Introduction

Psoriasis is a chronic immune-mediated inflammatory disease affecting the skin and is frequently associated with joint disorders (psoriatic arthritis) [1–3]. Furthermore, the psoriatic disease is leading to numerous comorbidities including metabolic syndrome, depression and cardiovascular diseases[1,2]. Affecting visible areas such as face, hands and nails, psoriasis may create stigmatization and result in a heavy emotional burden and extensive psychosocial effects affecting personal and social life as well as interpersonal relationships [4]. Furthermore, skin lesions often are accompanied by agonizing pruritus. Joint involvement frequently is associated with chronic pain, myalgia and movement restrictions. This additionally can lead to the reduction of psychological conditions and have a negative impact on well-being [4] Depending on the severity of disease and the affection of life quality, treatment is initiated [5–8]. Dermatology Life Quality Index (DLQI) is a questionnaire with 10 items, covering personal discomfort (itch, sore, pain or stinging) and perception (embarrassment, self-consciousness), but also personal interactions (partner, family, friends). Furthermore, the impact of the skin disease on mandatory duties (work/school, shopping, housekeeping, gardening), and social/leisure activities as well as sports are queried. Questions of impairment can be answered with very much (scored 3), a lot (scored 2), a little (scored 1), not at all (scored 0) or not relevant (scored 0). The final DLQI is calculated by summing the score of each question, the higher the score, the more quality of life is impaired. At the beginning of 2020, the human-to-human transmission of COVID-19 forced governments worldwide to implement restrictions on individual mobility and face-to-face interaction. These restrictive measures ranged from working-from-home to ‘shelter-in-place’, closure of schools and non-essential businesses. In Germany, there were massive restrictions in social life to keep people safe. To date, data on the effects of social restrictions under lockdown regulations during the COVID-19 pandemic on life quality and social life of psoriasis patients are lacking. Thus, the aim of this retrospective single-center cohort study was to longitudinal compare patient-reported outcomes before the COVID-19 era and under harsh measures initiated to contain the spread of the virus.

Materials and methods

The current retrospective cohort study included selected patients diagnosed with moderate to severe psoriasis treated with biologics between January 1^st_, 2020, and March 31^th, 2021 at the Comprehensive Center for Inflammation Medicine, University of Lübeck, Lübeck, Germany. The study was approved by the institutional ethical committee in accordance with the Declaration of Helsinki. All patients have given written informed consent.

The electronic medical records of eligible patients were systematically reviewed. Psoriasis was diagnosed based on compatible clinical manifestation +/- confirmatory histology. Joint involvement was confirmed by clinical examination and radiologic findings at baseline. The following variables were retrieved: PASI⁵ and DLQI⁶ before onset of the pandemic (January 2020) and under social life restrictions due to due lockdown (January 2021) as well as the utilized systemic therapeutic modalities. DLQI questionnaires were handed out to the patients at their regular visits at the Comprehensive Center for Inflammation Medicine, University of Lübeck, Lübeck, Germany.

Results and discussion

The current study included 103 patients with moderate to severe psoriasis with or w/o joint involvement, of whom 29 (28.2%) were females and 74 (71.8%) were males. The median (range) age of study participants was 54 (18–85) years. Psoriasis was the most frequently encountered manifestation (n = 84; 81.6%), whereas PsA was present in 19 (18.4%) patients (Table 1). The mean (SD) PASI score pre-COVID was 3.6 (5.6). Under lockdown restriction, mean (SD) PASI score was calculated 1.6 (2.31). Of note, all patients were under ongoing continuous biologic treatment at the time point of study inclusion, this may reflect the low PASI at baseline and only slight improvement over time. The majority of study participants (n = 39; 37.9%) underwent treatment with anti-IL-23. Thirty (29.1%) patients were managed by anti-IL-17A, 25 (24.3%) patients were under anti-IL-12/23 and 9 (8.7%) patients were treated with anti-TNFα as delineated in Table 1.

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Table 1. Demographic and clinical characteristics.

https://doi.org/10.1371/journal.pone.0275293.t001

The longitudinal quality of life analysis of this cohort of psoriasis patients showed that the mean (SD) and median (range) DLQI scores shortly before the COVID-19 pandemic were 5.6 (7.38) and 2.0 (0–30), respectively. Whereas under lockdown restriction, a mean (SD) 2.7 (5.11) and a median (range) 1.0 (0–25) DLQI score was calculated (Table 1). Comparing DLQI scores shortly before the onset of the COVID-10 pandemic and under harsh lockdown restrictions demonstrated that life quality of most patients with psoriasis, contrary to what was expected, improved. Analyzing DLQI questionnaires on social activities during pandemic showed that questions concerning social activities like work/school, shopping, and social/leisure activities as well as and self-perception and personal interactions were answered with “not relevant” or “not at all” (Table 2). As this item is scored 0, this may lead to an artificial improvement of life quality measurements. This paradoxical improvement of DLQI during the COVID-19 pandemic suggests that DLQI should be modified when social life is restricted, as these scores evaluated under restrictions (with a lot “not relevant” responses) do not reflect the true extent of negative impact on life quality. This is in line with recently published observation which showed that DLQI improved due to “not relevant” responses [9]. Moreover, it was shown that the “not relevant” ticked box can have an impact on the treatment decisions [10]. This data underlines, the importance of adjusted validation of patient-reported outcome scores in pandemic or patient-individual situations [9–12].

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Table 2. Dermatology Life Quality Index measurement of social activities.

https://doi.org/10.1371/journal.pone.0275293.t002

Limitations of the study include the relatively small number of patients and its retrospective nature. This may have resulted in some degree of selection bias, given that the patients were attending a tertiary referral center. Psoriasis treatment had been initiated prior to inclusion to this analysis.

Conclusions

This retrospective cohort study revealed that DLQI paradoxically improved under social restrictions, increasing the awareness to life situation adjusted validation of DLQI scores. Our findings underscore the importance of individual evaluation of patient-reported outcomes in order to reflect the burden of the underlying chronic skin disease and not the impact of general life circumstances. Furthermore this data underlines the effects of “not relevant” answer on the validity of DLQI score.

Supporting information