Clinical features of Chinese psoriatic patients for early referral of arthritis using psoriasis epidemiology screening tool: A cross-sectional analysis from the registry database of Chinese Psoriasis Standardized Diagnosis and Treatment Center

To the Editor: Psoriatic arthritis (PsA) is a type of arthritic condition that occurs in patients with psoriasis. Early identification of patients at risk and the knowledge of risk factors is crucial for dermatologists. The Chinese Psoriasis Standardized Diagnosis and Treatment Center (CPSDTC) registry database is a prospective, multicenter cohort study launched by the Peking University First Hospital in July 2020 to gather clinical information on Chinese patients with psoriasis. Our study aimed to report the clinical features of Chinese psoriatic patients using the Psoriasis Epidemiology Screening Tool (PEST) for the early referral of arthritis.

We conducted a study on 5860 adult patients registered in the CPSDTC database using the PEST scores to identify patients with a higher risk of developing PsA. Patients with a PEST score ≥3 were compared with those having a PEST score <3 to analyze demographic and clinical characteristics. These patients were recruited from over 200 academic practice sites across China, and ethical approval was obtained from the Peking University First Hospital Ethics Board (No. 2020-255) and Wuhan No.1 Hospital Ethics Committee (No. 2020-20). Each patient signed an written informed consent form. The PEST comprises of five simple yes/no questions, with each response assigned a value of one point. A PEST score of ≥3 indicates a high risk of PsA, and these patients may require referral to rheumatologists for diagnosis and treatment.

Descriptive statistics of Table 1 were performed with frequencies for categorical variables and means and standard deviation (SD) for quantitative variables. Comparisons of descriptive data between PEST groups (PEST score <3 and PEST score ≥3) were performed using two-sample t-tests or chi-squared tests or Fisher's exact tests. A P value of <0.05 was considered statistically significant. SPSS 23.0 (IBM Corp, Armonk, USA) was used for all statistical analyses.

Table 1.

Demographic and clinical characteristics of patients with psoriasis stratified by PEST score.

Characteristics	PEST <3 (n = 5392)	PEST ≥3 (n = 468)	P values
Male	3508 (65.1)	332 (70.9)	0.010
Age (years)	42.8 ± 15.1	44.8 ± 13.6	0.002
Bodyweight (kg)	68.5 ± 13.0	70.6 ± 13.2	0.001
BMI (kg/m2)	24.0 ± 3.7	24.7 ± 3.7	<0.001
Normal/underweight <25	3510 (65.1)	258 (55.1)	<0.001
Overweight 25–29	1584 (29.4)	172 (36.8)	<0.001
Obese ≥30	298 (5.5)	38 (8.1)	0.021
Work status
Employed	3379 (62.7)	289 (61.8)	0.695
Unemployed	471 (8.7)	55 (11.8)	0.029
Students	395 (7.3)	17 (3.6)	0.003
Retirement	831 (15.4)	78 (16.7)	0.472
Current smoking status	1436 (26.6)	139 (29.7)	0.152
Family history of psoriasis	732/5225 (14.0)	96/452 (21.2)	<0.001
Psoriasis duration (years)	9.5 ± 9.8	12.4 ± 10.6	<0.001
	(n = 5215)	(n = 452)
Nail involvement	194 (3.6)	63 (13.5)	<0.001
Scalp involvement	3210 (59.5)	325 (69.4)	<0.001
Palmoplantar involvement	857 (15.9)	143 (30.6)	<0.001
External genitalia involvement	585 (10.8)	110 (23.5)	<0.001
Plaque type	4335 (80.4)	348 (74.4)	0.002
Pustular type	144 (2.6)	16 (3.4)	0.341
Erythrodermic type	156 (2.9)	24 (5.1)	0.007
PASI	10.3 ± 10.4	12.9 ± 12.3	<0.001
	(n = 4976)	(n = 430)
BSA	18.3 ± 21.4	23.7 ± 25.5	<0.001
IGA score
1	505/4982 (10.1)	34/432 (7.9)	0.131
2	1724/4982 (34.6)	96/432 (22.2)	<0.001
3 or 4	2753/4982 (55.3)	302/432 (69.9)	<0.001
DLQI	8.2 ± 6.6	12.6 ± 7.6	<0.001
Comorbidities	685/5106 (13.4)	117/447 (26.2)	<0.001
Cardiovascular disease	339 (6.6)	52 (11.6)
Diabetes	151 (3.0)	20 (4.5)
Respiratory disease	29 (0.6)	6 (1.3)
Liver and gastric disease	102 (2.0)	19 (4.3)
Rheumatology disease	20 (0.4)	13 (2.9)
Malignance	12 (0.2)	1 (0.2)
Allergic disease	21 (0.4)	4 (0.9)
Renal disease	11 (0.2)	2 (0.4)
Biologic therapy history	621/5072 (12.2)	56/445 (12.6)	0.834
Systemic therapy history	2483/5077 (48.9)	227/445 (51.0)	0.395

Data are presented as n (%), n/N (%) or mean ± standard deviation. BMI: Body mass index; BSA: Body surface area; DLQI: Dermatology Life Quality Index; IGA: Investigator's global assessment; PASI: Psoriasis area and severity index; PEST: Psoriatic arthritis screening tool; Biologic therapy history included adalimumab, etanercept, infliximab, ixekizumab, secukinumab, ustekinumab, and other investigative biologics.

Up to September 3rd, 2021, a total of 158 patients (2.7%) among 5860 patients had been diagnosed with PsA at the enrollment, in which 43 (0.73%) had PEST score <3 and 115 (1.97%) had PEST score ≥3. Totally, 468 (8.0%) had a PEST score ≥3. The distribution of PEST scores and five questions in PEST questionnaire in PEST ≥3 group can be seen in Supplementary Figure 1, http://links.lww.com/CM9/B607.

Demographics and treatment history are shown in Table 1, patients with a PEST score ≥3 were significantly older than patients with a PEST score <3 (mean [SD], 44.8 [13.6] years vs. 42.8 [15.1] years; P = 0.002). They were also more likely to be male (70.9% vs. 65.1%; P = 0.010) and have a higher body weight (mean [SD], 70.6 [13.2] kg vs. 68.5 [13.0] kg; P = 0.001). The ratios of overweight and obese were both higher (36.8% [172/468] vs. 29.4% [1584/5392]; 8.1% [38/468] vs. 5.5% [298/5392], respectively; P <0.001), and were more likely to be unemployed (11.8% [55/468] vs. 8.7% [471/5392]; P = 0.029). No differences in the use of biological and systemic treatments for psoriasis and smoking status were observed between groups.

Patients with a PEST score ≥3 were found to have a higher prevalence of comorbidities such as cardiovascular disease, diabetes, intestinal, and respiratory diseases compared to those with a PEST score <3 (26.2% vs. 13.4%; P <0.001). They were also more likely to have a family history of psoriasis (21.2% vs. 14.0%; P <0.001).

Moreover, patients with a PEST score ≥3 had a longer duration of psoriasis (mean [SD], 12.4 [10.6] vs. 9.5 [9.8] years; P <0.001) and exhibited more common nail psoriasis (13.5% vs. 3.6%; P <0.001), scalp psoriasis (69.4% vs. 59.5%; P <0.001), palmoplantar (30.6% vs. 15.9%; P <0.001), and external genitalia involvement (23.5% vs. 10.8%; P <0.001) compared to those with a PEST score <3 [Table 1]. Notably, patients with PEST score ≥3 had a higher proportion of erythrodermic psoriasis than those with PEST score <3.

Additionally, patients with a PEST score ≥3 had greater psoriasis severity, as measured by categorical investigator's global assessment (IGA) score (3 or 4, 69.9% vs. 55.3%, P <0.001), percent affected BSA (mean% [SD%], 23.7 [25.5] vs. 18.3 [21.4], P <0.001), and mean psoriasis area and severity index (PASI) score (mean [SD], 12.9 [12.3] vs. 10.3 [10.4], P <0.001). Patient-reported outcome measures revealed that patients with a PEST score ≥3 also had significantly worse Dermatology Life Quality Index (DLQI) scores (12.6 [7.6] vs. 8.2 [6.6]; P <0.001) [Table 1].

This research discovered that 8% of psoriasis patients had a PEST score of ≥3, while only 2.7% had been diagnosed with PsA at the beginning of the study. Compared with 5.4% of Chinese psoriasis patients reported to be concurrent with PsA,^[1] this indicates a significant unfulfilled requirement for referring such patients to rheumatologists.

The PEST tool was more effective than other methods in identifying the risk of PsA, with a sensitivity of 0.92 and specificity of 0.78. The findings are supported by a similar Chinese study demonstrating that about 7.8% of psoriasis patients require referral to rheumatologists using the PEST.^[2]

Middle-aged men with a higher body mass index, longer disease duration, family history of psoriasis, and worse skin condition (based on PASI, IGA, and BSA scores) were identified as predictors of PsA development. While no significant gender difference was found in PsA, the spinal involvement is more frequent in men.^[3]

Compared with psoriasis alone, PsA was associated with more comorbid conditions and higher cardiovascular risk.^[3] In our PEST score ≥3 cohort, the most prevalent comorbidities were cardiovascular disease, followed by diabetes.

Notably, the specific body sites involvements and the uncommon subtypes of psoriasis were also significantly associated with a higher risk of PsA, such as scalp lesions, nail dystrophy, palmoplantar, and intergluteal/perianal lesions. And the pustular and erythrodermic subtype is significantly positive associated with PsA.

By analyzing the data of 5860 adult patients, we found that using PEST screening, 8% of psoriasis patients were identified as having a higher risk of developing PsA, lower than the counterpart in the United States.^[4] Patients with a PEST score ≥3 were more likely to be older, male, overweight, unemployed, having comorbidities, longer duration of psoriasis, worse skin severity, and specific body sites involvement. These findings underline the importance of early referral of these patients to rheumatologists.

Our research has some limitations, including potential bias due to individuals already being treated or lack of laboratory tests, imaging examinations, and follow-up outcomes. Nonetheless, our findings provide valuable insights into the risk factors of psoriasis patients with PEST scores of ≥3 registered in China. We should be aware of the possibility that many of these patients could have undiagnosed PsA and timely referral to rheumatologists are needed to avoid the delay diagnosis.

Acknowledgments

We would like to thank all the patients in registry database of Chinese psoriasis standardized diagnosis and treatment center.

Funding

This work was supported by grants from the National Natural Science Foundation of China (No. 81974474) and Natural Science Foundation of HuBei Province (No. 2020CFB503).

Conflicts of interest

None.

Supplementary Material

cm9-136-1999-s001.docx ^{(96.9KB, docx)}