Objectives Psoriatic arthritis (PsA) is a chronic inflammatory joint disease that develops in 6%–48% of the patients with Psoriasis and linked to other health concerns such as obesity, type II diabetes, dyslipidemia, hypertension and cardiovascular diseases. This association can be attributed to the chronic inflammatory process but also to shared genetic susceptibility among these diseases. The role of these metabolic disturbances in the pathogenesis, severity and progression of PsA remains unclear. Datasets about comorbidities in patients with PsA remain scarce. We therefore analysed comorbidities in PsA patients and compared them with other types of SpA.
Methods Study participants were taken from the Spondyloarthritis Registry at the Division of Rheumatology, University Hospitals Leuven which includes 262 PsA and 256 other SpA patients, in clinical follow-up and contains all demographic, medical and laboratory information. The patients were grouped depending on their diagnosis and analysed on the basis of age, gender, education, workstatus, disease duration, treatment, type and number of comorbidities. The data were analysed using chi-square test, t-test, Fisher exact test and logistic regression model with correction for confounding factors (age, gender, disease duration, medication).
Results Out of 518 patients (62.74% males, 37.25% females), 53.66% were found to have comorbidities. On one hand PsA patients were significantly older than other SpA patients (mean = 58.8 years vs. 44.9 years) while on the other hand SpA patients had significantly longer disease duration when compared to PsA patients (14.10 years vs. 7.12 years) (p < 0.05). The PsA group was found to have more comborbidities as compared to SpA (p < 0.05) and this difference remained significant using logistic regression model (OR: 1.71, p = 0.01). The cardiovascular and metabolic comorbidities were significantly higher in the PsA group as compared to SpA (p < 0.01). Coronary artery disease, hypertention, hyperlipidemia, malignancy and metabolic syndrome showed a marked difference between the 2 groups (p < 0.05). All these differences among the two groups remained significant even using logistic regression model (p < 0.001). We could not find any relation of work status, medication and education with prevalence of comorbidites.
Conclusion There is a significant increase in cardiovascular and metabolic comorbidities including malignancy in patients with PsA as compared to SpA, irrespective of demographic factors, disease duration and type of treatment. Conventional confounders such as age, gender, disease duration, therapy could not explain the difference. The cause for this increase is not known but might be specifically disease related and further research to understand the epidemiological and molecular causes hereof is necessary.