In all measured indicators the numerator is the debt service annual amount in current US dollars. Its exact "official" definition runs as follows:
Total debt service is the sum of principal repayments and interest actually paid in foreign currency, goods, or services on long-term debt, interest paid on short-term debt, and repayments (repurchases and charges) to the IMF. Data are in current U.S. dollars.
Source : World Bank, Global Development Finance.
The debt service / healthcare budget refers to the ratio between the debt service annual amount in current US dollars and the country’s total healthcare budget during the same year. Health budget is defined as follows:
Health budget, total (% of GDP) is the sum of public and private health budgets. It covers the provision of health services (preventive and curative), family planning activities, nutrition activities, and emergency aid designated for health but does not include provision of water and sanitation. (Source : World Health Organization, World Health Report and subsequent updates, and from the OECD for its member countries, supplemented by World Bank poverty assessments and country and sector studies.)
DS/HB = Total debt service (current USD) / [(Health expenditure (% of GDP) / 100) • GDP (current USD)]
A ratio DS/HB = 0,457 means that the debt service represents 45,7% of the healthcare budget. A ratio DS/HB = 3,487 means that the expenses due to debt service is 3,487 times more important than the healthcare budget.
Mode of interpretation: DS/HB meesures the burden of the debt service in relation to the country’s expenditure in healthcare. It shows to what extent debt service can prevent health expenditure.