Instrumental variable analysis for cost outcome: Application to the effect of primary care visit on medical cost among low-income adults.

Medical cost data often consist of zero values as well as extremely right-skewed positive values. A two-part model is a popular choice for analyzing medical cost data, where the first part models the probability of a positive cost using logistic regression and the second part models the positive cost using a lognormal or Gamma distribution. To address the unmeasured confounding in studies on cost outcome under two-part models, two instrumental variable (IV) methods, two-stage residual inclusion (2SRI) and two-stage prediction substitution (2SPS) are widely applied. However, previous literature demonstrated that both the 2SRI and the 2SPS could fail to consistently estimate the causal effect among compliers under standard IV assumptions for binary and survival outcomes. Our simulation studies confirmed that it continued to be the case for a two-part model, which is another nonlinear model. In this article, we develop a model-based IV approach, Instrumental Variable with Two-Part model (IV2P), to obtain a consistent estimate of the causal effect among compliers for cost outcome under standard IV assumptions. In addition, we develop sensitivity analysis approaches to allow the evaluation of the sensitivity of the causal conclusions to potential quantified violations of the exclusion restriction assumption and the randomization of IV assumption. We apply our method to a randomized cash incentive study to evaluate the effect of a primary care visit on medical cost among low-income adults newly covered by a primary care program.

Cost-outcome analysis of HIV testing and counseling, linkage, and defaulter tracing services in Bukoba, Tanzania.

Effective services along the HIV continuum of care from HIV testing and counseling to linkage, and from linkage to antiretroviral therapy (ART) initiation and retention, are key to improved health outcomes of persons living with HIV. A comprehensive analysis of the costs and outcomes of cascade services is needed to help allocate and prioritize resources to achieve UNAIDS targets. We evaluated the costs and population-level impact of a community-wide, integrated scale-up of testing, linkage, and defaulter-tracing programs implemented in Bukoba Municipal Council, Tanzania. Costs per identified HIV-positive client for provider-initiated, and home- and venue-based testing and counseling were $92.64 United States dollars (USD), $256.33 USD, and $281.57 USD, respectively. Costs per patient linked to HIV care and ART were $47.69 USD and $74.12 USD, respectively, during all ART-eligibility periods combined. Costs per defaulter traced and returned to HIV care were $47.56 USD and $206.77 USD, respectively. The provider-initiated testing and counseling was the most cost-effective modality. Testing approaches targeted to populations groups and geographic location with high testing positivity rates may improve the overall efficiency of testing services. The expansion of ART eligibility criteria and high linkage rate also result in efficiency gains and economies of scale of linkage services.

Scale Matters: A Cost-Outcome Analysis of an m-Health Intervention in Malawi.

BACKGROUND: The primary objectives of this study are to determine cost per user and cost per contact with users of a mobile health (m-health) intervention. The secondary objectives are to map costs to changes in maternal, newborn, and child health (MNCH) and to estimate costs of alternate implementation and usage scenarios. MATERIALS AND METHODS: A base cost model, constructed from recurrent costs and selected capital costs, was used to estimate average cost per user and per contact of an m-health intervention. This model was mapped to statistically significant changes in MNCH intermediate outcomes to determine the cost of improvements in MNCH indicators. Sensitivity analyses were conducted to estimate costs in alternate scenarios. RESULTS: The m-health intervention cost $29.33 per user and $4.33 per successful contact. The average cost for each user experiencing a change in an MNCH indicator ranged from $67 to $355. The sensitivity analyses showed that cost per user could be reduced by 48% if the service were to operate at full capacity. CONCLUSIONS: We believe that the intervention, operating at scale, has potential to be a cost-effective method for improving maternal and child health indicators.

Cost-Outcome Descriptive Study for Mobile App (UPSCALER) in the Rehabilitation of Anterior Cruciate Ligament (ACL) Injuries After Reconstructive Surgery.

Anterior cruciate ligament (ACL) injuries are a significant concern in athletes, often leading to long-term complications and reduced quality of life. Despite advancements in surgical techniques, outcomes following ACL reconstruction remain suboptimal, largely due to poor adherence to postoperative rehabilitation. This study introduces a novel postoperative rehabilitation approach utilizing a smartphone application, UPSCALER, developed by the Universiti Putra Malaysia Sports Injury and Arthroscopic Surgery Center of Excellence. The application delivers a validated accelerated rehabilitation protocol through instructional videos tailored to each patient's recovery phase. Results from the study demonstrate promising outcomes, including improvements in Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales post-rehabilitation, potentially attributed to increased adherence facilitated by the application's accessibility. Furthermore, the study explores the cost-effectiveness of this approach compared to conventional methods. In conclusion, smartphone application-guided rehabilitation shows promise in improving ACL reconstruction outcomes, warranting further research to validate its effectiveness and long-term impact on patient recovery and healthcare costs.

Does the neighborhood built and social environment reduce long-term care costs for Japanese older people? The JAGES2010-2019 cohort study.

Japan's population has been aging steadily, evidenced by it spending JPY 11 trillion (USD 110 billion) on annual long-term care (LTC) costs in 2021. In this context, understanding the factors influencing LTC costs has become increasingly vital. Although studies have reported positive relationships between neighborhood environment and health outcomes, the connection between LTC costs and neighborhood environment remains unclear. To address this gap in the literature, this cohort study, conducted from 2010 to 2019 across seven Japanese municipalities and involving 34,982 older people, examined the relationship between eight neighborhood environment elements and the mean monthly cumulate costs (MMCC) of LTC. The results showed that older people who reported the presence of fresh food stores nearby and dangerous places for walking alone at night in the neighborhood had lower MMCC, by JPY 1,367.6 and 1,383.3 per month, respectively, than respondents who did not report the presence of these neighborhood elements. Meanwhile, older people whose neighborhoods had easily accessible facilities had higher MMCC of JPY 739.4. This study's key findings reveal significant relationships between neighborhood environment elements and LTC costs and can be used to support developments in urban design to support healthy aging and reduced LTC costs.

Evaluation of Community-Based, Mobile HIV-Care, Peer-Delivered Linkage Case Management in Manzini Region, Eswatini.

The success of antiretroviral therapy (ART) requires continuous engagement in care and optimal levels of adherence to achieve sustained HIV viral suppression. We evaluated HIV-care cascade costs and outcomes of a community-based, mobile HIV-care, peer-delivered linkage case-management program (CommLink) implemented in Manzini region, Eswatini. Abstraction teams visited referral facilities during July 2019-April 2020 to locate, match, and abstract the clinical data of CommLink clients diagnosed between March 2016 and March 2018. An ingredients-based costing approach was used to assess economic costs associated with CommLink. The estimated total CommLink costs were $2 million. Personnel costs were the dominant component, followed by travel, commodities and supplies, and training. Costs per client tested positive were $499. Costs per client initiated on ART within 7, 30, and 90 days of diagnosis were $2114, $1634, and $1480, respectively. Costs per client initiated and retained on ART 6, 12, and 18 months after diagnosis were $2343, $2378, and $2462, respectively. CommLink outcomes and costs can help inform community-based HIV testing, linkage, and retention programs in other settings to strengthen effectiveness and improve efficiency.

Patient and program costs, and outcomes, of including gender-sensitive services in intensive inpatient programs for substance use.

Gender-sensitive services (GSS) attempt to make substance use treatment better for women, but at what cost and with what results? We sought answers to these questions in a federally-funded study by measuring separately the patient and provider costs of adding GSS, outcomes, and cost-outcome relationships for 12 mixed-gender intensive inpatient programs (IIP) that varied in amounts and types of GSS. GSS costs to female inpatients included time devoted to GSS and expenses for care of dependents while in the IIP. GSS costs to providers included time spent with patients, indirect services, treatment facilities, equipment, and materials. Offering more GSS was expected to consume more patient and provider resources. Offering more GSS also was expected to enhance outcomes and cost-outcome relationships. We found that average GSS costs to patients at the IIPs were $585 ($515-$656) per patient. Average GSS costs to providers at the IIPs were $344 ($42-$544) per patient. GSS costs to patients significantly exceeded GSS costs to providers. Contrary to previous research, offering more GSS services to patients did not result in significantly higher costs to patients or providers. IIPs offering more GSS may have delivered fewer traditional services, but this did not significantly affect outcomes, i.e., days until returning to another substance use treatment. In fact, median cost-outcome for these IIPs was a promising 35 treatment-free days, i.e., over a month, per $100 of GSS resources used by patients and providers.

Does Higher Spending Improve Survival Outcomes for Myocardial Infarction? Examining the Cost-Outcomes Relationship Using Time-Varying Covariates.

OBJECTIVES: Previous patient-level acute myocardial infarction (AMI) research has found higher hospital spending to be associated with improved survival; however, survivor-treatment selection bias traditionally has been overlooked. The purpose of this study was to examine the AMI cost-outcome relationship, taking into account this form of bias. DATA SOURCES: Hospital Discharge Abstract data tracked costs for AMI hospitalizations. Ontario Vital Statistics data tracked patient mortality. STUDY DESIGN: A standard Cox survival model was compared to an extended Cox model using hospital costs as a time-varying covariate to examine the impact of cost on 1-year survival in a cohort of 30,939 first-time AMI patients in Ontario, Canada, from 2007 to 2010. PRINCIPAL FINDINGS: Higher patient-level AMI spending decreased the hazard of dying (Standard Model: log-cost hazard ratio: 0.513, 95 percent CI: 0.479-0.549; Extended Model: log-cost hazard ratio: 0.700, 95 percent CI: 0.645-0.758); however, the protective effect was overestimated by 62 percent when survivor-treatment bias was overlooked. In the extended model, a 10 percent increase in spending was associated with a 3.6 percent decrease in hazard of death. CONCLUSION: The findings of this study suggest that if survivor-treatment bias is overlooked, future research may materially overstate the protective effect of patient-level spending on outcomes.