Investigation into the prescribing patterns and cost of antidiabetic medicine in South Africa

Abstract

The general objective of this study was to investigate the prescribing patterns and cost of antidiabetic medicine in the private health care sector in South Africa by using a medicine claims database. A quantitative, retrospective drug utilisation study was performed on data for the year 2004. Oral antidiabetic medicine accounted for 81% (n = 143 447) and 39% (R29 734 360.61) respectively of the total prevalence and cost of all antidiabetic products prescribed. Metformin was the most frequently prescribed oral antidiabetic medicine, with an average cost of R58.42 (SD = 31.78). The three most frequently prescribed classes of insulin (insulin lispro; soluble insulin and isophane; and soluble insulin aspartame and protamine) together accounted for 63% of all the insulin prescribed, and 67% of the total cost of prescribed insulin. Almost 39% (n = 62 717) of the 'combination therapy' prescriptions were for a sulfonylurea in combination with a biguanide plus at least one otherantidiabetic product. A trend towards combination therapy away from monotherapy was observed. Prescribed Daily Doses (PDDs) calculated for oral antidiabetic medicines were more or less in line with recommended treatment guidelines. Drug utilisation review studies thus provide valuable insight into the treatment of diabetes - indicating areas of possible over- and under usage, providing decision-makers with critical information to curb unnecessary costs.