Nail involvement in psoriatic arthritis patients is an independent risk factor for carotid plaque

Abstract

Psoriatic arthritis (PsA) is a chronic, inflammatory and immunemediated disease that affects up to 30% of psoriasis (PsO) patients. Nail involvement affects 80% of PsA patients and 30%–50% of PsO patients. Nail PsO has been associated with worse quality of life, higher score on the PsO Area Severity Index, early disease onset, arthritis, depression and anxiety. Patients with PsO and PsA have a higher risk of cardiovascular atherosclerotic morbidity and mortality than the general population. Nail PsO and cardiovascular disease have been seldom studied. Nail involvement in PsO patients has been associated to a higher prevalence of metabolic syndrome, higher risk of heart failure and higher cardiovascular risk overall. 4 If PsA patients with nail PsO also have a higher cardiovascular risk is unknown. We aimed to determine if nail involvement in PsA patients is associated with a higher prevalence of subclinical atherosclerosis by carotid ultrasound. We performed a crosssectional, observational and comparative study that included a total of 64 PsA patients consecutively recruited from a Preventive CardiologyRheumatology Clinic cohort of the University Hospital ‘Dr. José E. González’ in Monterrey, Mexico. Patients included in the cohort were 30–75 years old that fulfilled the 2006 Classification Criteria for Psoriatic Arthritis. All PsA patients with nail involvement were included and patients without nail involvement were matched by age, gender and type 2 diabetes mellitus diagnosis. Patients with a previous cardiovascular atherosclerotic disease were excluded. A Bmode carotid ultrasound was performed in all study subjects by a boardcertified radiologist blinded to clinical information. Carotid plaque (CP) was defined as a carotid intima– media thickness (cIMT) ≥1.2 mm or a focal narrowing ≥0.5 mm of the surrounding lumen, and an increased cIMT was defined as a value ≥0.8 mm. Nail PsO Severity Index (NAPSI) was assessed in all patients. Distribution was evaluated with the KolmogorovSmirnov test. Comparisons were done with χ test for qualitative variables and Student’s ttest or MannWhitney’s U test for quantitative variables. Correlation between NAPSI and cIMT (using 1.2 mm as the value of cIMT in patients with CP) was determined with Spearman’s rank correlation coefficient (r). A p<0.05 was considered statistically significant. A total of 64 patients were included (32 in each group). Clinical and demographic characteristics are shown in table 1. CP was significantly more prevalent in PsA patients with nail involvement (53.1% vs 25.0%, p=0.021). PsA patients with nail involvement also had higher cIMT values (0.85 mm vs 0.59 mm, p=0.026). Spearman’s r showed a significant medium positive correlation between NAPSI and cIMT (r=0.314, p=0.012). A binary logistic regression, including traditional cardiovascular risk factors (hypertension, dyslipidaemia, obesity, active smoking, C reactive protein and erythrocyte sedimentation rate) demonstrated that nail involvement is an independent risk factor for the presence of CP with an OR 6.64 (95% CI: 1.71 to 25.74) (p=0.006). Our results showed that nail involvement in PsA patients is independently associated to CP. This could be explained by the fact that nail involvement has been linked to severe skin manifestations and joint involvement, resulting from an increased inflammatory burden, that is, directly associated with the development of atherosclerosis. In conclusion, PsA patients with nail involvement had a higher rate of CP and higher cIMT values than patients with PsA without it. Systematic evaluation of nail involvement in PsA patients may help identify highrisk individuals. More studies with a higher sample are necessary to confirm our findings and determine the precise role of carotid ultrasound evaluation in this population.