Introduction:
Inflammatory status could play a role in alterations of blood pressure (BP) circadian rhythm. The aim of our study is to compare levels of usual inflammatory markers in patients with and without circadian BP abnormalities.

Material and methods:
This is a cross-sectional design study with retrospective data analysis which included patients from an Internal Medicine Department with normal and high BP levels older than 18 years who were separated into two groups according to the circadian profile of BP (dipper and non-dipper) based on the results of 24-hour ambulatory BP monitoring. Patients were assessed for demographic characteristics and cardiovascular risk factors. We considered as inflammatory markers the platelet count (PTC), erythrocyte sedimentation rate (ESR), ultra-sensitive C-reactive protein, ferritin, fibrinogen, and uric acid.

Results:
The study included 551 patients (mean age of 54 years, 47% women). The non-dipper group had a higher percentage of individuals with higher ESR (OR = 1.77, 95% CI: 1.23–1.55, p = 0.001), uric acid (OR = 1.50, 95% CI: 1.04–2.16, p = 0.028) and fibrinogen (OR = 1.72, 95% CI: 1.18–2.51, p = 0.001) and a higher percentage of patients with higher PTC (OR = 0.54, 95% CI: 0.37–0.78, p = 0.005). These results were independent of age, waist circumference, presence of arterial hypertension, diabetes or hyperlipidemia, and use of antihypertensive drugs including renin angiotensin aldosterone system blockers.

Conclusions:
Patients with impaired circadian BP rhythm were associated with an unfavorable inflammatory status independently of BP levels. This fact could play a role in the prognostic differences observed between dipper and non-dipper patients.