Diagnosis and underdiagnosis of comorbidities in psoriasis patients - need for a multidisciplinary approach*

BACKGROUND Psoriasis is an immune-mediated disease that manifests predominantly in the skin, although systemic involvement may also occur. Although associated comorbidities have long been recognized and despite several studies indicating psoriasis as an independent risk factor for cardiovascular events, little has been done in general medical practice regardind screening. In the United States, less than 50% of clinicians are aware of these recommendations. OBJECTIVE To identify the prevalence of these comorbidities in 296 patients followed up at a university dermatology clinic. METHODS Systematically investigated comorbidity frequencies were compared with general practitioners' registry frequencies. Clinical features correlated with comorbidities were also investigated. RESULTS High prevalences of systematically investigated comorbidities such as hypertension (30%) and dyslipidemia (26.5%) were documented. Conversely, data from general practitioners' records showed that 33% of dyslipidemia cases were undiagnosed and indicated possible underdiagnosis of some comorbidities. Furthermore, an association was found between: the number of comorbidities and psoriasis duration, age and high body mass index an association was found between the number of comorbidities and psoriasis duration, age, high body mass index, waist circumference or waist-to-hip ratio. (p<0.05). CONCLUSION Disease duration, age and high body mass index, waist circumference or waist-to-hip ratio are possible criteria for choosing which patients should be screened for comorbidities. Underdiagnosis of comorbidities by general practitioners highlights the need for a multidisciplinary approach in psoriasis management.


INTRODUCTION
Since 1818, when an association between psoriasis and joint disorders (psoriatic arthritis) was reported, various other comorbidities have been described, including systemic arterial hypertension (SAH), diabetes mellitus (DM), and cardiovascular disease. 1,2 Other comorbidities, such as celiac disease and erectile dysfunction, have been described more recently. [3][4][5] The clinical manifestations of comorbidities generally appear years after the onset of psoriasis and are more common in severe cases. [6][7][8] Furthermore, a high frequency of smoking has been noted in psoriasis patients. 9 Systematic reviews have consistently demonstrated an increased cardiovascular risk and the need for appropriate prevention measures. [10][11][12] Alarming rates of obesity and overweight were described in Brazilian psoriasis patients. Moreover, waist circumference and waist-to-hip ratio (WHR) showed a better correlation with the psoriasis severity. 13 Although associated comorbidities have long been recognized, there may be a theory-practice dissociation in psoriasis care by dermatologists and there remains an unanswered question over how comorbidities should be screened and who should undertake this task.
This study aimed to determine the prevalences of SAH, DM, dyslipidemia (DLP) and smoking consumption in psoriasis patients (by screening every patient actively), and ascertain the prevalence of other previously diagnosed comorbidities (data from general practitioners' (GPs) registries). In addition, the features bearing a high correlation with comorbidities were investigated.

METHODS
The data analyzed in the present cross-sectional study were obtained from a sample of 296 psoriasis patients followed up at the

Specific procedures:
The psoriasis area severity index (PASI) was used to assess psoriasis severity and a score of > 10 was considered moderate-to-severe psoriasis. 14  Smoking was evaluated in pack-years, both for current and former smokers. Current smokers were also stratified in accordance to the mean number of cigarettes smoked/day: < 10 cigarettes/day, 10-20 cigarettes/day or > 20 cigarettes/day. 16 Other comorbidities were obtained by examining the patients' GP medical records. Criteria and investigations used for their detection are not thoroughly described here (retrospective data).

Data analysis
Statistical analysis was conducted using the SPSS version 11.5 for Windows. The continuous variables were described as means ± standard deviation of the mean, and the categorical variables as proportions.  reported, but neither gender nor psoriasis severity were associated with the occurrence of comorbidities. 18,19 In contrast, however, previous studies have demonstrated that the greater the psoriasis severity, the stronger the association with comorbidities and, consequently, the higher the patient's cardiovascular risk. [20][21][22] During the follow-up, 19 new DLP cases and 2 new SAH cases were identified, suggesting insufficient screening by GPs. The frequencies found for SAH and DM in this outpatient sample were similar to those found in other studies. 11,17 DM incidence in patients with psoriasis correlates positively with BMI, the duration of the disease and/or the use of systemic therapy. 23 DLP has consistently been associated with psoriasis even after adjustment for other known, confounding factors. [24][25][26] In this study, DLP active screening increased diagnosis in 33% (19/57) of patients. Despite the impact of retinoids, cyclosporine and anti-TNF-α agents on lipid levels, the authors believe that the majority of undiagnosed cases is due to increased medical surveillance. [27][28][29] Epidemiological data from the Brazilian population show the following frequencies: SAH (33.7%); DM (8.0%); smoking (25.2%) and DLP (24.2%). [30][31][32] Notably, the frequencies for several of the comorbidities evaluated were lower than the rates reported in the literature. For example, the rate of depression -also associated with an increased risk of cardiovascular disease -was almost ten times less than the expected. 33 This underdiagnosis merits the utmost attention, since in up to 10% of psoriasis cases, it is severe enough to induce suicidal ideation. 34 A similar level of underdiagnosis (1.7%) was found for non-alcoholic fatty liver disease, much lower than the level reported in the literature. [27][28][29] Despite the publication of several population-based studies indicating psoriasis as an independent risk factor for cardiovascular events, motivating the adoption of screening for additional risk factors, it is known that these guidelines are largely ignored. 35,36 In the United States, less than 50% of clinicians are aware of these recommendations. 37   chronic nicotine abuse on psoriasis severity. 39,40 This research has some limitations, including sample size and impossibility to establish causal relationships between correlated variables.

CONCLUSION
This study shows that, despite being known for decades, some comorbidities are underdiagnosed in psoriasis patients. This finding serves as an alert to clinicians, dermatologists and healthcare authorities, emphasizing the need for multidisciplinary man-agement and active screening, which would reduce the impact of these comorbidity associations on patients' survival, quality of life and mortality, reinforcing the need for changes in healthcare in concordance with growing evidence of theory-practice dissociation in psoriasis management.
The data from this and a previously published study 13 enhance our understanding of increases in comorbidities according to age, time of psoriasis, BMI, WHR and waist circumference, which are possible criteria for determining which patients should be screened for comorbidities.q