Estimating heterogeneous policy impacts using causal machine learning: a case study of health insurance reform in Indonesia

Policymakers seeking to target health policies efficiently towards specific population groups need to know which individuals stand to benefit the most from each of these policies. While traditional approaches for subgroup analyses are constrained to only consider a small number of pre-defined subgroups, recently proposed causal machine learning (CML) approaches help explore treatment-effect heterogeneity in a more flexible yet principled way. Causal forests use a generalisation of the random forest algorithm to estimate heterogenous treatment effects both at the individual and the subgroup level. Our paper aims to explore this approach in the setting of health policy evaluation with strong observed confounding, applied specifically to the context of mothers’ health insurance enrolment in Indonesia. Comparing two health insurance schemes (subsidised and contributory) against no insurance, we find beneficial average impacts of enrolment in contributory health insurance on maternal health care utilisation and infant mortality, but no impact of subsidised health insurance. The causal forest algorithm identified significant heterogeneity in the impacts of contributory insurance, not just along socioeconomic variables that we pre-specified (indicating higher benefits for poorer, less educated, and rural women), but also according to some other characteristics not foreseen prior to the analysis, suggesting in particular important geographical impact heterogeneity. Our study demonstrates the power of CML approaches to uncover unexpected heterogeneity in policy impacts. The findings from our evaluation of past health insurance expansions can potentially guide the re-design of the eligibility criteria for subsidised health insurance in Indonesia.

Health care utilisation following childhood acute lymphoblastic leukaemia: a population-based matched cohort study

ObjectivesSurvival among children diagnosed with acute lymphoblastic leukaemia (ALL) has increased considerably. However, morbidity in survivors constitutes a potential increasing burden not limited to secondary health care. Our objectives were to compare health care utilisation, including both primary and secondary health care, between childhood ALL survivors and matched references up to 15 years after curative treatment. Moreover, to increase knowledge on survivors’ health service seeking behaviour as time from treatment elapsed.Design and settingA Danish population-based matched cohort study linking multiple nationwide registries.Participants675 cases, diagnosed with childhood (1.0–17.9 years) ALL between 1994 and 2015, and 6750 matched references sampled randomly from the source population (matched on age, gender and geographical region).Primary outcome measuresRepeated consultations in general practice and hospital (outpatient and inpatient) estimated as yearly rates from 2.5 years after diagnosis and onwards. We compared cases and references with yearly incidence rate ratios (IRRs) from negative binomial regression models.ResultsSurvivors of childhood ALL had a mean number of yearly daytime contacts in general practice of 4.75 (95% CI 4.41 to 5.11) the first year, corresponding to an IRR of 1.85 (95% CI 1.71 to 2.00); decreasing to 1.16 (1.01 to 1.34) after 15 years, and without significant impact of gender (p=0.894) or age (p=0.399). For hospital contacts, ALL survivors had a mean number of yearly contacts of 14.21 (13.38–15.08) the first year, corresponding to an IRR of 31.50 (28.29–35.07); decreasing to 2.42 (1.59–3.68) after 15 years. No differences were found across calendar time.ConclusionsALL survivors used significantly more health care services across sectors than the reference population. Decreasing use over 15 years illustrated the dynamics of health care needs; this knowledge may inform the future organisation of integrated follow-up programmes.Trial registration numberNCT03985826.

EP.WE.84Palliative Care Interventions for Peripheral Vascular Disease: A Systematic Review

Objective Identify and evaluate palliative care interventions used in peripheral vascular disease (PVD). Background PVD encompasses conditions with poor outcome and severe suffering, both mentally and physically, yet utilisation and research into palliative care interventions remain sparse. Methods A systematic review of all study designs published between January 1991 and January 2020 in which people with PVD received palliative care interventions and at least one patient reported outcome was recorded. Results A total of eight studies involving 87037 unique patients met inclusion criteria (four cohort studies and four cross sectional studies). There were no randomised controlled studies; The small number of studies and study heterogeneity precluded meta-analysis. Only two papers recorded patient reported outcomes. Five papers found an association between palliative care and reduction in health care utilisation. Most of the studies reported that palliative care was likely underused. Only two of the studies included non-hospital patients. The methodological quality of the papers ranged from low to moderate. Conclusions Despite high mortality and morbidity associated with PVD, evidence of the effectiveness of palliative care in this group of patients is lacking. There are only a handful of papers on palliative care in vascular surgery and the majority are small, methodologically flawed and lack patient reported outcomes. Randomised controlled trials of palliative care interventions in patients with PVD are needed to determine optimal treatment outcomes.

SNAP participation and the health and health care utilisation of low-income adults and children

Objective: This article examined whether participation in the Supplemental Nutrition Assistance Program (SNAP) produced changes to adult and child health and health care utilisation during a period of economic recession. Design: Instrumental variables analysis relying on variation in state SNAP policies to isolate exogenous variation in household SNAP participation. Setting: Nationally representative data on child and adult health from the 2008 to 2013 National Health Interview Survey. Participants: Participants were 92 237 adults and 45 469 children who were either eligible for SNAP based on household income and state eligibility rules or were low income but not eligible for SNAP benefits. Results: For adults, SNAP participation increased the probability of reporting very good or excellent health, and for both adults and children, reduced needing but having to go without dental care or eyeglasses. The size of these benefits was especially pronounced for children. However, SNAP participation increased the probability of needing but not being able to afford prescription medicine, and increased psychological distress for adults and behavioural problems for children under age 10. Conclusions: SNAP’s benefits for adult health and improved access to dental and vision care for adults and children suggest benefits from the program’s expansions during the current COVID-induced crisis. Predicted negative effects of SNAP participation suggest the need for attention to program and benefit structure to avoid harm and the need for continued research to explore the causal effects of program participation.

The COVID-19 pandemic and ophthalmic care: a qualitative study of patients with neovascular age-related macular degeneration (nAMD)

Background/aims Concerns have been expressed about the relationship between reduced levels of health care utilisation and the COVID-19 pandemic. This study aimed to elicit and explore the views of patients with neovascular age-related macular degeneration (nAMD) regarding the COVID-19 pandemic and their ophthalmic care. Methods Between April 29th and September 4th 2020, semi-structured telephone interviews were conducted with thirty-five patients with nAMD taking part in a larger diagnostic accuracy study of home-monitoring tests. Participants were recruited using maximum variation sampling to capture a range of key characteristics including age, gender and time since initial treatment. Transcribed interview data were analysed using a deductive and inductive thematic approach. Results Three themes emerged from the analysis: i. access to eye clinic care. ii. COVID-19 mitigating factors and care delivery and iii. social and personal circumstances. Participants reported anxieties about cancelled or delayed appointments, limited communication from clinic-based services about appointments, and the impact of this on their ongoing care. Despite these concerns, there was apprehension about attending appointments due to infection risk and a perception that nAMD patients are a high risk group. Views of those who attended clinics during the study period were, however, positive, with social distancing and infection control measures providing reassurance. Conclusions These findings contribute to our understanding about experiences of patients with nAMD during the COVID-19 pandemic and have potential implications for future planning of care services. Innovative approaches may be required to address issues related to access to care, including concerns about delayed or cancelled appointments.

456 Palliative Care Interventions for Peripheral Vascular Disease: A Systematic Review

Objective Identify and evaluate palliative care interventions used in peripheral vascular disease (PVD). Background PVD encompasses conditions with poor outcome and severe suffering, both mentally and physically, yet utilisation and research into palliative care interventions remain sparse. Method A systematic review of all study designs published between January 1991 and January 2020 in which people with PVD received palliative care interventions and at least one patient reported outcome was recorded. Results A total of eight studies involving 87037 unique patients met inclusion criteria (four cohort studies and four cross sectional studies). There were no randomised controlled studies; The small number of studies and study heterogeneity precluded meta-analysis. Only two papers recorded patient reported outcomes. Five papers found an association between palliative care and reduction in health care utilisation. Most of the studies reported that palliative care was likely underused. Only two of the studies included non-hospital patients. The methodological quality of the papers ranged from low to moderate. Conclusions Despite high mortality and morbidity associated with PVD, evidence of the effectiveness of palliative care in this group of patients is lacking. There are only a handful of papers on palliative care in vascular surgery and the majority are small, methodologically flawed and lack patient reported outcomes. Randomised controlled trials of palliative care interventions in patients with PVD are needed to determine optimal treatment outcomes.

The utilisation of public and private health care among Australian women with diabetes: Findings from the 45 and Up Study

Aim To describe the prevalence of health care utilisation and out-of-pocket expenditure associated with the management of diabetes among Australian women aged 45 years and older. Design Cross-sectional survey design. Methods The questionnaire was administered to 392 women (a cohort of the 45 and Up Study) reporting a diagnosis of diabetes between August and November 2016. It asked about the use of conventional medicine, complementary medicine (CM) and self-prescribed treatments for diabetes and associated out-of-pocket spending. Results Most women (88.3%; n = 346) consulted at least one health care practitioner in the previous 12 months for their diabetes; 84.6% (n = 332) consulted a doctor, 44.4% (n = 174) consulted an allied health practitioner, and 20.4% (n = 80) consulted a CM practitioner. On average, the combined annual out-of-pocket health care expenditure was AU$492.6 per woman, which extrapolated to approximately AU$252 million per annum. Of this total figure, approximately AU$70 million was spent on CM per annum. Conclusions Women with diabetes use a diverse range of health services and incur significant out-of-pocket expense to manage their health. The degree to which the health care services women received were coordinated, or addressed their needs and preferences, warrants further exploration. Limitations of this study include the use of self-report and inability to generalise findings to other populations.