Inflammation, disease duration and delayed diagnosis associated with hypertension in axial spondyloarthritis

Axial spondyloarthritis (axSpA) patients with a higher inflammatory burden, longer delay in diagnosis and longer baseline disease duration (BLDD) have an increased risk of developing incident hypertension after adjusting for traditional cardiovascular (CV) risk factors, a retrospective cohort study by the Chinese University of Hong Kong has shown.  

Hypertension is the most prevalent comorbidity in axSpA, occurring in up to a quarter of all patients. [Rheumatol (Oxford) 2020;59:iv47-iv57] Systemic inflammation accelerates the development of premature atherosclerosis in axSpA, resulting in endothelial dysfunction, arterial stiffness, and impaired vascular wall homeostasis, which subsequently lead to elevated blood pressure and cardiac damage. [Arthritis Care Res (Hoboken) 2020;72:1645-1652]

A total of 413 axSpA patients (median age, 34 years; male, 77.2 percent) treated at a university clinic in Hong Kong from 2011 to 2019 were recruited into the study. Patients with hypertension and/or antihypertensive drug use at baseline were excluded. [Clin Exp Hypertens 2023;45:2205056]

After a median follow-up of 12 years, 14 percent of patients developed incident hypertension, defined as either systolic blood pressure (BP) ≥140 mm Hg or diastolic BP ≥90 mm Hg on two consecutive visits, or initiation of antihypertensive medication during subsequent follow-up. Those who developed incident hypertension had a significantly higher prevalence of CV risk factors (including older age, higher systolic and diastolic BP, cholesterol, fasting glucose levels and traditional CV risk scores) and inflammatory burden (longer disease duration and delay in diagnosis, higher erythrocyte sedimentation rate [ESR], and prevalence of active disease with Bath ankylosing spondylitis disease activity index [BASDAI] score ≥4).

In multivariate Cox regression models, BLDD (hazard ratio [HR], 1.15; 95 percent confidence interval [CI], 1.02–1.30; p=0.022) and delay in diagnosis (HR, 1.51; 95 percent CI, 1.15–1.97; p=0.003) remained significant after adjustment for age, sex, and body mass index (BMI). In univariate Cox regression, higher levels of inflammation (ESR ≥20 mm/hr) over time predicted incident hypertension with HR of 2.77 (95 percent CI, 1.29–5.94). In the fully adjusted model, BLDD (HR, 1.14), delay in diagnosis (HR, 1.45–1.48), and higher ESR level (HR, 1.03) were significantly associated with higher risk of developing incident hypertension.

“These data highlight the importance of early diagnosis and treatment in minimizing not only joint damage, but also CV risk. It is noteworthy that the risk of incident hypertension was significantly increased in patients with disease duration of >5 years, suggesting that routine screening for hypertension should be considered, especially in patients with longer disease duration,” advised the researchers.

During follow-up, 85.7 percent, 39.0 percent, 15.5 percent, and 38.5 percent of patients were identified as users of NSAIDs, sulphasalazine (SSZ), methotrexate, and biologic disease-modifying antirheumatic drugs (DMARDs). While in the univariate Cox regression analysis increased exposure to paracetamol and conventional synthetic DMARDs (especially SSZ) was significantly associated with a higher risk of developing incident hypertension, there was no association in the fully adjusted model.

The researchers highlighted that the relationship between drugs used to target inflammation in axSpA and the risk of developing hypertension remains controversial. There was a relatively low exposure to biologic DMARDs in the present study, but use of anti-inflammatory drugs in general was not associated with developing incident hypertension.