SAH costs

The costs of SAH includes the services provided by the three healthcare levels (primary, secondary, and tertiary). Primary care was included because the main SUS strategies for prevention, diagnosis and control of SAH occur at this level [42].

The costs of SAH in secondary and tertiary care were obtained from the Outpatient Information System (SIA/SUS) and Hospital Information System (SIH/SUS). Both systems are national and provide the values reimbursed by the Ministry of Health of Brazil to the health services that performed the medium- and high-complexity procedures, including medical consultations, NPHW care, drugs administered at health units, hospitalizations, surgeries, support care, complementary procedures and laboratory and imaging exams. The data were extracted using the 10^th version of the International Classification of Diseases (ICD-10) in terms of SAH (I10). The data were analyzed using TabWin software, created by the Ministry of Health of Brazil [43].

The costs of SAH in primary care include expenses on medical and NPHW consultations and antihypertensive drugs. The number of medical and NPHW consultations for SAH was obtained from the Health Information System for Primary Care (SISAB/SUS) [44]. A value of Int$ 4.54 was used for medical consultations and Int$ 2.86 for NPHW consultations; Int$ 1.43 was added for home visits [45].

There is no public national registry of the number of drugs dispensed to hypertensive patients in primary care. Thus, our estimate was based on epidemiological data and public access to the National Survey on Access, Use and Promotion of Rational Use of Medicines (PNAUM) [15,46]. For each drug, the daily defined dose (DDD) [47] was multiplied by 365 days in order to obtain annual intake. The cost per pharmaceutical unit was obtained from i) the Health Prices Database (BPS) [48] for drugs dispensed in public pharmacies (hydrochlorothiazide, losartan, captopril, enalapril, atenolol, amlodipine, propranolol, furosemide and nifedipine), accessed on 07/24/2020, and ii) the reference price for drugs dispensed in private pharmacies of the PFPB (hydrochlorothiazide, losartan, captopril, enalapril, atenolol and propranolol) [49]. The BPS is a mandatory registry system that allows public access to government purchases of drugs and other health-related products in Brazil. The weighted average of the price of each drug was obtained from this database, the weight factor being the number of drugs acquired up to 07/24/2020. Since the drugs amlodipine, furosemide, and nifedipine are not available in PFPB, the prices charged at public pharmacies were used. The number of hypertensive individuals under drug treatment was obtained from the literature [15]. The distribution of antihypertensive drugs in use by the population in the SUS was calculated based on the primary data of the PNAUM [46]. We considered the cases in which patients used up to three drugs concomitantly. Thus, the distribution was as follows: 54.7% of hypertensive patients under drug treatment used only one; 37.4% two and 7.9% three antihypertensive drugs. Based on the same study [46], it was also possible to identify the distribution of each drug used by hypertensive patients, stratified by the number (1, 2 or 3 drugs). The complete description of the parameters used in the analysis can be found in S1–S4 Tables.