Early Chronic Kidney Disease (G1-G3a) in Combination with Steatosis as a Predictor of Incident Ischemic Heart Disease: A Longitudinal Study in Non-Diabetic Koreans

The Combination of Uric Acid and Hemoglobin Levels Predicts the Incident Risk of Ischemic Heart Disease More Than Uric Acid Alone in Non-Diabetic Koreans: A Longitudinal Study Using National Health Insurance Data

Uric acid has been related to cardiovascular disease (CVD). Recently, slightly elevated hemoglobin (Hb) was also shown to be associated with CVD. We retrospectively investigated the joint effect of uric acid and elevated Hb by comparing normal-range uric acid alone on incident ischemic heart disease (IHD) risk in a large cohort of non-diabetic Korean adults using National Health Insurance data. We assessed 16,786 participants without diabetes (8595 men and 8191 women) using extensive cohort data. High Hb was defined as ≥16.4 g/dL in men and 13.8 g/dL in women (>75th percentile). We analyzed the data using two different methods. First, the participants were divided into quartiles according to uric acid levels. Second, subjects were also divided into quartiles: reference (group 1), high uric acid and normal Hb (group 2), normal uric acid and high Hb (group 3), and normal uric acid and high Hb (group 4). We evaluated hazard ratios (HRs) with 95% confidence intervals (CIs) for IHD using multivariate Cox regression analysis over a 50-month follow-up. During the follow-up, 345 (1.9%) participants developed IHD. In the analysis using both uric acid and Hb, compared with the reference group, the HRs for IHD were 1.37 (95% CI, 1.01-1.86) in the second group, 1.63 (95% CI, 1.21-2.21) in the third group, and 1.86 (95% CI, 1.30-2.67) in the fourth group after adjusting for IHD risk factors. Subsequently, patients with high uric acid are more likely to develop incident IHD than control patients. Moreover, we confirmed the joint effects of high uric acid and high hemoglobin on incident IHD. Awareness of these interactions is essential for clinicians. Risk factor management and screening for IHD are part of the routine management of patients with high uric acid and Hb.

Elevated Uric Acid Levels with Early Chronic Kidney Disease as an Indicator of New-Onset Ischemic Heart Disease: A Cohort of Koreans without Diabetes

Several studies have showed that hyperuricemia is related to the development of ischemic heart disease (IHD). There is also growing evidence indicating that hyperuricemia may contribute to the progression of IHD as a pathogenic factor. Ironically, uric acid can be an antioxidant agent, as shown in experimental studies. The aim of our study is to analyse the association between uric acid and IHD with early-stage chronic kidney disease (CKD). Data were assessed from 17,492 participants without cardiovascular disease from the Korean Genome and Epidemiology Study (KoGES) and Korea Health Insurance Review and Assessment (HIRA) data. The subjects were categorized as four groups according to CKD and uric acid levels. We retrospectively evaluated hazard ratios (HRs) with 95% confidence intervals (CIs) for IHD by using multivariate Cox regression analysis over a 4-year period from the baseline survey. During the follow-up, 335 individuals (3.4%; 236 men and 99 women) developed IHD. Compared to the participants without elevated uric acid and early CKD HRs for incident IHD according to uric acid levels and early CKD, the uric acid level was 1.13 (95% CI, 0.86-1.48) in participants with elevated uric acid and without early CKD, 0.99 (95% CI, 0.55-1.77) in participants without elevated uric acid and with early CKD, and 1.65 (95% CI, 1.03-2.66) in participants with elevated uric acid and early CKD after adjusting for confounding metabolic factors. Early CKD and high uric acid levels increased the risk of new-onset IHD (HR, 1.65; 95% CI, 1.03-2.66). Elevated uric acid levels were related to an increased risk of incident IHD in early-stage CKD patients. It is expected that uric acid can be a reliable predictor for IHD, even in early-stage CKD patients; thus, in those with CKD, proactively managing uric acid levels can play a significant role in reducing the risk of cardiovascular disease.

Longitudinal Effects of Serum Calcium and Phosphate Levels and Their Ratio on Incident Ischemic Heart Disease among Korean Adults

Serum calcium and phosphate levels are controlled by a regulatory system, but their individual concentration tendencies and interactions may affect long-term vascular health. This study aimed to assess the effects of serum calcium and phosphate levels on incident ischemic heart disease (IHD) in a large-scale community-dwelling Korean cohort. We evaluated 15,259 non-diabetic individuals (median age, 45 years; range, 30–85) without previous IHD or ischemic stroke using the Korean National Health Insurance data. The study population was classified based on the calcium, phosphate, and calcium/phosphate ratios. Using Cox proportional hazards regression models, we estimated hazard ratios (HRs) with 95% confidence intervals (CIs) for IHD over 50 months after baseline enrolment. The age- and sex-adjusted incidence of IHD gradually increased with serum calcium and phosphate quartiles and decreased with calcium/phosphate ratio quartiles, with an overall crude rate of 2.1% (315/15,259). After setting the lowest calcium, phosphate, and calcium/phosphate ratio quartiles as a reference group, the HRs (95% CIs) of the highest calcium, phosphate, and calcium/phosphate ratio quartiles for IHD were 1.77 (1.15–2.72), 1.73 (1.18–2.55), and 0.58 (0.39–0.87), respectively, after adjusting for potential confounding variables. Serum calcium and phosphate levels were positively associated with IHD incidence, while the serum calcium/phosphate ratio exhibited an inverse relationship. Serum calcium and phosphate homeostasis may merit serious consideration to understand the pathogenesis of coronary atherosclerosis as a risk modifier for IHD.