Cost variation analysis of commonly prescribed anti-diabetic drugs available in Indian market: a pharmaco-economic study

INTRODUCTION

DM is a chronic metabolic disorder requiring lifelong treatment.¹ Due to rapid urbanization, unhealthy diet habits and a sedentary lifestyle, the incidence of DM is increasing.² The global DM prevalence in 2019 was estimated to be 9.3% (463 million people) and is expected to rise to 10.2% (578 million) by 2030 and 10.9% (700 million) by 2045.³ In India too, DM is fast gaining the status of a potential epidemic with nearly 65 million diabetic individuals currently diagnosed with the disease.⁴

The chronic nature of DM causes significant personal suffering and economic difficulties to families.⁵ Since patients with chronic illnesses often take multiple medications, they are particularly susceptible to medication cost pressures. Patients who are concerned about out-of-pocket medication costs often restrict their use of prescription drugs.⁶

Indian market is predominantly a branded generic market, more than one company sells a particular drug under different brand names apart from the innovator company. Hence, the number of pharmaceutical products available in the market is very high in the range of 60,000-70,000 products. This situation has led to greater price variation among drugs marketed.⁷ Studies suggested that the prescribing doctors have a poor knowledge of cost of drugs. Much more focus is required in the education of physicians about costs and the access to cost information so that they can choose the least costly medication when there are no substantial differences in safety and efficacy between the least and most expensive.⁸

Increasing pharmaceutical costs negatively impacts patients in two ways. First, high direct expenses for those of limited resources may mean a choice between medicines and necessities such as food or clothing. Alternatively, patients who do not take their medicine as directed or go without the potentially beneficial therapies suffer negative health consequences.^9,10 Patients may also sometimes be too embarrassed to tell their physicians when they cannot afford their medicines.⁶

The aim of our study was to analyse cost variation of commonly prescribed oral anti-diabetic drugs which were available in the Indian market under various brand names. In addition, we have also compared their cost-ratio and percentage cost variation alongwith their maximum and minimum price.

METHODS

A cross-sectional, observational study was carried out at a tertiary hospital in Western India over 2 months from 1 May 2021 to 31 June 2021 after approval from the institutional ethics committee. The study adhered to the tenets of Declaration of Helsinki. Price in INR of commonly used oral anti-diabetic drugs of same preparation and same strength manufactured by different pharmaceutical companies was obtained from CIMS website, IDR 2021 issue and National pharmaceutical pricing authority-pharma sahi daam . The cost of 10 tablets (pack size) was calculated. The minimum and the maximum cost in INR of a particular anti-diabetic drug manufactured by various pharmaceutical companies of the same strength was noted. The cost ratio defined as the ratio of the costliest brand to that of the cheapest brand of the same drug was calculated as follows,¹¹

Percentage cost variation was calculated as follows,¹²

From the above two ratios, we assessed how many times more does the costliest brand cost, compared to the cheapest brand. All detailed data was entered in MS excel and values expressed in counts, percentages and ratios.

RESULTS

The cost of 23 commonly used oral anti-diabetic drugs (15 single and 8 combination preparations) manufactured by different pharmaceutical companies were analysed.

Single drug preparations

Among single drug preparations, a total 15 commonly used preparations were analysed (Table 1). The highest percentage cost variation was found for metformin 500 mg sustained release (3668%). Other significance high cost variations were glimepiride 1 mg (3503%), gimipiride 2 mg (2520%), glipizide 5 mg (1960%), glibenclamide 5 mg (1779%) and metformin 500 mg (1718%). The minimum cost variation was found with glipizide 2.5 mg (65%) followed by gliclazide 60 mg (71%), sitagliptin 100 mg (77%), gliclazide 30 mg (84%) and acarbose 25 mg (86%).

Maximum number of brands is available for glimepiride 1 mg and 2 mg (108 brands each) followed by teneligliptin 20 mg (118 brands), voglibose 0.2 mg and 0.3 mg (101 brands). Minimum number of brands were available for linagliptin 5 mg (2 brands) followed by sitagliptin 50 mg and nateglinide 60 mg (3 brands each). The most expensive was sitagliptin 100 mg (₹ 450) followed by sitagliptin 50 mg (₹ 414) and metformin 500 mg SR (₹ 280). Minimum cost was of glipizide 5 mg (₹ 1.43) followed by glipizide 2.5 mg (₹ 2.52) and gliclazide 5 mg (₹ 2.66).

Fixed dose combinations

Amongst fixed dose combinations, a total of 8 commonly used combination preparations were analyzed (Table 2). The maximum cost variation was found for glimepiride 2 mg+metformin 1000 mg (2703%). Other significant high cost variations were glipizide 5 mg+metformin 500 mg (1991%), gliclazide 80 mg+metformin 500 mg (1758%), glimepiride 2 mg+metformin 500 mg (1527%) and glimepiride 2 mg+metformin 500 mg SR (1163%). While minimum cost variation was found in repaglinide 1 mg+voglibose 0.3 mg (26%) followed by repaglinide 1 mg+voglibose 0.2 mg (29%), glimepiride 2 mg+metformin 500 mg+pioglitazone 30 mg (36%), voglibose 0.3 mg+metformin 500 mg+glimepiride 1 mg (137%) and voglibose 0.3 mg+metformin 500 mg+glimepiride 2 mg (225%).

Maximum number of brands were available for glimepiride 1 mg+metformin 500 mg (168 brands) followed by glimepiride 2 mg+metformin 500 mg+pioglitazone 15 mg and voglibose 0.2 mg+metformin 500 mg+glimepiride 2 mg (101 brands each). Minimum number of brands were available for glimepiride 2 mg+metformin 500 mg+pioglitazone 30 mg (3 brands) followed by repaglinide 1 mg+voglibose 0.2 mg (4 brands). Maximum price was of gliclazide 80 mg+metformin 500 mg (₹ 500) followed by voglibose 0.3 mg+metformin 500 mg (₹ 318) and voglibose 0.3 mg+metformin 500 mg+glimepiride 2 mg (₹ 260). Minimum cost was of glipizide 5 mg+metformin 500 mg (₹ 6.72) followed by glimepiride 1 mg+metformin 500 mg (₹ 9) and glimepiride 2 mg+metformin 500 mg (₹ 10.77).

DISCUSSION

In the present study, a noticeable cost variation was found in different brands of the same oral antidiabetic drug. The most commonly prescribed single drug therapy was metformin 500 mg SR.¹³ It showed the maximum price variation of 3668%. This was unlike the study by Dharani et al and Mehani et al wherein the maximum cost variation was seen with glimepiride 2 mg and 1 mg respectively.^14,15 The highest cost variation among multiple drug therapy was seen with the combination glimepiride 2 mg+metformin 1000 mg (2703%) unlike the study by Dharani et al and Mehani et al in which maximum cost variation was seen with glimepiride 1 mg+metformin 500 mg.^14,15

Drug prices in the Indian market are controlled by the NPPA of the Government of India. It fixes the ceiling price of a particular drug based on its essentiality. This prevents pharmaceutical companies from selling medicines from the drugs prices control order (DPCO) list at a price which is higher than the fixed price.¹⁶ Amongst various oral anti-diabetic drugs, only two drugs namely glimepiride and metformin are under DPCO price control (Table 3). Other newer agents frequently prescribed by the treating physician, either alone or in combination, are not under price control. Wealth is not distributed equally. So, the gap between the rich and poor continues to widen in India.¹⁷ The poor and middle classes cannot afford high quality health care like the wealthy.¹⁸ Hence, prescribing doctors should strongly consider drug prices especially in a developing country like India, where a majority patients are paying out of their pockets for their medical expenses and are not covered by insurance schemes.⁸ In India, more than 80% health financing is borne by patients. If an expensive brand is prescribed, patients have to unnecessarily pay more for the same medicine which in turn increases the economic burden on them.⁸ This can be prevented by educating the masses about various health insurance facilities available, so that good quality and affordable healthcare can be given to them.

Being a chronic disease, the management of DM requires continuous medical care. Prescribing doctors may not necessarily know the cost of the drugs. Some clinicians also get lured by various incentives provided by the pharmaceutical companies and thus prescribe more expensive drugs when a cheaper alternative is available. Rational use of drugs is defined as patients receiving medications appropriate to their clinical needs, in doses that meet their own individual requirements, for an adequate period of time and at the lowest possible cost.¹⁷ Many brands of a particular drug available for an indication makes the decision complex and less rational. Thus the physician’s P drug list should consist of selected safe, efficacious and cost-effective drugs to ensure their rational use.

CONCLUSION

The present study shows that there is a wide variation in the cost of different brands of the same oral anti-diabetic drug currently available in Indian market. Pharmaco-economics should be given greater emphasis during medical training. Physicians should switch to cost effective therapy and prescribe rationally. Education about health insurance facility should be given to all people. More oral anti-diabetic drugs should be covered under DPCO so that all patients irrespective of their financial condition will be able to afford these medicines. In case of non-compliance to DPCO by pharmaceutical companies, more stringent actions should be ensured.

Funding: No funding sources

Conflict of interest: None declared

Ethical approval: The study was approved by the Institutional Ethics Committee

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