This study was conducted from Bomet county located in the south rift valley region of Kenya and occupies an area of 1,630 km2. It is comprised of five constituencies (Bomet East, Chepalungu, Bomet Central, Konoin and Sotik), with a combined estimated population of 891,390 inhabitants and a fertility rate of 4.3 [15]. Rate of skilled birth attendance was 52.2% in 2014 [15]. The total number of 145 health facilities consists of one public referral hospital (Longisa county referral hospital, LCRH), two faith-based hospitals, five sub-county hospitals, 23 health centers and 114 dispensaries. All public health services are financed by the county government of Bomet. In LCRH, services include comprehensive emergency obstetric and newborn care (CEmONC) and 24-hour ambulance services free-of-charge to transfer women from their villages or health centers in case of obstetric complications. The faith-based and sub-county hospitals also provide CEmONC services and have access to the same ambulance services. The county government of Bomet owns two ambulances and hires four from Kenya Red Cross Society; three of the hired ambulances are located in in LCRH of which are our economic evaluation assessment was based. Each ambulance operates independently, covering distances between LCRH and health centers ranging from 2 to 48 km.
This was a facility-based cross-sectional study involving a retrospective chart review among women who had been admitted with obstetric complications brought in either by ambulance or as self-referrals between January, 1st, to June, 30th, 2019 in LCRH, Bomet, Kenya. Eligibility for the study was independent of gestational age: all women who arrived in LCRH with pregnancy related complications were included. Women who developed complications more than 42 days after termination of pregnancy were excluded. Every woman admitted with a pregnancy related complication was assessed using the adapted sub-Saharan African Maternal Near Miss (MNM) criteria [16]. Each referred woman was categorized as: ‘necessary referrals’ meaning that they were managed for either MNM or potentially life-threatening complications (PLTC) and ‘unnecessary referrals’ meaning those with no obstetric complications. A necessary referral was assumed to be a woman referred from a lower to a higher level of care, meaning LCRH, where either MNM or PLTC cases were supposed to be managed. An unnecessary referral was assumed to be a woman without obstetric complications who should have received care at lower levels of care including health centers. Additional data included transport costs, clinical care costs and accessibility to LCRH in terms of distance and modes of referral. These were retrieved from obstetric records, ambulance call logbooks, referral registers, perinatal registers and financial records.
Mode of referral was grouped into ambulance transfer and self-referral. Ambulance transfer was a woman brought by ambulance and escorted by health care professionals to LCRH. Self-referral was a woman who arrived in LCRH by other modes of transport such as private car, motorcycle or by foot directly from home. Associated conditions are diseases or conditions that may be relevant to a severe maternal outcome but are not part of the chain of events leading to that severe maternal outcome. Our hypothesis was an increased number of ambulance transfers among women managed for either MNM or PLTC as compared to women without obstetric complications at onset of referral who would opt to use other modes of transport.
Costing analysis was performed from the health care provider’s perspective, being the county government of Bomet [17]. All costs falling under the county health system were included. These included ambulance and health services provided in LCRH. Our study did not take into consideration opportunity costs when accessing health care. These included costs incurred by patients and families, resources used by health care providers from referring agents and other parties like insurance companies and donors.
Recurrent costs included drivers’ and paramedics’ salaries, allowances for accompanying drivers and paramedics on night/weekend calls, length of hospital stay, laboratory tests, radiology procedures, clinical care costs incurred during vaginal birth, surgical interventions such as cesarean section or laparotomy and management of other obstetric complications. Recurrent costs also included ambulance fuel/insurance/maintenance, electricity, water bills, and cell-phone communication. We computed transport costs incurred among self-referrals using Geo-measure area calculator to estimate distance from home or private clinic to reach LCRH, multiplied by costs of fuel per kilometer. We also assumed that women had been accompanied by one person implying transport doubled the costs incurred per woman. Fuel costs for non-obstetric cases were excluded. Costs were calculated based on the National Health Insurance Fund delivery costs [14]. Data on quantities and costs of recurrent and capital overhead goods were obtained as recommended [17]. Overheads were calculated using the allocated shared costs based on time and units of consumption of each shared input [18]. Capital items were physically enumerated and the actual amount of recurrent items was obtained by reviewing general store records, pharmacy, purchase records, hospital’s supplies, accounts and Kenya medical supplies agency records. All costs were presented in Kenya Shillings (KES) and converted into US dollars (1 US$ = 103 KES). The cost of capital resources such as ambulances appeared as a single large amount at the beginning of an evaluation period. We computed the equivalent annual costs based on WHO regional recommendations through annualizing capital costs [17]. The costs in each cost center were added to obtain total costs. These were divided by the interventions output to provide the unit cost of delivering costs for necessary ambulance transfers and self-referrals. The unit cost per inpatient per day was obtained by dividing total inpatient costs (capital and recurrent costs) by the total number of admission days for women with necessary referral.
Ambulance or self-referral benefits were presented as cost per life years gained (LYG) for every referral of women categorized as necessary referrals based on local life-expectancy tables. This was adopted from the WHO reported 66 years as female life expectancy in Kenya. To calculate life expectancy related to different ages of women, we used the table for “the expectation of life at age” [19]. The table does report the average life expectancy for each age; clustered in age groups each containing four years, from 1 to 4, 5 to 9, 10 to 14, until 100+. The older the woman becomes the lower her life expectancy, the lower the life years gained when ambulance referral or self-referral were ‘necessary referrals’. The formula to calculate LYG was as follows: LYG for every MNM or PLTC case categorized as necessary referral was 66 (average life expectancy) minus the expectation of life at the age of the mother (as indicated in the expectation of life for age table). For every categorized case as necessary referral, the same formula was adopted. Therefore, total LYG was the sum of all life years gained for necessary referral cases. Finally, our results were derived from the formulas below:
Sensitivity analysis was performed using discount rates of 3% and 6%. First, we discounted costs and life years gained (LYG) by 3% for the proportion necessary referrals and later increased the discount of life years gained to 6%. Finally, incremental cost effectiveness ratios (ICER) for the referral intervention were considered acceptable, attractive, or very attractive interventions when costs per gained life years were below Kenya’s GDP per person of 1507.8 USD; attractive when < 150 USD and very attractive when < 30 USD [19].