RESUMO
BACKGROUND: Central sensitization (CS) is a condition characterized by a disproportionate response to pain stimuli. We sought to investigate the prevalence of CS in patients with inflammatory arthritides and its association with measures of disease activity and functional disability. METHODS: We conducted an observational retrospective study in psoriatic arthritis (PsA) and rheumatoid arthritis (RA) patients. We administered to all the subjects in the study the CS inventory (CSI), a questionnaire that has been used for the diagnosis of CS. Demographic and clinical characteristics were collected as well as measures or disease activity [i.e. Simple Disease Activity Index, Disease Activity Score in PsA (DAPSA)] and functional disability [Health Assessment Questionnaire Disability Index (HAQ-DI)]. Patients with fibromyalgia were excluded from the analyses. The primary outcome measure was the presence of functional disability as assessed by HAQ-DI >1. RESULTS: We enrolled 150 patients with inflammatory arthritides (78 PsA and 72 RA). Prevalence of CS was observed in 35.3% of the overall sample (29% in RA, 42.9% in PsA). Binary logistic regressions showed a strong, independent and linear association between functional disability and CS in both PsA and RA patients. The strength of this association was greater in PsA than in RA. CONCLUSION: CS is an important determinant of functional disability in patients with chronic inflammatory arthritides. PsA appeared to be more vulnerable to CS. In addition, in the presence of CS, DAPSA did not adequately capture the occurrence of functional disability. Therefore, special attention should be paid to PsA patients, in whom the concomitant diagnosis of CS should be routinely ruled out.
RESUMO
Psoriatic Arthritis (PsA) is characterized by bone erosive damage often associated with exuberant bone formation especially in enthesial sites. Dkk-1 and sclerostin are the main inhibitors of the WNT/ß-catenin signaling pathway and play a key role in the regulation of both bone formation and resorption. We performed this study in order to compare the serum levels of the WNT-pathway regulators along with bone turnover markers (BTM) and parathyroid hormone (PTH) between three different groups: one group of female patients affected by PsA, one group of female patients affected by rheumatoid arthritis (RA), and healthy female controls (HC). This is a cross-sectional study including 33 patients with PsA classified with the CASPAR criteria, 35 HC, and 28 patients with RA classified with the ACR/EULAR 2010 criteria. Intact N-propeptide of type I collagen (PINP), C-terminal telopeptide of type I collagen (CTX-I), Dickkopf-related-protein 1 (Dkk-1), sclerostin, PTH, and 25OH-vitamin D serum levels were dosed. The PsA group showed significantly lower Dkk-1 levels when compared to the HC and RA groups. Dkk-1 in the RA group was significantly higher than HC. A similar trend was documented for PTH. In the PsA group, CTX-I was found to be lower than in both the RA and HC groups. This study demonstrated for the first time that Dkk-1 levels in PsA are lower than HC, in contrast with RA, in which they are increased. These results might contribute to explain the different bone involvement of the two different diseases.