Status of Uric Acid Management in Hypertensive Subjects

549 Hypertens Res Vol.30 (2007) No.6 p.549-554 Original Article Status of Uric Acid Management in Hypertensive Subjects Yasutaka YAMAMOTO1), Koichi MATSUBARA2), Go IGAWA2), Yasuhiro KAETSU3), Shinobu SUGIHARA1), Takashi MATSUURA1), Fumihiro ANDO1), Kazuhiko SONOYAMA2), Toshihiro HAMADA2), Kazuhide OGINO2), Osamu IGAWA2), Chiaki SHIGEMASA3), and Ichiro HISATOME1) Hyperuricemia in hypertensive subjects has been considered one of risk factors of cardiovascular diseases. We investigated the status of uric acid management in 799 hypertensive subjects (432 females and 367 males; mean age 70.9 years) managed by 43 doctors (19 cardiologists and 24 noncardiologists; 25 private practice doctors and 18 hospital doctors). The serum uric acid level was available in 85.7% of the patients. This availability was equivalent regardless of facility size, and more cardiologists than noncardiologists monitored this information. The prevalence of hyperuricemia was 17.5% and was higher in men and in patients with high triglyceridemia, left ventricular hypertrophy, renal dysfunction, proteinuria, and smokers, but was not higher in subjects with chronic heart failure, diabetes mellitus, and those with prescriptions for diuretics and β-blockers. The average serum uric acid level was higher in men and patients with chronic heart failure, renal dysfunction, high triglyceridemia, low high-density cholesterolemia, smokers, and subjects prescribedβ-blockers. Fifty percent of hyperuricemic patients were medicated, and 48.6% of them cleared the uric acid target level (6 mg/dL). No differences were observed in the treatment rate or the achievement rate of the target between genders, concurrent diseases, and physician specialties. Although doctors, especially cardiologists, have a high concern for the serum uric acid level, they do not intervene intensively, and specific treatment for individual patterns is not routinely given. Thus, more attention to uric acid management is necessary in hypertensive subjects to prevent cardiovascular diseases. ( Hypertens Res 2007; 30: 549–554) Key Words: hyperuricemia, hypertension, uric acid, cross-sectional investigation Introduction Average serum uric acid levels and hyperuricemia prevalence are higher in hypertensive subjects than in normotensive subjects (1, 2). Whether or not hyperuricemia is an independent risk factor for cardiovascular diseases (CVDs) has been debated; however, it is widely recognized as a good indicator of the incidence of CVDs (3–6). Especially in hypertensive subjects, several epidemiological studies have suggested that hyperuricemia may be an independent risk factor for CVDs (6, 7–9). Hyperuricemia per se has been reported to increase blood pressure (10–12) and to stimulate vascular smooth muscle proliferation and vascular remodeling (13, 14). Thus, the management of hyperuricemia in hypertensive subjects has been considered an important candidate to decrease the From the 1)Division of Regenerative Medicine and Therapeutics, Tottori University Graduate School of Medical Sciences, Yonago, Japan; 2)Department of Cardiovascular Medicine, Tottori University Hospital, Yonago, Japan; and 3)Department of Multidisciplinary Internal Medicine, Tottori University Faculty of Medicine, Yonago, Japan. Address for Reprints: Yasutaka Yamamoto, M.D., Ph.D., Division of Regenerative Medicine and Therapeutics, Tottori University Graduate School of Medical Sciences, 36–1 Nishi-machi, Yonago 683–8504, Japan. E-mail: Received October 20, 2006; Accepted in revised form January 25, 2007. 550 Hypertens Res Vol. 30, No. 6 (2007) incidence. In Japan, guidelines for the management of hyperuricemia and gout were announced by the Japanese Society of Gout and Nucleic Acid Metabolism in 2002, and careful management of the serum uric acid level was proposed (15). There are few data on how doctors in Japan manage hyperuricemia in hypertensive subjects. We assessed the present status of uric acid management in hypertensive subjects and whether or not better management is necessary. In this study, we surveyed the serum uric acid level, the prevalence of hyperuricemia, and the treatment of hyperuricemia in hypertensive subjects, and we investigated the characteristics of subjects who should have their serum uric acid levels closely managed. Methods Study Design A cross-sectional survey was performed for 6 months (from April to September 2005). The study protocol was approved by the Ethics Committee of Tottori University Hospital, and all of the participants followed this protocol. Forty-three doctors in 38 facilities participated in this survey (19 cardiologists: 11 at hospitals and 6 in private practice; and 24 noncardiologists: 5 at hospitals and 19 in private practice). In 2000, we investigated the serum uric acid management of 907 hypertensive subjects by cardiologists (16) and found that the examination rate of serum uric acid level varied substantially depending on the size of the facility (unpublished data). Therefore we compared differences in facility size and physician specialty in this investigation. A total of 799 hypertensive subjects were enrolled in this study. Hypertensive patients treated for at least 6 months prior to this survey were included. Patients treated without antihypertensive drugs were also enrolled. Excluded were patients who had been diagnosed with white coat hypertension or who had current prescriptions for antihypertensive drug(s) not for lowering blood pressure. Each participating doctor was asked to enroll consecutive outpatients who had given informed consent to participate in this study. The participating doctors were asked to complete a survey detailing how each hypertensive patient was treated. Questions for which data were unavailable were left blank; thus, a blank response indicates “no examination” or “no concurrent disease.” Study Details and Definitions Data on age, gender, blood pressure, family history, risk factors, prescription(s), and concurrent diseases (including CVDs, cerebrovascular diseases, and renal insufficiency) were collected. Prescription details (dose, duration) were not asked except for the name of the prescription drug. Blood pressure was the mean of the blood pressure measured on the three most recent visits. Hypertension was defined as a systolic blood pressure (SBP) ≥ 140 mmHg and/or diastolic Table 1. Patient Characteristics A: Doctor/Facility Subjects Age (years) Total Hospital Cardiologist Non-cardiologist Private clinic Cardiologist Non-cardiologist 685 298 243 55 387 126 261 70.9 ± 10.3 70.1 ± 11.0 69.4 ± 11.3 73.2 ± 8.8 71.0 ± 9.7 72.9 ± 8.3 70.1 ± 10.2 Female (n = 370) Male (n = 315) Age (years) 72.1 ± 10.1 Body mass index (kg/m2) 23.9 ± 3.6 Uric acid (mg/dL) 4.8 ± 1.2 LDL cholesterol (mg/dL) 117.4 ± 24.2 HDL cholesterol (mg/dL) 61.0 ± 15.7 Triglyceride (mg/dL) 115.4 ± 54.1 Fasted blood sugar (mg/dL) 103.3 ± 25.3 Smoking (%) 2.4 68.9 ± 10.2 23.7 ± 3.1 5.9 ± 1.3 109.7 ± 28.3 55.9 ± (...truncated)