The Direct Cost and Pattern of Anti-Diabetic Therapy among Patients in a Teaching Hospital in a Resource-Poor Setting

Introduction

Diabetes mellitus (DM), a prevalent and chronic metabolic disease, is one of the most significant challenges healthcare systems face globally, especially in Nigeria, where the standard of living and quality of life are low [1]. All age groups are impacted, with a male preponderance, and the majority over 65. Type 2 DM, due to insulin resistance or insufficient production, is commoner [2]. Globally, an estimated 537 million persons aged 20-79 years, accounting for approximately one in ten individuals, are affected by DM, with this figure expected to rise to about 783 million by 2045 [3]. The disease was said to have contributed to 6.7 million deaths in 2021 alone [3].

Diabetes Mellitus causes a significant burden on society vis-à-vis increased frequent hospital visitations, medical care costs, premature death, productivity losses, and reduced quality of life [2, 4]. The illness imposes significant financial burdens on the patient, their families, and the public healthcare system because it is a lifelong condition with severe, disabling effects [1, 5]. The patients’ direct medical cost is linked with money expended on consultation, investigations and treatment within the health system [6].

The management of DM depends on its severity and duration to lower the risks of complications, which, according to the American Diabetes Association (ADA) and the European Society of Cardiology (ESC) guidelines widely used for the management of DM [7]. Physical exercise and dietary modifications are the first line of treatment, before considering drugs when there are poorly regulated glucose levels in the blood [7, 8, 9]. These drugs, including insulin, also have different mechanisms of action to maintain and optimize glycemic control [7, 10]. Individuals on anti- diabetic drugs are also placed on it for life, which, in a sense, could be either cumulatively or singly expensive. Due to the chronicity of the illness, a substantial financial liability is imposed on households on treatment costs managing this ailment [11]. There is a paucity of studies within the geographical region in which the study assessed treatment costs and the prescribing pattern of anti-diabetic agents due to the availability of newer drugs for treatment in the market. Based on this background, the study examined the abovementioned objectives among out-patients attending an endocrine clinic in a tertiary health facility in South-Southern Nigeria.

Materials and Methods

A cross-sectional design was adopted for the study. A prevalence-based, ‘cost-of-illness’ study (a descriptive economic evaluation method) using the micro-cost estimation method was used to calculate the direct cost of diabetic care medications.

Results

Respondents who attended the DM clinic ranged from 18 to 93 years, with a mean age of 53.22 ± 13.07 years. Most

respondents (39.4%) were in the 50-59 age group, with males (54.8%) being the predominant gender. Most respondents were Christians (97.1%) and married (86.5%). More than half (56.7%) had completed tertiary education. About one- fifth (21.2%) of the respondents were civil servants, and all (100%) respondents paid out-of-pocket (Table 1).

^Others (retirees, pensioners, housewives, self-employed) Table 1: Socio-demographic characteristics of respondents.

About half (48.1%) of the respondents were diagnosed more than five years ago. Most (58.7%) were hypertensive; only one respondent had degenerative spine disease, while two-fifths (40.4%) did not have co-morbidities. All respondents (100.0%) visited the follow-up clinic once a month (Table 2).

The monthly costs of mixtard and glargine insulin were ₦374, 967/ $858.34 and ₦323, 451/ $740.41, respectively, among respondents, while the average costs of the former and latter were ₦74, 993.40/ $171.66 and ₦14, 063.08/ $32.19 monthly, respectively. Metformin, vildagliptine, and glibenclamide average costs were ₦2, 779.43/ $6.36, ₦13, 921.87/ $31. 86 and ₦613.63/ $1.40 monthly, respectively. The majority 23 (82.1%) of respondents on injectable were on glargine insulin, while a higher proportion, 71 (68.3%) of those on oral hypoglycemic agents, were on metformin, closely followed by glimepiride 34 (32.7%). The least of the respondents were on glibenclamide 11 (10.6%). The overall cost of hypoglycemic agents was ₦1, 576, 458.00/ $3, 608.69 (Table 3).

Most respondents used metformin 71 (68.3%) compared with other drugs, while the least prescribed medication was pregabalin and gabapentin 19 (18.3%). Slightly less than one-third, 32 (30.8%) of respondents were prescribed galvusmet, a combination of metformin and vildagliptin, and the average cost of this drug was (N13, 921.87/ $31.86). Of the prescribed medications, the average cost of daonil was N613.63/ $1.40, the least commonly prescribed (Table 3).

*OHA: Oral Hypoglycaemic Agents | #Others include Gabapentin and Pregabalin | *Most patients were on polytherapy (insulin and OHA) | ^combined mean of medications. Table 3: Drug costs for disease management incurred by DM patients monthly in DELSUTH, Oghara.

Discussion

Diabetes Mellitus is regarded as a debilitating non- communicable disease that exposes households to financial hardship and worsens their economic fortunes due to rising care costs. This study’s preponderance of respondents was above 50 years, which is expected given that the epidemiology of type 2 DM commonly develops in the latter part of life and usually affects individuals in their fifth and sixth decades of life, as studies have shown [12, 13, 14]. Studies conducted in tertiary health facilities in Umuahia, Yenogoa, and Ghana reported similar findings regarding the predominant age group accessing care [1, 15, 16]. Nevertheless, in contrast to the results of this study, a higher disease burden was reported among individuals within the 36-44-year age group in referral facilities in Ethiopia and Thailand [17, 18]. This variance amongst the study populations in our study and the latter could be attributed to these respondents having better self-awareness, health-seeking behaviours and presenting earlier at the health facilities than respondents in the current study. The onset of DM and its associated complications can be considerably delayed with early identification of at-risk persons and the immediate adoption of appropriate interventions, such as intentional weight loss, increasing physical activity, and improving medication adherence.

Fifty-seven males (54.8%) had a higher proportion of diabetes, as reported in our study. This is in support of other reports which have been documented elsewhere [1, 14]. Men tend to store more of their fat in the abdomen as visceral fat than women, and this fat storage over time is typically linked to insulin resistance, leading to glucose intolerance and type 2 DM, which may explain this observation. On the other hand, women have more subcutaneous and peripheral fat storage, which correlates with insulin sensitivity and protection against type 2 DM. Women, nonetheless, have been reported in other studies to be a majority suffering from DM, which is inconsistent with the report of this study and may have been due to clinico-demographic and study design variants [13, 19, 20].

Respondents in this study with hypertension (58.7%) were predominant among those with other intercurrent disorders, although less than reported in a study in Ghana (63.7%) and in Ogbomosho (60.5%) [13, 21]. This is plausible as hypertension is a well-known co-morbidity with the development of DM and vice-versa. This result implies that apart from monies spent on anti-diabetic medications, more household earnings will be expended on drugs, reducing spending on other basic needs at home.

Our study found drug costs in managing DM to be high and consistent with other study findings among their study population [13]. The reason for this is unclear but may be related to the high cost of brands of drugs being prescribed by the clinician due to effectiveness and the need to optimize the glycemic levels of their respective patients. Another reason may be that the cheaper ones like Daonil, which had a total cost of ₦6, 750/ $15.45 and an average cost of ₦613.63/ $1.40 among the eleven patients being treated for DM, may not be well tolerated by the entire population of interest. It is also well-established that Daonil results in rapid hypoglycemia, hence the caution with use in most patients.

The prescription pattern revealed metformin (biguanides) as monotherapy or combination therapy frequently prescribed in almost 7 in 10 respondents. This was followed by glimepiride (sulfonylurea) (32.6%). Reasons may not be unrelated to the fact that the drug is considered the drug of choice for initial treatment of type 2 DM, to being preferable or better tolerated by patients, the patient’s clinical characteristics, or the duration of treatment. This study’s finding is consistent with prior studies which reported a similar result of metformin being the most frequently prescribed drug at the endocrine clinics [7, 22, 23, 24, 25]. Only more than one-fourth (26.9%) of respondents were placed on insulin as stand-alone or supportive therapy in this study, slightly lower than that recorded in another study (27.7%) [26]. This is possible, considering the patients were treated for type 2 DM, not type 1 DM, which depends entirely on insulin. However, Uwakwe, et al. [14] reported an even lower prevalence (13.3%) among a similar population of interest in a tertiary facility in Jos, Nigeria [14].

All one hundred and four respondents (100.0%) paid out-of-pocket to purchase their medication, which is alarming, bearing in mind the high total and average costs of hypoglycemic agents documented for this study. This finding demonstrates that there were no forms of health insurance to cushion this unfair access to diabetic care. An explanation may be that respondents failed to avail themselves of the opportunity to register for the state’s health insurance program, which is well-advocated and advertised in the entire state. Developing countries are also known for not implementing health insurance for the citizenry compared to developed countries [27, 28, 29]. To corroborate our study findings, all patients on diabetic treatment in other studies in Nigeria similarly paid out-of-pocket to access care [15, 20, 30]. This form of payment, in the long run, predisposes such an individual and, by extension, the household to catastrophic expenditure where crucial needs of the family such as food, shelter and clothing will not be met.

Conclusion

The overarching goal of DM management is to prevent target organ damage and other attendant problems by achieving optimal glycemic control with the rational prescription of hypoglycemic medications. This study has demonstrated the high cost of treatment of diabetes and has shown that metformin was the frequently prescribed drug. This study provides evidence for policy guidelines towards implementing community-based health insurance programmes, which cannot be overemphasized to enable the underserved to access diabetic care.

Contribution of Authors

OOA, PGO – were involved in the conceptualization of the study OOA- wrote the proposal, participated in the data collection process, data analysis and drafted the manuscript MIN, FTA, OA- drafted the manuscript All authors read and approved the manuscript