involved are consistent with a recent study which reported the prevalence of different phenotypes of psoriasis using the largest US dataset.⁷ They reported scalp involvement in 45–56%, inverse psoriasis in 21–30%, nail disease in 23–27% and palmoplantar disease in 12–16% of psoriasis patients. In fact, NHS II was part of the population in their report. Compared to our study the prevalence of plaque lesion and scalp disease was higher in their report. In contrast to our study, they reported a higher prevalence for plaque psoriasis compared to scalp disease. Prevalence of nail disease, inverse psoriasis and palmoplantar involvement was almost the same as our results.⁷ Treatment of psoriasis in these areas can be even more challenging owing that usually people with these phenotypes of psoriasis are either excluded from pharmaceutical clinical trials or assessment of these areas are not point of interest in these trials. Therefore, there is a lack of evidence regarding efficacy of different treatment modalities for these specific phenotypes of psoriasis. Also, patients with psoriasis in these areas may not receive effective treatment because (a) physicians may not appreciate the full burden of disease in these areas and/ or (b) patients may be reluctant to discuss disease affecting these areas unless specifically asked.¹³ Involvement of these body sites is often associated with a profound negative impact on a patient’s QoL, because they can cause pain, embarrassment, sexual dysfunction and impairment in daily life activities.¹³

30% of participants in our study were never diagnosed by a dermatologist, although this number was lower in participants with moderate-to severe psoriasis. Financial concerns, insurance coverage for specialist visits and the referral process from primary care providers may all be barriers to specialist care.

In individuals with moderate-to severe psoriasis 53% of patients received only topical therapy or no treatment at all. Based on American Academy of Dermatology (AAD) consensus statements on psoriasis therapies, these individuals often need more aggressive therapies including systemic medication and phototherapy.²⁴ So, it seems that many people with more severe psoriasis are undertreated. There are also several previous reports that show individuals with moderate-to-severe psoriasis are untreated or undertreated.^{4,13,18,25,26} In contrast, 16% of individuals with mild psoriasis received systemic therapy and/or phototherapy. This could be due to that some of these patients might have had psoriatic arthritis, other more resistant phenotypes of psoriasis or no adequate response to previous topical agents which warranted more aggressive treatment by systemic medication. The AAD consensus statements on psoriasis therapies indicated that patients with psoriatic arthritis may have limited skin disease but require more aggressive systemic therapies. Also, people with mild disease, based on limited BSA involvement, may still warrant phototherapy or systemic therapy, if not responsive to topicals or if there is disruption of daily activities and/or employment.²⁴

Our study has important limitations to consider. Firstly, the severity of psoriasis was determined only based on self-reported BSA affected by psoriasis; other important factors such as the thickness and scaling of lesions, the presence of associated psoriatic arthritis and the impact of psoriasis on QoL were not evaluated. Secondly, our study population is from a cohort of female nurses who are mostly white, limiting the generalizability of this study to all patients including both genders with different ethnicities, education levels, income and insurance coverage, which could affect the treatment pattern of psoriasis. Finally, recall bias could be another limitation of our study.

In conclusion, the majority of women in NHS II with psoriasis have mild disease and are managed with topical therapy. Many of them reported non-plaque phenotypes such as scalp, intertriginous, nail and palmoplantar involvement. A large proportion of people with moderate-to-severe disease received only topical therapy or no treatment at all. Many women with psoriasis are diagnosed by non-dermatologist providers, suggesting that engagement of non-dermatologists in educational initiatives to improve psoriasis management is warranted.

Abbreviations

NHS II

Nurses’ Health Study II

PST

psoriasis screening tool

PST-2

psoriasis screening tool-2

QoL

quality of life

BSA

body surface area

UV

ultraviolet

AAD

American academy of dermatology