Overview
This cost-consequence analysis assessed clinical and economic outcomes for CHX gel compared with DCC for neonatal umbilical cord care in Kenya, from both healthcare system and societal perspectives. Clinical outcomes were number of cases and number of cases avoided by sector. Economic outcomes were direct, indirect and total cost of care for omphalitis, resource use (number of bed days and outpatient visits) and societal impact (workdays lost). Breakeven analysis was performed to ascertain the price of CHX that would lead to a net-neutral budget outcome.
Model structure
The model is a spreadsheet calculation (Microsoft Excel) analysing the frequency of omphalitis cases and financial implications (cost-consequence) associated with implementing either DCC or CHX as cord care strategies in neonates (Figure 1). For each strategy, the number of cases of omphalitis is calculated, followed by the overall cost of the infection accounting for the sector providing omphalitis treatment (private, public, FBO) and the setting of care (inpatient or outpatient).
Model inputs
Key model inputs are summarised below; further details are provided in Supplementary Tables 1–6.
Patient population: Birth cohort of 500,000 in Kenya for 1 year, with an average birth weight of 3.3 kg [23].
Clinical efficacy: The inputs used to determine the clinical efficacy of DCC and CHX for the base case analysis were taken from a Cochrane systematic literature review based on three RCTs conducted in Asian countries [8-10, 24]. The Cochrane review provides the largest pool and most robust data for clinical efficacy and was used by the WHO to support its recommendation for use of CHX versus DCC [11, 24]. Additionally, two RCTs, conducted in African countries, were used to determine the most relevant and applicable efficacy inputs to be used [16, 17]. Further justification for the use of this literature is shown in Supplementary Table 7. Relative risk of omphalitis - due to limitations on data reporting within publications, an overall relative risk for omphalitis for CHX versus DCC could not be calculated, and for the base case was assumed to be equivalent to the relative risk reported in the Cochrane review for the “redness extending to the skin” categorisation (RR:0.73). This is a conservative effect size when compared with that reported for other severity categories [24]. Omphalitis case inputs - the inputs to determine the number of cases of omphalitis calculated in the model were taken from the efficacy of DCC and CHX from the Cochrane review comparing the two cord care approaches [24] (Supplementary Table 1). As an overall incidence rate of omphalitis was not reported in the Cochrane review, a weighted average was calculated of incidence rates of all severities of omphalitis associated with the DCC intervention arm from the three randomised control trials included in the Cochrane review [24].
Cord care treatment costs: The aim of the present analysis was to determine the breakeven budget-neutral price of CHX, therefore, the acquisition cost has not been included. As there is a generic local manufacturer in Kenya, it was assumed that all CHX was locally manufactured. For locally manufactured CHX, which is delivered in a multiple-application formulation, the number of days of treatment in each tube becoming wastage is also assumed. DCC was assumed to be associated with a zero cost. Cost inputs were converted from Kenyan shillings (KSH) to USD at an exchange rate of 100.83 KSH per 1 USD (Statistics, 2018) (Supplementary Table 2).
Proportion of patients per sector: No data could be identified in the literature; therefore, assumptions based on clinical opinion were used for the proportion of omphalitis cases treated in different sectors (Supplementary Table 1).
Inpatient and outpatient resource use and costs: The proportion of patients treated in each setting was based on clinical opinion. Costs for inpatient days and outpatient visits were populated drawing on the costs for Kenya provided in WHO-CHOICE 2008 [25], inflated to 2019 cost using the annual Kenya Consumer Price Index [26]. Costs accounted for personnel, capital and (for inpatient care) food [25, 26]. To reflect the structure of Kenya’s outpatient facilities, health centers (no beds), health centers (with beds) and primary level hospitals were averaged to provide an input for primary level care costs. Outpatient care was averaged across primary level, secondary level and teaching hospitals, weighted by the proportion of patients treated in each setting (Supplementary Table 2).
Medication costs: These model inputs were based on WHO guidelines, Kenya Paediatric guidelines and expert clinical opinion and assume the medication used and duration of treatment for omphalitis is influenced by sector and setting of care [4, 27] (Supplementary Tables 2 and 3). Costs were calculated using the cost of the medication by pack/vial, dosage prescribed and treatment length (in days).
Non-medication costs: Laboratory test costs associated with treating omphalitis were sourced from the literature [28], with FBO sector laboratory costs assumed to be one-third of private sector costs. To reflect the reality of the clinical environment, other non-medication costs were also included based on clinical opinion. This included the number and cost of consumables, and number of laboratory tests associated with treating omphalitis, both assumed to be equivalent across sectors (Supplementary Tables 4 and 5).
Societal factors and productivity: To understand the caregiver/family impact of caring for a child with omphalitis in Kenya, the model also estimated the impact on productivity and private financial losses based on the average gross salary and workdays lost through caring for a neonate with omphalitis. (Supplementary Table 6).
Model assumptions
Assumptions relating to incidence rates of omphalitis with DCC, comparative efficacy of CHX versus DCC, medication use and productivity loss are listed in Table 1. Further details on model assumptions are included in the Supplementary Methods.
Analysis
For the primary analysis a healthcare system perspective was taken to estimate the costs and benefits of implementing CHX for the Ministry of Health in Kenya or relevant healthcare provider, both overall and by sector (private, public or FBO) and setting of care (inpatient or outpatient). This included medication cost and costs associated with healthcare resource use in the treatment of omphalitis. In addition, a scenario with a societal perspective on the introduction of CHX was also analysed. This included the impact on productivity and workdays lost associated with time off work due to the consequences of different cord care interventions. The time horizon was 1 year, so no discounting was applied. Input values for the base case (direct costs only) and scenario (which also included indirect costs) are described above and in Supplementary Tables 1–6.
The analysis aimed to determine the impact on the costs of omphalitis treatment. Therefore, the cost of CHX was not included. Instead, cost of CHX was addressed as part of the breakeven analysis described below.
The analysis compared two treatment approaches: DCC (assumed to be standard of care) and CHX application (Figure 1). Patients were assumed to receive either CHX or DCC; however, in many low- and middle-income countries, mothers often choose to apply other remedies; such as methylated spirits and ash on the cord [3, 4]. As this analysis used data that reflects the WHO guidelines on recommended cord care [29] and the available clinical trial data [16, 17, 24], it does not include the use of other substances; therefore, it represents a conservative analysis. Neonatal mortality was not included in the model, only the effect of CHX on rates of omphalitis.
Breakeven analysis
Breakeven analysis was performed to ascertain the price of CHX that would lead to a net-neutral budget outcome, where any CHX price below this would allow savings from reducing omphalitis cases to be realised. This analysis was conducted from both perspectives, considering direct cost savings only and both direct and indirect cost savings.
One-way sensitivity analysis
A one-way sensitivity analysis was programmed to evaluate the robustness and sensitivity of results to changes in parameter values, to identify those parameters with the greatest influence on model outcomes. Upper and lower parameter values were based on ranges informed by plausible variation (±20%) and are shown in Supplementary Tables 1–6.