Uric Acid/HDL Cholesterol Ratio and the Non-Dipping Blood Pressure Phenotype in Primary Hypertension

Objective: We examined whether nocturnal dipping status in primary hypertension varies according to the serum uric acid-to-high-density lipoprotein cholesterol ratio (UHR) and evaluated the ratio’s ability to distinguish patients classified as non-dippers from those classified as dippers.
Method: This retrospective cross-sectional study included 260 consecutive patients with primary hypertension and a finalized 24-hour ambulatory blood pressure monitoring (ABPM) report. Dipping status was obtained from the finalized clinical report. The UHR was calculated as serum uric acid divided by high-density lipoprotein cholesterol (HDL-C). Its adjusted association with non-dipping was estimated using multivariable logistic regression. Sensitivity analyses in the 182 participants with retrievable detailed ABPM data additionally adjusted for 24-hour or nighttime mean systolic and diastolic blood pressure. Receiver operating characteristic (ROC) analysis was used to quantify apparent in-sample discrimination.
Results: There were 132 dippers (50.8%) and 128 non-dippers (49.2%). Median UHR values were 0.111 [0.104–0.118] and 0.129 [0.123–0.141], respectively (P < 0.001). In the primary model, the odds ratio (OR) for a 0.01 increase in UHR was 2.922 (95% confidence interval [CI], 2.188–3.901; P < 0.001). In the 182 patients with detailed ABPM data, the association persisted after additional adjustment for 24-hour systolic and diastolic blood pressure (OR, 2.685; 95% CI, 1.911–3.773; P < 0.001) and, separately, for nighttime systolic and diastolic blood pressure (OR, 2.622; 95% CI, 1.512–4.548; P < 0.001). The apparent area under the ROC curve (AUC) was 0.855 (95% CI, 0.805–0.900); the exploratory threshold of 0.122 had a sensitivity of 78.9% and a specificity of 84.8%.
Conclusion: A higher UHR was associated with the non-dipping phenotype, including after adjustment for ambulatory blood pressure levels. These cross-sectional findings do not establish incremental clinical utility, and the observed discrimination and threshold require independent validation.

Keywords: Ambulatory blood pressure monitoring, circadian rhythm, high-density lipoprotein cholesterol, hypertension, uric acid