The present study found greater health service utilization by individuals with overweight and obesity, of both sexes, compared to under/normal-weight individuals. Individuals with hypertension or diabetes may need to use health services to a lesser or greater degree, and overweight and obesity influenced the extent of this utilization. The presence of obesity doubled the utilization of the health services investigated. One explanation for this higher use is that obesity may worsen the clinical condition of individuals with hypertension and/or diabetes, leading to the need for greater, or more frequent, health care. Another hypothesis is that, since obesity is a risk factor for other diseases, individuals with obesity needed to use health services more often after developing other NCDs, such as hypertension and diabetes.
These findings corroborate results seen in some high-income countries, such as Ireland [41], the USA (United States of America) [42], and Canada [43]. In Ireland, a representative study of the middle-aged and older adult population found that all obesity categories were associated with a higher number of GP visits [41]. In the USA, an eight-year retrospective cohort study of young and middle-aged adults revealed that obesity was associated with a higher rate of outpatient consultations, ER visits, and hospitalizations. Individuals with obesity had a two-fold greater risk of visiting the emergency room than normal-weight subjects, and weight gain over time was also associated with a higher risk of emergency room use [42]. In a five-year study, Canadians with a BMI ≥ 35 Kg/m2 made more GP visits than their normal-weight counterparts. Results of the study highlighted the burden of obesity, particularly in primary health care [43].
The present study identified an association between obesity and greater health service utilization in Brazil, a middle-income country. In addition, this increased use by individuals with obesity was found across all three levels of healthcare.
Greater health service utilization raises health costs, both in the private and public systems, particularly for higher-cost services such as hospital admissions, exams, and consultations with specialists [26, 28, 41, 42, 44]. Moreover, high demand for less accessible services, such as those requiring specialized staff and those that have limited hospital beds, can overload the health system, precluding care delivery or reducing the duration or quality of the service provided, since there will be much demand for the same service [45].
The study results showed higher health service utilization by women. The literature shows, among other factors, that culturally women have a greater tendency to seek healthcare services, compared to men [17, 24, 26, 46, 47].
Besides the fact that caring for one’s health is not regarded as a male pursuit, given that most primary and secondary healthcare services are not available during night-time hours or weekends, men, who still make up the majority of the formal workforce [48], may experience more difficulty accessing these services [24, 47]. Although not explained solely by access, it remains a key determinant of health service utilization [15]. Furthermore, the shortcomings of public services with regard to care, where users often face long waiting times and do not always have their health needs resolved in a single session, may pose another barrier to utilization by men. On top of these factors, men more often display a mindset of somehow “being unsusceptible to illness” [24, 47], reflecting a poorer perception of their need for healthcare, which itself may stem from lower use of these services [16].
Women also had the highest rates of hypertension and diabetes. This finding may suggest that, due to their greater propensity to seek healthcare services, women undergo more diagnostic exams and hence have a clearer picture of their true health situation [17]. Women also made greater use of services for follow-up treatment of the diseases (routine visits to doctor or health services use to realize exams). More rigorous disease follow-up suggests greater control and prevention of complications related to the disease [34].
The analysis of health service utilization for hypertension revealed a higher risk among the group of men with obesity for regular visits to doctor and for exams, compared to the utilization of these same services by women with obesity. In addition to obesity being associated with an increased risk of using all health services investigated, these findings reveal that gender also influenced the use of two of the four types of services investigated. In general, the risk of complications related to arterial hypertension was higher among men [49], where presenting obesity is expected to worsen the clinical condition of these individuals. This scenario, together with less frequent follow-up (and consequently less control) of the disease, would normally increase the need for the use of these services.
The cross-sectional nature of the present study does not allow inferring whether obesity preceded the diseases (given obesity is a risk factor for them), or whether weight gain (and consequently increased BMI) occurred after diagnosis of the diseases investigated. Nevertheless, in the present study, the association between the occurrence of obesity and greater health service utilization was clear.
This study has some limitations. It was not possible to distinguish between the two types of diabetes (types 1 and 2). Given that type 2 diabetes is more strongly linked with lifestyle, this type can better explain an association with obesity. However, because type 2 diabetes is more prevalent than type 1 [50], most individuals with this sub-diagnosis probably had the type 2.
Regarding race/skin color, two categories are composed of small numbers of individuals (indigenous and yellow), so it is difficult to conclude about them due to low precision. However, we chose to keep with these categories because we understand that is relevant to present descriptive data on this population, recognize their existence, and reflect the need for specific surveys related to these groups.
About the question: “routine visits to the doctor or health service for the disease”, it was not possible to quantify the number of visits, rendering the variable subject to interpretation, i.e. the concept of “routine” could have been interpreted differently by respondents.
In addition, this was a household-based study in which data on the presence of diseases and use of health services were reported by patients as opposed to being drawn from medical records, where this self-reporting may have led to under or overestimations. However, there is growing the use of self-reported information on morbidity in regular health surveys, despite its limitations, owing to the faster data collection and publication afforded. These factors, together with the inherently lower costs, make this approach useful and timely for health surveillance actions [35]. Also, the PNS did not collect data on health service access and we focused only on services related to hypertension and diabetes since only for those would be possible to assess all levels of healthcare (primary, secondary, tertiary).
It is also important to mention that, despite the data from the PNS-2019 being available, the survey had measured data only for a small subsample and self-referred data for all individuals. The present work analyzed the data from the PNS-2013 because, in this survey, the weight and height data were measured by trained professionals for the whole population, which eliminates reporting bias. As the objective of the present study was to analyze the association between obesity and the use of health services, and not to describe the prevalence, it is believed that the magnitude of the association is not influenced by this temporal difference.
Lastly, previous studies suggest that increased health service utilization by individuals with overweight or obesity is only partly explained by chronic health conditions [51, 52]. Thus, the findings of the present study may be underestimated, as the use of health services directly related to obesity was not investigated.
The underestimation of health services use by individuals with obesity may also be associated with social stigma in this group. A systematic review of observational studies on this issue found that 19.2–41.8% of individuals with obesity had been subject to discrimination [53], including healthcare-related discrimination, which can make them use less health services than they really need.
Therefore, the present findings likely represent a lower rate of use of these services than actually required by individuals with obesity. In addition, only two NCDs associated with obesity were assessed, while the literature shows obesity to be associated with many other NCDs [4, 7, 9, 54]. In addition, although in the present study no significant difference was found in the utilization of health services between individuals with an isolated or simultaneous diagnosis of hypertension and diabetes, it is known that the presence of multimorbidity may interfere with this utilization [19], which is a relevant point to be considered, especially for studies that assess a greater number of obesity-related diseases.
Taken together, the results showed that individuals with obesity made greater use of health services than their under/normal-weight counterparts, for both low and high-complexity services. Results of population-based studies, such as the present investigation, can significantly contribute to the planning, formulation, and management of health policies, particularly in the public sphere. Future studies on this subject should include data on access to health services and investigate health service utilization associated with the direct and indirect costs of obesity.