Consumer Cost-Sharing in Primary Care: Unintended Health and Economic Outcomes

Lead Research Organisation: University College London
Department Name: Economics

Abstract

In many countries, even insured individuals must pay a fee (usually patient cost-sharing) to see their family doctor. The theoretical purpose of that fee is one of cost-containment: to limit the overuse of doctor visits, although it can also play a role in the funding the health system.

An unintended consequence of such fees is that they might prevent individuals from visiting their family doctor for necessary medical conditions. Hence, individuals' health might deteriorate, and in the future they might need much more expensive medical treatments (e.g. hospitalizations), which would defeat the cost containment purpose that the fee was supposed to serve.

The importance of this unintended consequence might be growing with the rapid increase in Non-Communicable Diseases (NCDs), which require timely diagnosis and management through primary care services. For many NCDs, it is easier to postpone doctor visits because they are not painful in their initial stages (e.g. diabetes), but if they are not diagnosed timely and appropriately managed, they will lead to more expensive medical procedures in the future. Visiting the family doctor might help to diagnose the conditions timely, as well as to keep an adequate management of such conditions.

Hence, patient fees might be favoring use of hospitals instead of primary care services, which is inefficient because hospital services are much costlier. This inefficiency weakens the health system and limits how much the health system can improve in other dimensions (coverage, quality improvement).

Although the literature has been interested in this topic, most previous research has reported associations, which might be spurious. Some recent papers have been able to estimate the effect of patient fees on health, but they have not been able to assess how health care use patterns or overall treatment costs change. These are key issues to understand how patient fees affect the health system (split of resources between primary and secondary care), and its efficiency.

To contribute to this debate, we will be testing whether (and by how much) increased patient fees in primary care increase undiagnosed chronic conditions, adverse health outcomes, mortality, use of hospital services, and treatment costs both in the short and long term (up to 7 years).

To conduct this work, we will be using health administrative data for the years 2011 to 2018, covering 97% of the Colombian population and containing patients records of all health care services provided in the Colombian Health System, including date and type of service used (outpatient, hospital, etc), prescriptions, treatment costs, ICD-10, sociodemographic characteristics of individuals (including income or wealth scores) and mortality. The person identifier is consistent across the seven years, providing a uniquely rich and detailed longitudinal administrative database. Moreover, its huge size allows us to estimate the effects of interest for particular subpopulations of interest (e.g. individuals with poor socio-economic status, or chronic patients).

However, data is not enough to provide a robust answer to the question of interest. We also need a method to be sure that we will not be reporting spurious associations in the data. Experiments are usually used for that purpose but they are unlikely to provide us with long term effects as the ones that we will be estimating, nor the samples be large enough.

We are fortunate enough that the patient cost-sharing system in Colombia works "in abrupt jumps," that is, cost-sharing jumps abruptly at pre-specified thresholds of some continuous variables. This is the ideal setting to apply a quasi-experimental method called Regression Discontinuity (RD), which is known to provide causal estimates, free of spurious correlations, under very weak assumptions. Note that you cannot use RD whenever you want, the conditions must be there, but we are fortunate that they do hold in Colombia.

Technical Summary

The main objective of this proposal is to establish whether increased levels of patient cost-sharing reduce the use of primary care services, and increase undiagnosed chronic conditions, hospitalizations, health care costs, and mortality. To fulfill this objective, we need:

(a) a dataset representative of the population, and that is large enough so that effects on hospitalizations, chronic condition diagnosis, and mortality can be precisely estimated, not only for the entire population, but also for subgroups of especial interest (e.g. poor SES individuals);

(b) An empirical design that will allow the researchers to go beyond associations, and estimate the causal impact of patient cost-sharing on the relevant outcomes in the absence of an experiment.

Regarding (a), the data for this proposal consists of health administrative data for the years 2011 to 2018, covering 97% of the Colombian population and containing patients records of all health care services provided in the Colombian Health System, including date and type of service used (outpatient, hospital, etc.), prescriptions, treatment costs, ICD-10 codes, sociodemographic characteristics of individuals (including income or wealth scores) and mortality. The person identifier is consistent across the seven years, providing a uniquely rich and detailed longitudinal administrative database.

Regarding (b), We will exploit a unique feature of the Colombian Health System that makes it particularly suitable to the use of the Regression Discontinuity quasi-experimental method: the level of patient cost-sharing changes abruptly at determined thresholds of a continuous variable. The Regression Discontinuity method is highly regarded for its ability to estimate causal estimates (Lee and Lemieux 2010).

The results of the study constitute the first step towards investigating the consequences of consumer cost-sharing to health systems in middle income countries, which will be pursued in a future proposal.

Planned Impact

This research will benefit the Ministry of Health and Social Protection in Colombia, as well as the managers of public and private insurance funds in Colombia. Thanks to this research, they will learn how health outcomes (including chronic conditions and mortality), health care utilization patterns (primary vs. secondary care) and health care costs in the short and longer term (both in primary and secondary care) will change if the level of patient cost-sharing changes. This is vital information to improve the efficiency of the health system, as well as to plan future investments in the sector.

This research will also benefit Colombian citizens because the results of their research will inform how their health will improve if patient cost-sharing decreases or is eliminated. The research will also inform how to obtain efficiency gains in the system, which will ultimately lead to lower payroll contributions and taxes, or better health outcomes for the same payroll contributions and taxes.

The research will also benefit policy makers from other countries. Patient cost-sharing is a very active area of policy making, as it plays a very important role in the health coverage system, and Universal Health Coverage has gained great importance in the policy arena. The results of our research will provide very important information to policy makers on the consequences of patient cost-sharing on health, health care utilization patterns, and health care costs, both in the short and longer term. Because we will provide evidence on all the steps of the causal chain, estimates for different sub groups (by socio-economic status, chronic conditions, age, gender, etc), and extensive contextualized information, international policy makers will be in a good position to think how our results translate into their setting.

This research will also benefit international institutions, such as the World Health Organization, Pan American Health Organization, World Bank, and Inter-American Development Bank, who will have more information on the consequences of patient cost-sharing and will be better informed to influence policy and how to advise governments. This is very important in light of worldwide progress towards Universal Health Coverage.

Some NGOs and advocacy groups also play a very important role in shaping health policy internationally, and our research will provide them with rigorous information on how patient cost-sharing affects health outcomes, utilization patterns, and health care costs.
 
Description Citation in "A systematic review of strategies used for controlling consumer moral hazard in health systems"
Geographic Reach Multiple continents/international 
Policy Influence Type Citation in systematic reviews
URL https://doi.org/10.1186/s12913-022-08613-y
 
Description Exchange of ideas with policy maker on cost-sharing based on preliminary results of our study
Geographic Reach South America 
Policy Influence Type Implementation circular/rapid advice/letter to e.g. Ministry of Health
 
Description Meetings with the Health Secretariat of Bogota
Geographic Reach South America 
Policy Influence Type Implementation circular/rapid advice/letter to e.g. Ministry of Health
URL https://www.saludcapital.gov.co/Paginas2/Noticia_Portal_Detalle.aspx?IP=2140
 
Description Particpation in advisory committee on risk-adjustment to reduce health inequalities
Geographic Reach South America 
Policy Influence Type Participation in a guidance/advisory committee
 
Description Presentation of our results in a private meeting to the two Colombian Vice-Ministers of Health
Geographic Reach South America 
Policy Influence Type Implementation circular/rapid advice/letter to e.g. Ministry of Health
 
Description Workshop on Regression discontinuity technique
Geographic Reach South America 
Policy Influence Type Influenced training of practitioners or researchers
Impact Attendees can now apply regression discontinuity techniques to their analysis.
 
Description UKRI GCRF Newton Institutional Consolidated Impact Account
Amount £6,299 (GBP)
Funding ID GNCA Award Number: 185337 
Organisation University College London 
Sector Academic/University
Country United Kingdom
Start 03/2022 
End 03/2023
 
Title New high performance computer for demanding statistical analysis. 
Description (1) New high performance computer for demanding statistical analysis. We could apply cutting edge statistical methods thanks to this High Performance Computer. This led to more solid and interesting results of our project. (2) Newly produced (3) n/a (4) Has been and is being used in Colombia (ODA) 
Type Of Material Improvements to research infrastructure 
Year Produced 2022 
Provided To Others? No  
Impact We could apply cutting edge statistical methods thanks to this High Performance Computer. This led to more solid and interesting results of our project. 
 
Title Model to calculate the Charlson index from health insurance claim databases 
Description Model to calculate the Charlson index from health insurance claim databases 
Type Of Material Computer model/algorithm 
Year Produced 2024 
Provided To Others? Yes  
Impact It allow us to show the mechanisms, and explain the results that we obtain. Used in Colombia (ODA) by 3 people Used in USA by 1 person Used in UK by 1 person 
URL https://github.com/Instituto-de-Investigaciones-Clinicas/Cost_Sharing_Colombia_Public
 
Title Model to estimate dynamic regression discontinuity estimates. 
Description We have developed a new computer code that is able to estimate the different parameters of a dynamic regression discontinuity design: intention to treat, treatment on the treated, and transition probabilities. Our code can also estimate the standard errors and confidence intervals. 
Type Of Material Computer model/algorithm 
Year Produced 2024 
Provided To Others? Yes  
Impact We could obtain more robust and interesting results thanks to the use of this new code. Used in Colombia by 2 people Used in UK by 1 person 
URL https://github.com/Instituto-de-Investigaciones-Clinicas/Cost_Sharing_Colombia_Public
 
Title Survival analysis using regression discontinuity 
Description We provide the code to estimate a Weibull model of survival combined with regression discontinuity. 
Type Of Material Data analysis technique 
Year Produced 2024 
Provided To Others? Yes  
Impact It allowed us to estimate the effect of the cost-sharing on survival, whilst taking into account censoring. Used in Colombia (ODA) by 2 people Used in UK by 1 person 
URL https://github.com/Instituto-de-Investigaciones-Clinicas/Cost_Sharing_Colombia_Public
 
Description Collaboration with Stanford University 
Organisation Stanford University School of Medicine
Country United States 
Sector Academic/University 
PI Contribution Prof. Grant Miller is gaining deep insights into the functioning of consumer cost-sharing in Colombia, as well as on dynamic regression discontinuity methods.
Collaborator Contribution Prof. Grant Miller is collaborating with the research team on the research. He has also provided access to high performance computing resources at Stanford University.
Impact It will result in a research paper.
Start Year 2022
 
Description Partnership with Universidad Nacional de Colombia 
Organisation National University of Colombia
Country Colombia 
Sector Academic/University 
PI Contribution This the partnership which was included in the original application. UCL has provided expertise on econometric methods to estimate the impact of cost-sharing on health care use and health outcomes in Colombia. UCL has also provided use of a High Performance Computer, and the team in Colombia has learnt how to use such High Performance Computer. UCL has also taught (for free) a course on Regression Discontinuity methods to policy makers and students at the Universidad Nacional de Colombia.
Collaborator Contribution Universidad Nacional de Colombia has provided expertise on the functioning of the Colombian Health Care System Universidad Nacional de Colombia has provided access to very rich data which would not be available otherwise.
Impact This is a multidisciplinary collaboration involving the Department of Economics at UCL, and the Faculty of Medicine at the Universidad Nacional de Colombia. Outputs: -The publications listed as outputs -The computer programs listed as outputs To build equity into the partnership, the Colombian Co-PI has presented the work in several conferences. He has gained exposure and recognition as a result, and he has been invited to be part of a Global Health NIHR funding committe. He has been in the UK attending the NIHR funding committee. The partnership is still active. We are waiting to hear about a joint research proposal that we have submitted to ESRC, and another one to MRC, and we are working to submit a new research proposal to NIHR this June.
Start Year 2020
 
Description Presentation at the 6th Annual Health Financing Reform at The World Bank 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Policymakers/politicians
Results and Impact Presentation at the 6th Annual Health Financing Reform at The World Bank. The presentation raised awareness amongst policymakers of low and middle-income countries that consumer cost-sharing can lead to worse health outcomes and increased mortality.
Year(s) Of Engagement Activity 2022
URL https://www.worldbank.org/en/events/2022/06/14/financing-primary-health-care-opportunities-at-the-bo...
 
Description Workshop on regression discontinuity method to estimate the effect of health interventions in Colombia 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Policymakers/politicians
Results and Impact Description: The workshop discussed about regression discontinuity method apply to health interventions.
Impact: Attendees will be able to apply the learnt techniques to analysis of different policies.
Countries: UK and Colombia (ODA)
Organisations:
-Universidad Nacional de Colombia
-University College London
-Staff from several hospitals
-National Department of Statistics
-Super salud (insurance regulator)
-Econometria Consultores (private consultancy)
-60 attendees
Types of stakeholders: academia, private sector, hospitals, policy makers, third sector
Year(s) Of Engagement Activity 2023