Prescribing of Antihypertensive Agents in Public Primary Care Clinics - is it in Accordance with Current Evidence?

BACKGROUND: Large population surveys in Malaysia have consistently shown minimal improvement of blood pressure control rates over the last 10 years. Poor adherence to antihypertensive medication has been recognized as a major reason for poor control of hypertension. This study aimed to describe the prescribing pattern of antihypertensive agents in 2 public primary care clinics and assess its appropriateness in relation to current evidence and guidelines.
METHODS: A cross-sectional survey to describe the prescribing pattern of antihypertensive agents was carried out in 2 public primary care clinics in Selangor from May to June 2009. Hypertensive patients on pharmacological treatment for ?1 year who attended the clinics within the study period of 7 weeks were selected. Appropriate use of antihypertensive agents was defined based on current evidence and the recommendations by the Malaysian Clinical Practice Guidelines (CPG) on the Management of Hypertension, 2008. Data were obtained from patients' medical records and were analysed using the SPSS software version 16.0.
RESULTS: A total of 400 hypertensive patients on treatment were included. Mean age was 59.5 years (SD ±10.9, range 28 to 91 years), of which 52.8% were females and 47.2% were males. With regards to pharmacotherapy, 45.7% were on monotherapy, 43.3% were on 2 agents and 11.0% were on ≥3 agents. Target blood pressure of <140/90mmHg was achieved in 51.4% of patients on monotherapy, and 33.2% of patients on combination of ≥2 agents. The commonest monotherapy agents being prescribed were β-blockers (atenolol or propranolol), followed by the short-acting calcium channel blocker (nifedipine). The commonest combination of 2-drug therapy prescribed was β-blockers and short-acting calcium channel blocker.
CONCLUSION: This study shows that the prescribing pattern of antihypertensive agents in the 2 primary care clinics was not in accordance with current evidence and guidelines. β-blockers and short-acting preparations were commonly used both as monotherapy and combination treatment. Thiazide diuretics, ACE inhibitors and long acting calcium channel blockers were underutilised in this study, despite robust evidence to support their use. Evidence have also shown that simplifying the number of daily doses is effective in improving adherence, therefore a wider use of generic once daily preparation should be strongly advocated in public primary care clinics.