IMPACT OF AN ESSENTIAL DRUGS LIST AND TREATMENT GUIDELINES ON PRESCRIBING IN SOUTH AFRICA

1. IMPACT OF AN ESSENTIAL DRUGS LIST AND TREATMENT GUIDELINES ON PRESCRIBING IN SOUTH AFRICA Pillay T, Hill SR School of Medical Practice and Population Health, The University of Newcastle, Australia Prescription Audit Data: Monotherapy/Combination Therapy Abstract Problem Statement: In 1998, the South African health department introduced standard treatment guidelines for various medical conditions including hypertension. The impact of these guidelines on prescribing has not been assessed at provincial level. Objectives: To identify trends in antihypertensive medication use from supply data and patient prescription surveys. Design and Setting: Cross-sectional survey using supply data from the provincial medicines depot (PMSC) database to generate a 6-month summary report of antihypertensive supply. Thereafter antihypertensive prescription audits were conducted at selected public hospital pharmacy departments in the province of Kwazulu Natal (KZN). Study Population: The PMSC database was used to analyse drug supply data to the 63 KZN hospitals. Prescriptions for antihypertensive therapy presented by patients to public hospital pharmacy departments were used in the drug utilisation review. Methods: The PMSC database was used to generate a summary report of volumes of each antihypertensive supplied to KZN hospitals. This summary report was used to determine the relative usage of each antihypertensive, by hospital. Fifteen hospitals were selected for an audit of antihypertensive prescriptions. At each of the selected hospitals, 100 consecutive antihypertensive prescriptions presented to the hospital pharmacy departments were recorded into a database and later analysed. Results: Analysis of the supply data suggested that diuretics were the most widely prescribed, followed by ACEI, methyldopa, reserpine, calcium channel blockers and beta blockers. If prescribers complied with hypertension treatment guidelines, the usage pattern (declining order of volume) would have been diuretics, reserpine, beta blockers, ACEI, calcium channel blockers. Prescription audits at selected hospitals suggest that clinicians prescribe (in declining order of volume) diuretics, ACEI, calcium channel blockers, beta blockers, methyldopa, reserpine and hydrallazine. Conclusions: The study results demonstrate that supply data is useful in identifying prescribing trends that can be further quantified through prescription audits. This methodology would be most useful in resource-poor settings. Furthermore, analysis of drug supply data and the prescription audit suggest that prescribers in KZN public hospitals are not compliant with hypertension treatment guidelines. Methods (continued) • Drug supply data • The drug supply database was used to calculate the total volume of each antihypertensive drug supplied (as PRPs) to all provincial hospitals over a six month period, grouped into pharmacological class. • The proportion (%) of each drug class supplied to each hospital over the 6 month period was calculated. • Hospitals were ranked on the basis of their usage of methyldopa as high, medium and low prescribers of methyldopa. • Prescription audit data • 16 institutions were selected from the three categories of methyldopa use (low, moderate and high) for the prescription survey. The sample included hospitals from different regions within the province, both urban and rural. • 100 consecutive original prescriptions presented to the outpatient department for the management of uncomplicated essential hypertension were used to record the names and doses of the antihypertensives prescribed. Prescriptions for patients with co-morbidities were not included in the survey. • The prescriptions were analysed to determine the proportion of each antihypertensive class, proportion of prescriptions for monotherapy and combination therapy, the doses of antihypertensives prescribed and whether there were any significant differencesbetween the results of the supply data and prescription data. Figure 3: Proportion of monotherapy / combination therapy at hospitals in Kwazulu Natal Province. Comparison of the two methods Background and Setting • In 1998 the National Department of Health (NDOH) published standard treatment guidelines (STG) for the management of common medical conditions (including hypertension) at all public health facilities in South Africa. These treatment guidelines were designed to assist prescribers in making appropriate health care decisions in specific clinical circumstances. The guidelines were distributed through each of the provincial health departments to prescribers in the province. • It is unclear exactly what impact the guidelines have had on prescribers considering that the passive distribution of clinical guidelines has limited effect on changing prescriber behaviour. • Two previous surveys (at institutional level) of antihypertensive prescribing reported that prescribers are non-compliant with the STG for hypertension. Methyldopa was reported to be prescribed to 33% of the hypertensive patients. Results: Drug Supply Data Figure 1: Proportion of antihypertensives supplied to hospitals over a six month period Conclusion The supply data suggest that diuretics (hydrochlorothiazide) and ACEI are the first choice agents followed by methyldopa, reserpine, beta blockers and calcium channel blockers. Supply data are not an accurate reflection of use, particularly for drugs with multiple indications such as ACEI. Nevertheless, the drug use patterns were a useful indicator that informed the selection of hospitals for the prescription survey. The prescription survey is a more accurate measure of prescribing patterns. The survey of hypertension prescriptions suggests a similar trend (following the recommended stepped care approach) of first line diuretics (mainly hydrochlorothiazide), followed by angiotensin converting enzyme inhibitors (perindopril), calcium channel blockers, beta blockers, methyldopa, reserpine and hydrallazine. Study Aims • To identify the relative use of various antihypertensive drugs at the 63 provincial hospitals using supply data. • To supplement the supply data findings through a survey of patient prescriptions at 16 hospitals in the province. • To determine whether supply data is a useful indicator of drug use. • To determine whether there are any similarities between the prescribing of antihypertensive drugs and the recommendations of the treatment guidelines. Methyldopa Supply to Hospitals Methods • Two methods of assessing drug utilisation were used: • a drug supply database for 63 hospitals in KZN province • a prescription audit of a sample of these hospitals. Figure 2: Number of hospitals in each category of methyldopa supply Acknowledgements T Pillay was supported by an AusAID fellowship. WHO Collaborating Centre for Training in Pharmacoeconomics and Rational Pharmacotherapy