Data from: Cost-effectiveness of leveraging existing HIV primary health systems and community health workers for hypertension screening and treatment in Africa: An individual-based modelling study
Data files
Jan 06, 2025 version files 76.74 MB
-
create_wide_file.sas
90.93 KB
-
hiv_synthesis.sas
1.28 MB
-
README.md
17.24 KB
-
w_base_105_d3pct.sas7bdat
75.35 MB
Abstract
Background
Cardiovascular disease (CVD) morbidity and mortality is increasing in Africa, largely due to undiagnosed and untreated hypertension. Approaches that leverage existing primary health systems could improve hypertension treatment and reduce CVD, but cost-effectiveness is unknown. We evaluated the cost-effectiveness of population-level hypertension screening and implementation of chronic care clinics across eastern, southern, central, and western Africa.
Methods and Findings
We conducted a modelling study to simulate hypertension and CVD across 3000 scenarios representing a range of settings across eastern, southern, central, and western Africa. We evaluated two policies compared to current hypertension treatment: 1) expansion of HIV primary care clinics into chronic care clinics that provide hypertension treatment for all persons regardless of HIV status (chronic care clinic or CCC policy), and 2) CCC plus population-level hypertension screening of adults ≥40 years by community health workers (CHW policy). For our primary analysis, we used a cost-effectiveness threshold of US $500 per disability-adjusted life-year (DALY) averted, a 3% annual discount rate, and a 50-year time horizon. A strategy was considered cost-effective if it led to the lowest net DALYs, which is a measure of DALY burden that takes account of the DALY implications of the cost for a given cost-effectiveness threshold.
Among adults 45-64 years, CCC implementation would improve population-level hypertension control (the proportion of people with hypertension whose blood pressure is controlled) from mean 4% (90% range 1-7%) to 14% (6-26%); additional CHW screening would improve control to 44% (35-54%). Among all adults, CCC implementation would reduce ischemic heart disease (IHD) incidence by 10% (3-17%), strokes by 13% (5-23%), and CVD mortality by 9% (3-15%). CCC plus CHW screening would reduce IHD by 28% (19-36%), strokes by 36% (25-47%), and CVD mortality by 25% (17-34%). CHW screening was cost-effective in 62% of scenarios, CCC in 31%, and neither policy was cost-effective in 7% of scenarios. Pooling across setting-scenarios, incremental cost-effectiveness ratios were $69/DALY averted for CCC and $389/DALY averted adding CHW screening to CCC.
Conclusions
Leveraging existing healthcare infrastructure to implement population-level hypertension screening by CHWs and hypertension treatment through integrated chronic care clinics is expected to reduce CVD morbidity and mortality and is likely to be cost-effective in most settings across Africa.
README: Cost-effectiveness of leveraging existing HIV primary health systems and community health workers for hypertension screening and treatment in sub-Saharan Africa: An individual-based modelling study
https://doi.org/10.5061/dryad.5x69p8d9b
Description of the data and file structure
The data files consist of the HIV synthesis mathematical model, within which we have incorporated parameters for hypertension and cardiovascular disease. We ran the model (hiv_synthesis.sas) 3000 times to generate a variety of setting scenarios representative of settings across East, South, Central, and West Africa. We then summarized outcomes over a 50-year time horizon using the Create Wide file (create_wide.sas). The final dataset for primary analysis from the 3000 model runs is contained in w_base105_d3pct.sas7bdat.
This dataset includes model estimates for each of three policies: current standard of care (SOC), implementation of chronic care clinics delivering integrated HIV and hypertension services (CCC), and CCC plus community health worker screening of all adults in the community aged 40 and older (CHW). The CCC and CHW policies are implemented in 2024 and model estimates are included over both a 5-year and 50-year time horizon. Prior to 2024, we also include model estimates for the SOC condition to represent baseline and historical conditions for purposes of model calibration to historical data. Policies are indicated by the variable entitled 'option' (see table below). For CCC and CHW policies, model estimates for time periods prior to 2024 are missing (NA) since these policies are not implemented until 2024.
Description of variables in dataset
Dataset w_base105_d3pct.sas7bdat contains model output from the model runs used to generate the primary analysis of this manuscript. The dataset is in wide format with each row representing a single run of the model and each column including a variable. The table below provides a description of included variables. All variables are formatted with the base variable name, followed by the age range for which the values apply, and underscore, and then the year for which values apply. For example, the base variable 'prevalence' refers to the prevalence of HIV in the model output. 'prevalence1549m_15' indicates the prevalence of HIV among 15-49 year old men in 2015 (averaged across all four 3-month periods of 2015). Similarly, 'prevalence1549w_2474' indicates the prevalence of HIV among 15-49 year old women averaed across 2024-2074. The dataset also includes selected model parameters to allow stratified analysis to investigate the role that these parameters play in model estimates. Full description of all model parameters along with detailed justification for values chosen can be found in the supplemental appendix of the linked open-access manuscript.
| variable | description |
|---|---|
| run | model run ID |
| option | policy condition, implemented in 2024. 1=standard of care (SOC), 2=chronic care clinics (CCC), 3=community health worker screening (CHW) plus CCC |
| prevalence | HIV prevalence |
| ddaly | discounted disability-adjusted life years |
| inc_cat | demographic structure (see supplemental file in linked manuscript) |
| s_alive | number of adults currently alive in model |
| popsize | population size for each age band, with total population scaled to 10 million adults aged 15 and older |
| pop | number of adults currently alive in model, by age band |
| p_hypert | proportion with hypertension (current or pre-treatment SBP ≥140 or on antihypertensive medications) |
| p_htn_true | proportion with true hypertension (current or pre-treatment SBP ≥140) |
| p_dx_htn_true | proportion of people with true hypertension who are diagnosed |
| p_dx_htn_over | proportion of people with a hypertension diagnosis who do not have hypertension (max true SBP <140), i.e. overdiagnosis due to measurement error |
| p_diagnosed_hypert | proportion of people with hypertension who have a diagnosis (including those overdiagnosed) |
| p_on_tx_htn | proportion of people with true hypertension who are on treatment currently |
| p_hypert_control | proportion of people with true hypertension who have controlled blood pressure (current SBP <140) |
| p_on1drug_antihyp | proportion of people with hypertension who are currently on at least 1 drug treatment |
| p_on2drug_antihyp | proportion of people with hypertension who are currently on a 2nd drug for treatment |
| p_on3drug_antihyp | proportion of people with hypertension who are currently on a 3rd drug for treatment |
| p_ever_tx_htn | proportion of people with true hypertension who have ever been on treatment |
| p_on_tx_htn_over | proportion of people with hypertension overdiagnosis who are currently on treatment |
| p_ever_tx_htn_over | proportion of people with hypertension overdiagnosis who have ever been on treatment |
| p_hypertens160 | proportion of people with current moderate to severe hypertension (current SBP ≥160) |
| p_htn_true160 | proportion of people with ever moderate to severe hypertension (current or pre-treatment SBP ≥160) |
| p_dx_htn_true160 | proportion of people with a hypertension diagnosis among those with moderate to severe hypertension (current or pre-treatment SBP ≥160) |
| p_on_tx_htn160 | proportion of people currently on hypertension treatment among those with moderate to severe hypertension (current or pre-treatment SBP ≥160) |
| p_hypert_control160 | proportion of people with hypertension control among those with moderate to severe hypertension (pre-treatment SBP ≥160) |
| m_sbp | mean SBP among all adults in age band |
| m_sbp_max_over | mean maximum SBP among those with overdiagnosed hypertension |
| m_sbp_over | mean current SBP among those with overdiagnosed hypertension |
| n_ihd | number of ischemic heart disease events during period |
| n_cvd | number of cerebrovascular disease events during period |
| rate_ihd_modsev | rate of ischemic heart disease events that were at least moderate or severe (excuding asymptomatic/minimally symptomatic) per 100 person-years |
| rate_cva_modsev | rate of cerebrovascular disease events that were at least moderate or severe (excuding asymptomatic/minimally symptomatic) per 100 person-years |
| prev_ihd | prevalence of ischemic heart disease |
| prev_cva | prevalence of cerebrovascular disease |
| rate_dead_cvd | mortality rate from cardiovascular disease per 100 person-years (combined ischemic heart disease and cerebrovascular disease) |
| n_dead_cvd | number of deaths from cardiovascular disease |
| rate_dead_hivpos_cvd | mortality rate from cardiovascular disease per 100 person-years among people living with HIV |
| rate_dead_hivpos_ac | mortality rate from all causes per 100 person-years among people living with HIV |
| rate_dead_hivneg_cvd | mortality rate from cardiovascular disease per 100 person-years among people without HIV |
| rate_dead_hivneg_ac | mortality rate from all causes per 100 person-years among people living without HIV |
| n_dead_all_anycause | number of deaths from all causes during period (among all adults aged ≥15 years) |
| rate_dead_all_anycause | mortality rate from all causes during period (among all adults aged ≥15 years) |
| n_dead_ac | number of deaths from all causes during period (among all adults aged ≥18 years) |
| rate_dead_ac | mortality rate from all causes during period (among all adults aged ≥18 years) |
| htn_cost_total | total undiscounted costs of hypertension care |
| htn_cost_scr | undiscounted costs of hypertension screening (CHW policy only) |
| htn_cost_drug | undiscounted cost of hypertension medications |
| htn_cost_clin | undiscounted costs of hypertension clinic visits |
| htn_cost_cvd | undiscounted costs of emergency care for CVD events |
| dhtn_cost_total | total discounted costs of hypertension care, discounted by 3% per year |
| dhtn_cost_scr | discounted costs of hypertension screening (CHW policy only) |
| dhtn_cost_drug | discounted cost of hypertension medications |
| dhtn_cost_clin | discounted costs of hypertension clinic visits |
| dhtn_cost_cvd | discounted costs of emergency care for CVD events |
| dhtn_cost_totdrughalf | total discounted costs of hypertension care when drug costs set to 50% |
| dhtn_cost_totdrugdoub | total discounted costs of hypertension care when drug costs set to 200% |
| dhtn_cost_totclinhalf | total discounted costs of hypertension care when clinic visit costs set to 50% |
| dhtn_cost_totclindoub | total discounted costs of hypertension care when clinic visit costs set to 200% |
| dhtn_cost_totscrnhalf | total discounted costs of hypertension care when screening costs set to 50% |
| dhtn_cost_totscrndoub | total discounted costs of hypertension care when screening costs set to 200% |
| dhtn_cost_tothalf | total discounted costs of hypertension care with all costs set to 50% |
| dhtn_cost_totdoub | total discounted costs of hypertension care with all costs set to 200% |
| dhtn_cost_totcvdquart | total discounted costs of hypertension care when emergency CVD costs set to 25% |
| dhtn_cost_totcvdhalf | total discounted costs of hypertension care when emergency CVD costs set to 50% |
| dhtn_cost_totcvddoub | total discounted costs of hypertension care when emergency CVD costs set to 200% |
| dhtn_cost_totcvd4x | total discounted costs of hypertension care when emergency CVD costs set to 400% |
| cost_lowqual_cvdcare | model parameter: relative cost of receiving low-quality care for a CVD event, compared to high-quality care |
| prob_sbp_increase | model parameter: risk of a 1 mmHg increase in true SBP per 3-month period (cumulative with other individual-level modifiers, models increases in SBP with age) |
| sbp_cal_eff | model parameter: risk of population-level rise in SBP by 1 mmHg after 2015 (models potential increase in SBP at population level with calendar time) |
| rr_cvd_tx | model parameter: relative risk of CVD events receiving acute treatment, multiplied by base assumption of 40% |
| rr_cvd_tx_effective | model parameter: relative risk of CVD care being effective for reducing acute mortality, multiplied by base assumption of 25% |
| prob_htn_link | model parameter: probability of linking to clinic for hypertension care following measured SBP ≥140 mmHg at community screening |