Study area, design, and period

The study was conducted in health facilities operating in central Ethiopia where 15% of the country’s population lives [19]. The study area encompassed Addis Ababa City Administration, which is geographically located in the central part of Ethiopia as the center, and five zonal capitals that border it, namely Adama (East Shewa Zone), Ambo (West Shewa Zone), Fiche (North Shewa Zone) and Waliso (Southwest Shewa Zone) located in the Oromia Region and Debre Birhan (North Shewa Zone) located in the Amhara Region. An institution-based cross-sectional survey was utilized to collect data regarding availability, affordability, and pricing of EMs. Estimates were prepared through collecting and analyzing data using the WHO/Health Action International (WHO/HAI) format from January 1, 2022, to February 28, 2022 [20].

Study facilities selection

The study area has six administrative districts. Considering Addis Ababa, the capital city of Ethiopia, as a center for the study, five districts that can be reached within 1 day, have public health facilities (PHFs) that have provided diabetes care services for at least one year, handle selected EMs for diabetes care, and have pharmacy professionals and physicians to manage the interest of patients with NCDs were selected. According to the standardized WHO/HAI methodology, hospitals and health centers’ outpatient pharmacies from the public sector, and retail pharmacies and drug stores from the private sector (in the same areas as the selected public health facilities) were identified and used as study settings [20].

Medicine outlets selection

The country’s three-tier system (primary, secondary, and tertiary level categorization of HFs) of healthcare served as a baseline for selecting medicine outlets [21]. Purposively taking one main hospital from the higher level of the framework for each selected study area, the remaining PHFs (2 public hospitals and 2 health centers (HCs)) within three hours of travel from it were randomly selected from the lists of PHFs obtained from the health bureaus of Addis Ababa, Oromia, and Amhara regions for the public sector [20]. Five licensed and private medicine outlets (PMOs) which were proximate to selected PHFs in each study area were also chosen by simple random sampling. In total, 60 medicine outlets were included, 30 from the public and 30 from the private sector.

Study medicines selection

Thirty-five EMs were identified and selected based on the (i) 2019 WHO 21st list of EMs for adults [12], (ii) medicines commonly used for treatment of DM and medicines for CV risk management that are listed in the current (6th edition) Ethiopian Essential Medicine List (EML) [22] published in 2020 and additional products based on expert opinion. Two forms of products were selected and surveyed for each medicine; namely, the originated brand (OB), more specifically the brand-name proprietary product, and the lowest-priced generic (LPG) product, the cheapest generic equivalent that was present at each pharmacy during the time of the survey [20].

Data collection and analysis

Data collection was adapted from the WHO/HAI’s standardized methodology on measuring medicines availability, prices, and affordability [20]. Three experienced pharmacists were appointed and trained as data collectors for this study. They received one-day training on the study’s purpose, the different names, strengths, and dosage forms of selected medicines, how to complete the data collection form, and how to compute unit costs. Data on the availability of EMs was determined by direct observation: a medicine was considered available if it was on the shelf and ready to be dispensed at the time of the visit. Price data (selling prices of medicines for end users) was recorded for medicines in stock. Public-sector procurement prices were gathered from Ethiopia’s public procurement agency, i.e., Ethiopian Pharmaceutical Supply Services during the previous two years.

For tracking quality of data collection, processing, and statistical analysis, data were entered into a customized MS Excel from the workbook provided as part of the WHO/HAI methodology. All medicine outlets surveyed fulfilled the WHO/HAI recommendation criteria to collect data on the selected 35 medicines (Table 1) [20].

Table 1 Availability of diabetes care essential medicines (EMs) in the central EthiopiaDefinitions of availability, price, and affordability of medicines

The availability of each studied EM was measured by its physical presence in the medicine outlets by their specified strength and dosage form on the survey date. It was determined as the mean percentage (%) availability of individual medicines, availability across groups of medicines, variations between product types such as (LPG vs OBs), and of individual medicines between sectors [23,24,25]. The current study utilized percentage ranges: 0%—absent— not found in any retail outlet surveyed; < 30%—very low— very difficult to find; 30%-40%—low— somewhat difficult to find; 50%-80% fairly high— available in some retail outlet; and > 80% very high— good availability to describe the extent of availability of medicine for diabetes care [23, 24].

Prices for products were taken as unit prices and defined as price per capsule or tablet or vial (least measurable unit). It was computed using the following equation.

Both price lists and prices on the pack of medicine were used to fill in the data for each surveyed medicine physically found in each sampled facility. The prices were converted to US dollars using the buying exchange rate, i.e., 1 USD = 49.1482 Ethiopian Birr (ETB) which was taken from the Ethiopian National Bank website on January 1st, 2022, the first day of data collection [26]. In the analysis of price data, both LPG and OB medicines were analyzed separately. The median value of retail price, interquartile price ranges, and minimum and maximum prices were used to describe individual medicine prices in local currency (ETB). Price data of medicines that were found in less than four medicine retail outlets were not included in the price analysis, given the small sample size and low precision of potential estimates.

Affordability was estimated by comparing the total cost required to cover one-month course of therapy based on the lowest-paid government worker's (LPGW) daily wage [20]. Assessment of affordability for standard treatment of each medicine used the defined daily dose (DDD) of each EM, which is the “assumed average maintenance dose per day for a drug used for its main indication in adults” and serves as a standard dose unit of measurement [27]. Accordingly, affordability was calculated by applying the following equation.

$$Treatment\;course\;cost=Number\;of\;unit\;dose\;required\;for\;DDD\;of\;EM\;x\;Median\;Unit\;price\;of\;EM\;x\;Days\;of\;a\;treatment\;course$$

If the cost of a course of treatment of an anti-diabetic medicine is no more than one day’s wage or income, it is considered affordable. The treatment courses that cost more than one day’s wage were classified as unaffordable. Thus, daily wages were used to express affordability and calculated by dividing the cost of the treatment course by the LPGW’s daily wage. As of January 2022, the Ethiopian Civil Service Authority paid 1409 birr per month or 28.67 USD per month to the LPGW. As a result, the daily wage was calculated by dividing the monthly salary for the previous 30 days, which was ETB 46.97 per day (USD 0.96 per day).