Association of Serum Uric Acid Concentration With Metabolic Risk Factors in Patients With Type 2 Diabetes

To the Editor:

We read the recent article by Marotta and colleagues1 with great interest. This study assessed the association of hyperuricemia with conventional cardiovascular risk factors in elderly patients and indicated that uric acid (UA) clusters in a sex‐specific fashion with features of the metabolic syndrome.1 A recent meta‐analysis of cohort studies showed that serum UA levels are positively associated with incidence of impaired fasting glucose and type 2 diabetes.2 However, the association of serum UA concentration with metabolic risk factors such as glycemic control and obesity in patients with type 2 diabetes remains unknown.

We studied correlations of serum UA concentration with body mass index (BMI), waist circumference, fat areas measured by abdominal computed tomography, blood pressure, fasting plasma glucose (FPG), glycated hemoglobin (HbA_1c), and fasting serum lipid levels in 47 patients with type 2 diabetes.

We could not find any significant correlations of serum UA concentration with metabolic risk factors in all patients. We divided patients into men (n=27) and women (n=20) and studied correlations of serum UA concentration with each parameter. The mean±standard deviation of age, height, weight, BMI, systolic and diastolic BPs, FPG, and HbA_1c in patients were 63.7±12.0 years and 66.3±10.7 years, 163.7±7.7 cm and 153.0±6.3 cm, 65.1±12.3 kg and 65.1±16.9 kg, 24.2±3.7 kg/m² and 27.5±5.5 kg/m², 138.7±18.5mm Hg and 133.4±13.8 mm Hg, 78.6±10.7 mm Hg and 77.9±10.3 mm Hg, 149.0±41.7 mg/dL and 129.7±24.2 mg/dL, and 6.9%±1.0% and 6.6%±0.6% in men and women, respectively.

Serum UA concentration was significantly and inversely correlated with BMI, waist circumference, total fat area, subcutaneous fat area, and HbA_1c in men with type 2 diabetes (Table). However, any significant correlations of serum UA concentration with these metabolic parameters were not observed in women with type 2 diabetes. We observed no significant correlations of serum UA concentration with systolic and diastolic BPs, visceral fat area, FPG, and serum lipid levels in both men and women.

Table 1.

Correlations of Serum Uric Acid Concentration With Cardiovascular Risk Factors in Men and Women With Type 2 Diabetes

	Men (n=27)		Women (n=20)
	r	P Value	r	P Value
Body mass index	−0.444	.020	−0.145	.541
Waist circumference	−0.523	.005	−0.102	.667
Systolic blood pressure	−0.012	.954	−0.070	.769
Diastolic blood pressure	−0.04	.843	−0.287	.221
Total fat area	−0.400	.039	−0.188	.427
Subcutaneous fat area	−0.497	.009	−0.051	.830
Visceral fat area	−0.351	.071	−0.359	.120
Fasting plasma glucose	−0.156	.437	0.063	.792
Glycated hemoglobin	−0.608	.001	0.006	.981
Triglycerides	−0.295	.136	0.225	.341
LDL cholesterol	−0.027	.895	0.142	.551
HDL cholesterol	0.311	.114	−0.206	.383

Abbreviations: HDL, high‐density lipoprotein; LDL, low‐density lipoprotein. r indicates Spearman's rank correlation coefficient. Total, subcutaneous, and visceral fat areas were measured by abdominal computed tomography.

The association between serum UA concentration and cardiovascular risk factors remains controversial, possibly and partially as a result of the differences between sexes. Marotta and colleagues1 reported that elderly women with higher UA levels (>5.5 mg/dL) had higher BMI, waist circumference, and serum glucose and triglyceride concentrations than women with lower UA levels, which was not observed in elderly men. Their study suggested that serum UA was unfavorably associated with cardiovascular risk factors in elderly women, which was not shown in men. Our study showed that serum UA was favorably associated with men with type 2 diabetes, which was not observed in women. Both studies demonstrated a significant difference between sexes in correlations of serum UA with cardiovascular risk factors.

The limitation of our study was that the number of patients was small. To elucidate our hypothesis, further studies, preferably with larger numbers of patients, will be needed.

Our study showed that serum UA was significantly and inversely correlated with BMI, waist circumference, fat area, and HbA_1c in men with type 2 diabetes. This study also presented sex differences in correlations of serum UA with cardiovascular risk factors.