Use of antidiabetic and antihypertensive drugs in hospital and outpatient settings in Hong Kong.

OBJECTIVE: To investigate the usage patterns of antidiabetic and antihypertensive drugs and to identify any discordance between recommended management guidelines and clinical practice in two study locations. DESIGN: Prescription survey. SETTING: A government- operated general outpatient clinic (GOPC) and a medical/geriatric specialist clinic (SC) affiliated with a regional hospital in the same district. PATIENTS: Patients presenting with a prescription during the study period at the respective pharmacy were classified as having diabetes if at least one antidiabetic agent was prescribed and as having hypertension if a cardiovascular drug was prescribed in a hypotensive dosage. MAIN OUTCOME MEASURE: The pattern of use of antidiabetic and antihypertensive drugs. RESULTS: One thousand one hundred forty-four consecutive prescriptions were collected in the GOPC, and 1523 in the SC. Of 9.4% (n = 107) of patients were classified as having diabetes in the GOPC and 20.4% (n = 310) in the SC (p<0.001). Most patients with diabetes were taking oral hypoglycemic agents (98.1% in GOPC vs. 84.5% in SC). Glibenclamide was the sufonylurea used most often as monotherapy in both settings (50.5% in GOPC vs. 40.6% in SC). The combined use of a sulfonylurea with metformin was common in both settings (22.4% in GOPC vs. 28.4% in SC). Metformin monotherapy (1.9% in GOPC vs. 2.6% in SC) and combination treatment of insulin with an oral agent (0% in GOPC vs. 2.6% in SC) were rarely prescribed. In the GOPC, 24.5% (n = 280) of patients were prescribed an antihypertensive drug compared with 47.1% (n = 717) in the SC (p< 0.001). In the GOPC, the use of antihypertensive drugs was more prevalent in those with diabetes (53.5%) than in the remaining patients without diabetes (21.5%, p<0.001). In the SC, 51% of patients with diabetes were receiving antihypertensive drugs, but 40% of patients without diabetes were also receiving three treatments. In the GOPC, diuretics (indapamide 14.3% other 59%) and methyldopa (9.5%) were the most frequent choices of antihypertensive drugs when used as monotherapy in subjects without diabetes. In the SC, apart from diuretics (indapamide 12.9%, other 20.3%), beta-blockers (29%) also were prescribed frequently. If treated with only one antihypertensive drug, most patients with diabetes in the GOPC were prescribed indapamide (72.7%), and patients in the SC were treated mainly with angiotensin-converting enzyme inhibitors (35%) indapamide (22.5%), or calcium-channel blockers (13.8%). CONCLUSIONS: In this prescription-based survey, diabetes mellitus and hypertension were found to be common diseases in general practice and in a hospital SC. Oral hypoglycemic agents were the main from of antidiabetic therapy in both settings, with glibenclamide being the most commonly prescribed sulfonylurea. The types of antihypertensive drugs used were different in the two locations and varied according to the coexistence of type II diabetes mellitus. Despite some potential limitations, prescription-based surveys are an easy and economical method for surveying the occurrence of some common medical problems and the pattern of drug use in a fairly large number of patients in health institutions.