Introduction

In low- and middle-income countries (LMIC), the private healthcare sector is a critical stakeholder in health service delivery [1]. Country-specific evidence on the characteristics and performance of the private healthcare sector can inform national policy towards ensuring that healthcare services are accessible, affordable, equitable, and high quality [2]. Prior research across LMIC has found that private providers, while highly heterogeneous [1–3], are sometimes more user-centered and have more consistent equipment availability than public healthcare providers, while public providers can be more efficient, providing less potentially unnecessary testing and treatment, and linked to better patient outcomes [3, 4]. Studies specific to Latin American countries have found higher satisfaction, shorter wait times, and better medication access within private health services, although availability of recent data is limited [5–8].

Mexico’s healthcare system is complex, fragmented, and inequitable. Approximately 65% of the country’s 130 million people are affiliated with social security institutions that offer comprehensive economic, health, and social benefits to formal sector workers and their families [9]. Social security insitutions include the Instituto Mexicano de Seguridad Social (IMSS), the Instituto de Seguridad y Servicios Sociales de Trabajadores del Estado and social security institutions for oil, army and navy workers. Formal sector workers support financing of these plans through a payroll tax. Most of the remaining population is uninsured [10]. Uninsured individuals tend to have a lower socioeconomic status and less education than social security affiliates, and they rely on either public programs such as the IMSS-Bienestar program, or on the private health care sector. IMSS-Bienestar provides no-cost basic healthcare, but it does not provide care for chronic conditions requiring tertiary care services like cancer [11].

The private healthcare sector consists of independent and corporate providers and not-for-profit organizations. Two thirds of hospitals and over half of outpatient clinics are private [12]. In addition, there are approximately 15,000 doctors adjacent to, and employed by, pharmacies that provide ambulatory care [13]. Private healthcare is estimated to account for over half of care seeking in Mexico, and it only increased during the COVID-19 pandemic [10, 14, 15]. Most private sector services are paid out-of-pocket, as private insurance is uncommon (<10% of the population) and primarily covers hospital services [16]. In 2019, 42.1% of total health expenditure was out-of-pocket [17].

Research from the 2000s suggests that perceptions of better quality, shorter wait times, and better health outcomes in the private sector compared to the public sector contributed to higher rates of private healthcare utilization despite the cost [18, 19]. However, private pharmacy-adjacent doctors may provide substandard care by overprescribing medications and failing to comply with government regulations [20, 21]. Care quality is one of several individual and contextual factors shaping the choice of provider [22–24]. Several studies from the United States and Europe identified that users rely on their previous healthcare experiences when deciding where to receive healthcare [24], and confidence in government and healthcare providers more broadly is associated with greater intended health service uptake [25]. A recent (2022) study in Mexico found that 56% of the population that required healthcare in the last three months sought care in private health facilities, despite having the right to receive public healthcare. Out of those who chose private healthcare providers, 21% reporting doing so because of poor quality in public health facilities, such as long waiting times and unkind staff, while the rest cited access or other barriers [26]. Nevertheless, evidence on the role of the quality of public and private systems in shaping users’ choice of healthcare provider remains scarce [24, 27].

In this study, we aimed to (1) characterize private and public healthcare users based on individual and contextual factors, (2) compare users’ perceived quality of care between public and private providers, and (3) assess whether the perception of low quality of public healthcare services is associated with a greater probability of use of private healthcare.

Materials and methods

We performed secondary data analysis of the cross-sectional People’s Voice Survey conducted in Mexico from December 2022 to January 2023. This survey was developed by the QuEST Network, a global consortium for research on high-quality health systems (https://questnetwork.org) [28], and undertaken by the market research firm SSRS. The survey content was informed by the 2018 framework on high-quality health system domains and components [27, 28]. The survey applied random probability sampling to obtain a nationally representative sample of adults 18 years and older using a random digit dialing (RDD) approach from overlapping mobile and fixed phone frames. An RDD framework was built using the national numbering plan provided by Federal Telecommunications Institute. Based on the numbering plan, Sampling Solutions International developed a probabilistic design for pulling “seed” blocks from which actual phone numbers were generated, stratified by region according to the population distribution. The survey response rate was 3%. The survey sample included 1002 participants. Post-stratification weights were constructed based on demographic variables to account for differences in sample design and probability of selection. The final sample is, therefore, statistically projectable to the adult population in Mexico.

An expert group of the QuEST network designed, validated, and translated to Spanish the study questionnaire and adapted it for the Mexican context. Before the fieldwork, a pilot test of the questionnaire was performed to ensure language clarity. SSRS programmed the questionnaire using Computer Assisted Telephone Interviewing software.

Results

Of the 1,002 respondents, 811 reported at least one healthcare visit in the last year and hence were eligible for analysis. Ineligible respondents (n = 191) had less education and lower household income; and were less likely to have chronic diseases, social security health insurance, or a usual source of care (S1 Table).

Of the 811 healthcare users, 9% used pharmacy-adjacent doctors, 22.2% used stand-alone private healthcare providers, 43.5% social security providers and 25.3% used other public providers. The four groups did not show statistically significant differences in sex or age (Table 1). However, those attending stand-alone private providers were more likely to have ≥ 10 years of formal than public healthcare providers users. They were also more likely to belong to the middle- or higher-income groups. Almost 40% of private provider users had social security insurance. Only 9% of those using pharmacy-adjacent doctors’ and 25% of those using stand-alone private healthcare providers had private health insurance. Public healthcare users were more likely to have a usual source of care (91%) compared to private provider users (77.4%-80.5%).

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Table 1. Individual and contextual factors across users of private and public healthcare services in Mexico.

https://doi.org/10.1371/journal.pone.0306179.t001

Concerning health needs, there were no differences in self-rated health. Between 23.6% and 27% of respondents had chronic conditions, and less than 6.9% considered they had unmet health needs in the last year. Healthcare use was high overall: 51.2% reported at least four visits in the last year. For all users, the most frequent reason for the last visit was an urgent or new health problem. The majority of respondents who used doctors adjacent to pharmacies reported using them for an urgent or new health issue (82.7%).

More private and social security users lived in urban areas and in the richest regions, compared to the other public providers users. Public healthcare users were more likely to rate the overall quality of public healthcare services as good to excellent compared to private healthcare users.

Ratings of most recent visits by provider type are shown in Fig 1 and detailed in S2 Table.

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Fig 1. Rating of last visit quality by provider type and quality dimension.

https://doi.org/10.1371/journal.pone.0306179.g001

The proportion of users rating the visit as excellent or very good was highest for private providers for overall quality and each quality indicator, including more highly rated items like respectful treatment (57.4% rating excellent or very good overall, 68.9% within private providers) to the lowest rated items for availability of supplies and equipment (33.9% excellent or very good ratings overall, 50.8% within private providers) and wait time (29.4% excellent or very good overall, 42.3% within private providers). Pharmacy-adjacent doctors were rated less positively than private providers, though comparably for wait time and consultation duration. Less than half of the public healthcare users rated their most recent visit as excellent or very good quality overall; public sources were particularly poorly rated for availability of supplies and equipment and wait time.

Perception of overall quality in public health sectors was lower than overall quality of one’s own most recent visit, with 57% of respondents selecting fair or poor for at least one of the three public health systems; all three systems were rated similarly (S3 Table).

The multivariable analysis showed that, after adjusting for other conceptually relevant variables, those with fair or poor perception of overall quality in the public health sector were more likely to seek private healthcare (adjusted incidence rate ratio (aIRR): 1.95; 95% Confidence Intervals: 1.34, 2.82) (Table 2).

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Table 2. Association between users´ perception of quality in the public health sector with the likelihood of using private healthcare providers (Weighted N = 744).

https://doi.org/10.1371/journal.pone.0306179.t002

Discussion

The present study revealed frequent use of private healthcare services in Mexico, particularly by individuals with high education and income. A substantial proportion of private care users had no private health insurance. These users had access to presumably cheaper options: social security, IMSS-Bienestar or MoH, and other public care sources. Perceived quality was generally higher for private services and even for the pharmacy-adjacent doctors compared to public sources. Additionally, perceiving public health providers as poor quality was associated with a greater probability of private provider use.

Our study found socioeconomic differences between private and public health services users. Previous studies have shown that individuals with lower education, income, and no health insurance in Mexico have poorer health service use and worse health outcomes [20, 33, 34]. Most private healthcare users in Mexico lack private or social security health insurance, reducing their access to essential health services and resulting in high out-of-pocket expenditures when accessing care [20, 35].

Private healthcare users were more likely to rate their healthcare quality highly than public sector users. This finding has been typically reflected in less waiting time and more patient-centered care from private providers [18, 20]. In the present study, the most highly rated characteristics reported by participants attending private healthcare providers were respectful care, clarity of information, and technical knowledge and skills. This perception has been stable over the last decade in Mexico [18–20]. Compared to the National Health and Nutrition Survey (ENSANUT) 2012, our results showed similar users’ perceptions regarding the quality of care across the public and private health sectors. For instance, in 2012, the proportion of people who reported fair or poor quality of care was 11.3% for people who used pharmacy-adjacent doctors, 6.8% for stand-alone private healthcare providers, 22.4% for social security, and 16.9% for MoH [20]. In our study these percentages were 11.7%, 7.8%, 19.8%, and 18.6%, respectively.

Study findings must be situated in the current health policy situation in Mexico. Public health systems in Mexico have experienced substantial upheaval in recent years due not only to the COVID-19 pandemic but also to health policy shifts before and after the severe disruption of this public health emergency [36]. The Seguro Popular program and National Institute of Health for Wellness were terminated in 2019 and 2022, respectively. The subsequent reformulation of IMSS-Bienestar to provide healthcare to the uninsured and the federalization of services provided by state-level MoH secretariats is intended to address the gaps in public healthcare coverage, with unclear progress to date. At the same time, access to healthcare in Mexico remains inadequate, with 35 million people lacking public healthcare insurance coverage in 2021 [10]. Financial protection also remains insufficient even among those with access to insurance: 46.2% of the national health expenditures come from private expenditures, and more than 80% of private expenditures come from out-of-pocket expenditures [10]. Our study adds insights into the substantial deficit in quality of care based on user ratings of private sources versus public care and confirms that perceiving public healthcare as of low quality may drive people to use private services, as nearly 40% of private providers users were affiliated with social security institutions. This phenomenon undermines universal access to health services as it contributes to an increase in out-of-pocket expenditures, especially for Social Security beneficiaries who face a dual negative impact, as they not only pay the Social Security payroll tax but also incur out-of-pocket expenses for private healthcare services.

A study in India [37] similarly found that failure to meet users’ expectations can drive patients to private services, even if the clinical competence of private services may be lower. Public health services improvement is critical to increase citizens’ perception of quality and earn their trust in public health institutions, raising public health services use. To achieve this goal, as proposed by the Lancet Global Health Commission on High-Quality Health Systems [27], the Mexican government should strengthen the political commitment to improve the quality of public healthcare services, governing for quality by enacting necessary legislation, investing in the transformation of the health workforce to deliver people-centered high-quality care; and empowering users to demand such care. It is also important to guarantee easy access to the usual source of public health care, which should also provide high-quality services. Having a usual source of care was found to be associated with improved preventive services (cervical cancer screening, clinical breast exam, mammogram, prostate cancer screening, and flu shot) [38] and lower nonurgent emergency department use compared with no usual source of care [39], while in our study having a usual source of care was associated with the lower probability of using private healthcare providers.

The main study limitation is the cross-sectional design that does not allow temporal ordering of study variables; this analysis does not support causal inference. Furthermore, being secondary data analysis, some variables useful to explain health services use are not available, such as users’ functional status and health-related behaviors. Moreover, the study analyzed telephone survey data, which can be prone to social desirability bias when participants provide responses that they think are socially acceptable; however, physical distance between the interviewer and respondent, along with the respondent’s inability to see non-verbal signs, can lead to more sincere responses. Responses may be subject to uncertain recall, although we focused on perceived quality of the most recent healthcare visit to minimize recall time. In addition, the People’s Voice Survey in Mexico had a low response rate. The response rate can be negatively affected by the seasonal effect of conducting survey in December 2022 and January 2023, as some studies have found that survey participation rates tend to be lower during holiday periods [40, 41]. In addition, the growing violence in Mexico and fear of the people to disclose personal information might influence the low response rate [42]. However, it is worth noting that low response rates do not necessarily indicate nonresponse bias. “Nonresponse bias occurs when people who agree to participate in a survey are systematically different from those who refuse to participate” [43]. To ovoid nonresponse bias surveys should use statistical weighting to ensure that their sample is representative of the population with respect to geography, age, gender, education, and other relevant characteristics [43]. In the present study, to overcome the potential selection bias and to ensure that the study results were generalizable to the survey target population we applied survey sampling weights and we also used stabilized IP-weights to address missing information bias.

Conclusion

Most private healthcare providers’ users lack private health insurance and report a higher quality of healthcare received; the overall perception of public healthcare providers’ low quality is associated with a higher likelihood of private sector use, contributing to high out-of-pocket costs for users and potentially limited commitment to public health system improvement. The findings of this study call for stronger health system governance, focusing on improving access and quality throughout the Mexican public health system through people-centered policies and interventions.

Supporting information