Current Usage of Diuretics Among Hypertensive Patients in Japan: the Japan Home Versus Office Blood Pressure Measurement Evaluation (J-HOME) Study
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857 Hypertens Res Vol.29 (2006) No.11 p.857-863 Original Article Current Usage of Diuretics among Hypertensive Patients in Japan: The Japan Home versus Office Blood Pressure Measurement Evaluation (J-HOME) Study Kayo MURAI1), Taku OBARA2),3), Takayoshi OHKUBO1),3), Hirohito METOKI2),3), Takuya OIKAWA2), Ryusuke INOUE3), Rie KOMAI2), Tsuyoshi HORIKAWA2), Kei ASAYAMA1), Masahiro KIKUYA2), Kazuhito TOTSUNE2),3), Junichiro HASHIMOTO1),3), and Yutaka IMAI2),3), the J-HOME Study Group* In the Japan Home versus Office Blood Pressure Measurement Evaluation (J-HOME) study, we examined the current situation with respect to the prescription of diuretics, including the prevalence of diuretic treatment and the dosages used for patients with essential hypertension in primary care settings. Of the 3,400 hyper- tensive patients included in the study, 315 (9.3%) patients (mean age: 66.9±10.4 years; males: 43.5%) were prescribed diuretics. Compared with patients who were not using diuretics, those who were using diuretics were more obese and had more complications. The most commonly prescribed diuretic among the 331 pre- scriptions in the 315 diuretic users was trichlormethiazide (44%), followed by indapamide (15%) and spirono- lactone (14%). Among patients being treated with diuretics, monotherapy was used in only 5% of patients; in the majority of patients combination therapy including diuretics (95%) was used. Relatively low dosages of diuretics were generally used. There was a difference between the actual dosages prescribed and those recommended by the Japanese Society of Hypertension (JSH) guidelines or the product information approved in Japan. Compared with previous estimates of the prevalence of diuretic use in hypertensives in Japan (4.0–5.4%), the rate in the J-HOME study (9.3%) was higher. This may be attributable at least in part to the results of the many published, large-scale intervention trials confirming the clinical significance of diuretics. Although a relatively high dosage is recommended in the diuretic product information and in the JSH guidelines, dosages of diuretics should be reconsidered in Japan. (Hypertens Res 2006; 29: 857–863) Key Words: diuretics, prescribed doses, hypertension From the 1)Departments of Planning for Drug Development and Clinical Evaluation, Tohoku University Graduate School of Pharmaceutical Sciences, Sendai, Japan; 2)Departments of Clinical Pharmacology and Therapeutics, Tohoku University Graduate School of Pharmaceutical Sciences and Medi- cine, Sendai, Japan; and 3)Tohoku University 21st Century COE Program “Comprehensive Research and Education Center for Planning of Drug Devel- opment and Clinical Evaluation,” Sendai, Japan. The study was designed, conducted, and interpreted by the investigators, independently of the sponsors. This work was supported by Grants for Scientific Research (15790293, 1654041) from the Ministry of Education, Culture, Sports, Science and Technology, Health Science Research Grants on Health Ser- vices (13072101, H12-Medical Care-002) from the Ministry of Health, Labor and Welfare, and by Nouvelle Place Inc., Japan. *See Appendix. Address for Reprints: Takayoshi Ohkubo, M.D., Ph.D., Departments of Planning for Drug Development and Clinical Evaluation, Tohoku University Graduate School of Pharmaceutical Sciences, Tohoku University Hospital, 1–1 Seiryo-cho, Aoba-ku, Sendai 980–8574, Japan. E-mail: [email protected] Received March 2, 2006; Accepted in revised form July 19, 2006. 858 Hypertens Res Vol. 29, No. 11 (2006) record the results over 2 weeks, as specified by the Japanese 13 Introduction guidelines for home BP measurement ( ). The patients used electronic arm-cuff devices that operate using the cuff-oscil- A recent study in the United States used data from the phar- lometric method. The mean of all measurements recorded macy system of the Health Maintenance Organization (HMO) over a 2-weeks period was calculated for each patient and to demonstrate that prescription of thiazide diuretics signifi- used for analysis. cantly increased after the results of the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial Office BP Measurements (ALLHAT) (1) were published (2). In Japan, it has been reported that the percentage of treated hypertensives being Office BP was measured twice consecutively in the sitting prescribed diuretics was only 4.0–5.4% for the period from position after a rest of at least 2 min at each office visit with 1999 to 2002 (3–5), but was 13.0–14.0% between 2003 and the patient’s treating physician. The physicians or nurses used 2004 (6, 7). However, the dosages of diuretics used were not either the auscultatory method with a mercury or an aneroid mentioned in these reports. Several studies have shown that sphygmomanometer, or the cuff-oscillometric method with even a low dosage of diuretics has a satisfactory effect on an electronic arm-cuff device. The office BP value that was hypertension (8–10). Therefore, it is important to evaluate the used for analysis for each patient was the average of four dosages of diuretics, as well as the prevalence of the use of measurements taken at two office visits during the time diuretics. The objective of the present study was to investigate period that home measurements were being carried out. the current usage of diuretics, including the prevalence and the dosages of diuretics used, in Japan from the Japan Home Data Collection and Statistical Analysis versus Office Blood Pressure Measurement Evaluation (J- HOME) study. Information on the characteristics of patients, on antihyper- tensive medications, on home BP and on office BP was pro- Methods vided by the attending physicians. Variables were compared by using Student’s t-test, ANOVA and χ2 test as appropriate. Data are shown as the mean±SD. Among the 315 patients Patients who received diuretics, 16 patients were prescribed two kinds Details of the methods used in this study have been described of diuretics. Therefore, the total number of diuretic prescrip- previously (11, 12). Briefly, in March 2003, 7,354 physicians tions was 331. The percentage of diuretics used represented randomly selected from all over Japan were invited to take the proportion among these 331 prescriptions. A p value less part in this project. Of the 1,477 who agreed to participate, than 0.05 was accepted as indicative of statistical signifi- 751 collected data for the study. By the end of August 2003, cance. All statistical analyses were conducted using the SAS 3,586 patients who gave their informed consent to participate package (version 9.1; SAS Institute, Cary, USA). in the study were enrolled. We asked each doctor to enroll 5 patients. Most doctors (79.3%) enrolled 5 patients or fewer Results (mean 4.7, median 5, mode 5, range 1–25). About half of the doctors enrolled 5 patients. The proportion of doctors who Of the 3,400 hypertensive patients, 315 (9.3%) patients (mean enrolled 1 or 2 patients was 11.1%, 3 or 4 patients was 21.3%, age: 66.9±10.4 years; males: 43.5%) were being treated with 5 patients was 46.9%, 6 or 7 patients was 19.7%, and 8 or diuretics. The characteristics of patients treated and not more patients was 0.9%. Of those, 66 were excluded because treated with diuretics are shown in Table 1. With respect to their blood pressure (BP) levels were within normal ranges the sub-classes of diuretics used, thiazide diuretics was the without being treated with antihypertensive medication. An most commonly used (45.0%), followed by thiazide-like additional 120 patients were excluded because insufficient diuretics (22.4%), loop diuretics (13.6%), and potassium- data on BP values or patient characteristics were provided. sparing diuretics (9.4%). In patients not being treated with Thus, the study population consisted of 3,400 hypertensive diuretics, the mean home diastolic BP was significantly patients. Of the 3,400 patients, 315 (9.3%) were prescribed higher (81.8 vs. 80.4 mmHg, p<0.02) and the mean body diuretics. The study protocol was approved by the Institu- mass index was significantly lower (23.7 vs. 24.3 kg/m2, tional Review Board of Tohoku University School of Medi- p<0.003) than in patients being treated with diuretics. cine. Patients being treated with diuretics had significantly higher prevalence of renal disease (8.6% vs. 4.8%, p=0.004), hyper- cholesterolemia (46.0% vs. 39.6%, p=0.03), and high uric Home BP Measurements acid (18.7% vs. 10.8%, p<0.001) than patients not being Patients were asked to measure their BP once every morning treated with diuretics. Diuretics were used in 8.6% of patients within 1 h of waking, in the sitting position after 2 min or with stroke. With regard to patients treated with diuretics, eld- more of rest, before drug ingestion and breakfast, and to erly patients with many complications often received loop Murai et al: Current Usage of Diuretics in Japan: J-HOME Study 859 Table 1. Comparison of Patients’ Characteristics According to Diuretics Ingestion With diuretics Without diuretics (n=315 [9.3%]) (n=3,085 [90.7%]) Thiazide Thiazide-like Loop Potassium-sparing Total (n=149 (n=74 (n=45 p*-value Total p**-value (n=31 [9.4%]†) [45.0%]†) [22.4%]†) [13.6%]†) Age (years) 66.9±10.4 66.9±9.7 65.2±10.4 70.2±10.0 64.2±12.1 0.03 66.1±10.5 0.2 Men (%) 43.5 43.0 39.2 40.0 48.4 0.8 44.9 0.6 Home BP Systolic (mmHg) 138.7±13.7 139.4±13.6 137.4±13.4 142.3±15.5 135.4±13.0 0.1 139.7±13.8 0.2 Diastolic (mmHg) 80.4±9.9 81.2±9.0 82.6±10.0 76.5±11.0 80.0±9.8 0.008 81.8±9.5 0.02 Office BP Systolic (mmHg) 141.9±14.9