Higher Incidence Rates of Comorbidities in Patients with Psoriatic Arthritis Compared with the General Population Using U.S. Administrative Claims Data.

BACKGROUND

Psoriatic arthritis (PsA) is associated with multiple comorbid conditions, including cardiovascular (CV) comorbidities that impose a considerable burden on patients. Effective management of PsA requires an understanding of comorbidity profiles.

OBJECTIVE

To compare the frequency and incidence rates of comorbidities and hospitalizations among newly diagnosed PsA patients and a matched general population without PsA, using large national claims databases in the United States.

METHODS

This retrospective observational study used MarketScan databases from January 1, 2008, to September 30, 2015, to identify adult patients with newly diagnosed PsA (i.e., no PsA diagnosis during the 1 year before the first observed PsA diagnosis). The earliest date of PsA diagnosis was defined as the index date. Patients with no PsA diagnosis any time during the study period (controls) were directly matched to PsA patients with demographic characteristics. All patients had ≥ 2 years of medical and pharmacy coverage before the index date and ≥ 1 year of follow-up. Incident rates per 100 person-years for comorbidities of interest were evaluated. The hazard ratios of having various comorbid conditions for PsA patients were estimated by Cox proportional hazards models. All-cause and CV-related hospitalizations during the follow-up period were evaluated.

RESULTS

A total of 14,898 PsA patients and 35,037 matched controls met the study criteria. Compared with controls, PsA patients had a higher risk of CV disorders (incidence rate = 6.5 vs. 5.8; HR = 1.46; 95% CI = 1.37-1.56) and a higher risk of the majority of the specific CV disorders (hypertension, hyperlipidemia, coronary artery disease, cerebrovascular disease, peripheral vascular disease). PsA patients also had a higher risk for any autoimmune disease (incidence rate = 8.4 vs. 1.6; HR = 18.26; 95% CI = 17.18-19.40) and most autoimmune categories (psoriasis, ankylosing spondylitis, rheumatoid arthritis, multiple sclerosis, and other autoimmune disorders). Rates of other PsA-related comorbidities (diabetes, anxiety, fatigue, smoking, alcohol use, obesity or overweight, depression, osteoporosis, uveitis, eczema, and gout) were also significantly higher for PsA patients. The all-cause hospitalization rate was higher among PsA patients than controls (24.9% vs. 16.2%; P < 0.001). The CV-related hospitalization rate varied depending on whether the CV condition was the primary discharge diagnosis only or was any diagnosis on the inpatient claims. The rates of coronary artery disease hospitalizations were significantly higher in PsA patients than in controls with both methods of analysis (primary diagnosis: 0.8% vs. 0.5%; P < 0.001; nonprimary diagnosis: 3.2% vs. 2.2%; P < 0.001).

CONCLUSIONS

This retrospective U.S.-based claims study found that PsA patients had a high comorbidity burden. Compared with the non-PsA population, PsA patients were associated with a higher incidence of CV comorbidities, autoimmune diseases, and other PsA-related comorbidities and a higher rate of all-cause and CV-related hospitalizations. Understanding these comorbidity profiles may provide insight on the effect of comorbid conditions on disease management and health care utilization associated with PsA.

UNASSIGNED

This study was funded by Novartis. Kaine is a paid consultant for Novatis. Hur and Palmer are Novartis employees and stockowners. Song and Kim work for Truven Health Analytics, which received funding from Novartis to conduct this study.