During the study period, 272 PsA (male 141, female 131) patients satisfying the inclusion criteria were enrolled.

There were not statistically significant differences, in terms of clinical and demographic features, between patients from the two centers (data not shown).

Table 1 shows the main clinical characteristics of the total enrolled patients divided by sex. Generally, in terms of differences, BMI and BSA were higher in males, while PtGA, PtPnV, TJC, SJC, DAPSA, HAQ-DI, and PsAID-12 were higher in females. The latter had a higher prevalence of fibromyalgia (F 19.2 vs. M 2.2%, p < 0.001). Moreover, MDA and an acceptable symptom state (PASS yes) were less likely present in females than males.

In terms of similarities, age, disease duration, psoriasis onset age (EOP and LOP), PsA patterns, dactylitis, LEI, CRP, PGA, and the current therapy were not different between the two sexes. However, even if there were no statistically significant differences, a higher percentage of females were on csDMARDs and tumor necrosis factor inhibitors (TNFi), while a higher number of male patients were on anti-IL-12/23 treatment.

Mean DAPSA was statistically significant higher in females. However, DAPSA is good for assessing peripheral arthritis, not other manifestations of PsA, and may not capture all the elements influencing disease reporting. Of note, when analyzing each DAPSA component, TJC, SJC, PtGA, and PtPnV were higher in females, despite CRP values were not different between the two groups, as previously mentioned.

Females, compared with males, reported higher mean pain [5 (± 2.78) vs. 4 (± 2.60), p = 0.003] and worst mean PtGA: [5.01 (± 2.51) vs. 3.99 ± 2.45, p < 0.001].

These data are also in keeping with worst function assessed by HAQ-DI, worst impact of the disease assessed by PsAID-12, and less presence of PASS yes ([69.5% in males and 47% in females, respectively, χ2 (1, n = 245) = 11.88, p < 0.001].

Finally, MDA, considered in the total population was present in 83/239 (34.7%), but when calculated by dividing the two sexes, this percentage was significantly different: 44% in males vs. 24.6% in females, [χ2 (1, n = 239) = 9.10, p = 0.003]. Moreover, going deeper into MDA domains, females, compared with males, less likely had PtPnV ≤ 1.5, HAQ-DI ≤ 0.5 and TJC ≤ 1; on the other hand, males less likely had a BSA ≤ 3 when compared with females (Table 2, Fig. 1).

Sex differences in the achievement of MDA domains

Mean (SD) BSA was higher in males: 2.16 (± 3.74) vs. 1.22 (± 2.26), p = 0.015. A possible role of psoriasis, measured as BSA, on the burden of the disease was analyzed in the two sexes. We found that PtGA was different in males and females with regard to BSA; in fact, when comparing median PtGA between males and females with BSA > 0, a statistically significant difference was found (p = 0.038), with females showing higher values of PtGA; therefore, when psoriasis was present, a sex difference in PtGA was observed. On the other hand, when comparing PtGA in females with BSA = 0 to males with BSA = 0, there was a trend to be worse in females, even if it was not statistically significant (median PtGA (IQR): 4 (3–6) and 3 (2–5), respectively). In the same way, when comparing PtGA in females with BSA = 0 to female with BSA > 0, there was a trend to be worse in females with BSA > 0, even if it was not statistically significant (median PtGA (IQR): 4 (3–6) and 6 (4–8), respectively). Moreover, males with BSA > 0 or BSA = 0 were also better than females with BSA > 0, and it was statistically significant in both cases (Fig. 2).

Comparison of PtGA based on sex and BSA. Patients were stratified in four groups based on sex and BSA category. Females with BSA = 0; females with BSA > 0; males with BSA = 0; males with BSA > 0. PtGA was compared among these groups using Kruskal–Wallis test. The table shows the p values for each comparison

These results could have been influenced by the sample size; however, these trends could be of some importance to distinguish the role of skin involvement in PtGA between males and females.

Finally, to evaluate any association between BSA and PtGA, independently by others confounding factors, we performed two multiple linear regression analysis, for males and females, respectively.

In male patients, the association between BSA > 0 and PtGA was not statistically significant (p = 0.169), when adjusted for other confounding factors (Table 3, model 1) (adjuster R2:0.21).

In female patients, the association between BSA > 0 and PtGA was not statistically significant, even if with a trend of significance (p = 0.074) was found (Table 3, model 2). Therefore, it could mean that when psoriasis is present in females, the mean value of PtGA tends to increase by 0.75, independently of articular involvement (TJC and SJC) and fibromyalgia (adjuster R2:0.25).