New comorbidity tool predicts risk of hospitalisation and death in psoriatic arthritis

The results of a study presented today at the European League Against Rheumatism Annual Congress (EULAR 2016) showed that a newly developed method of evaluating the impact of different comorbidities in patients with Psoriatic Arthritis (PsA) can be used to prospectively identify those PsA patients at greater risk of hospitalisation and premature death. In addition to helping predict the future use of resources and identify targets to reduce costs, application of this new PsA-comorbidity index may ultimately improve outcomes for PsA patients.

"To date, no disease-specific models had been developed to identify those comorbidities with the greatest impact on PsA patients' health status," said Dr Yasser El Miedany of the Department of Rheumatology, Darent Valley Hospital, UK. "We have now developed and validated a PsA-comorbidity index (PsACI), which will enable clinicians to prospectively include comorbidities assessment and management in their standard practice.

"Once our research has been published, we suggest this new tool is included as part of the patient-reported outcome measures used in standard clinical practice. By making PsACI available to rheumatologists worldwide, we hope it will prove an effective guide to optimising the management of Psoriatic Arthritis," Dr Yasser El Miedany concluded.

PsA, an inflammatory arthritis associated with joint pain and swelling which can lead to joint damage and long-term disability, is a common complication of psoriasis. Psoriasis occurs in 1-3% of the population, and the estimated prevalence of PsA among psoriasis patients varies widely from 6-42%, due to heterogeneity in study methods and the lack of widely accepted classification or diagnosis criteria. Due to dual skin and joint involvement, patients with PsA experience further impairment and consequently a lower quality of life compared with patients with psoriasis alone.

Besides skin and joint involvement, PsA is associated with multiple comorbidities, including metabolic syndrome (hyperlipidaemia, hypertension, diabetes mellitus, and obesity), other autoimmune diseases (e.g. inflammatory bowel disease), and lymphoma. In addition, this burden of physical comorbidities,

which increases with the severity of the psoriasis and with the presence of severe PsA, increases mortality.2

A retrospective multicentre analysis of 1,707 PsA patients, monitored over a 10-year period, assessed the impact of different comorbidities on predicting future death and hospitalisation. To develop a morbidity index score, different cut-off values were identified to delineate patients at different stages of risk of hospitalisation and death.

Those PsA patients who had a higher incidence of comorbid conditions and were at higher risk of hospitalisation were men, with older age at disease onset, and a high BMI at baseline (p < 0.05). The most prevalent comorbidities strongly associated with a 10-year risk of death or hospitalisation in PsA patients were: cardiovascular (seven different comorbidities), osteoporosis, falls, depression / anxiety, diabetes mellitus, renal and liver diseases, lung and GI problems, as well as infection (p < 0.001).

A Multidimensional Disease Severity score as an independent predictor of disease status (based on 5 different indicators of disease activity (DAPSA, PASI , Functional disability score, enthesitis and ESR /CRP ) was shown to be significantly associated with the 10-year risk of death or hospitalisation (p=0.002). Male gender, cardiovascular disease, evidence of a risk of falls, diabetes, infection, anxiety, and this MDR score were all significant independent factors affecting the outcome of the disease at 10 years.

The PsA comorbidity index weighted according to analysis of the above variables produced a score that ranged from 0 to 36, with a cut-off point of 14.5 associated with a sensitivity of 97.5% and a specificity of 87%.