Association of Health-Related Quality of Life with Breast Cancer Survival among Hispanic Population Using 10 Years of MEPS National Sample Cohort Data

Background: Breast cancer is the most commonly diagnosed cancer among women in the United States and it is the leading cause of death among the Hispanic population. Little evidence exists the association of health-related quality of life (HRQoL) by the presence of breast cancer survival among the Latina population. This study was to look at the association of the presence of breast cancer survival on HRQoL measure in the US Hispanic population. Methods: This was a cross-sectional study analyzing data from the 2006-2015 Medical Expenditure Panel Survey (MEPS). The target population was comprised of Hispanic community-dwelling residents with breast cancer in the US. Two multivariate regression models were used to predict HRQoL measure by the presence of breast cancer survival among the Hispanic population. Results: A total 207 breast cancer survivors met the study inclusion criteria, and the estimated population size was 1.200,337 breast cancer survivors. In the multiple regression analysis on the SF-12 PCS scores, age, census region, poverty level, perceived health status, BMI, and employment were associated with SF12 PCS scores. The multiple regression analysis on the SF-12 MCS scores presented that age, census region, insurance type, perceived mental health status, and CCI were associated with SF-12 MCS scores. Conclusion: This study presents data on the HRQoL of Hispanic breast cancer survivors in the U.S. It builds on previous research that examines the HRQoL as expressed through the SF-12 PCS and SF-12 MCS surveys, rather than other types of measurement. This study may also be used as a guide in the implementation of clinical interventions and plans for survivorship care in improving the HRQoL of Hispanic breast cancer survivors. © 2020 Jongwha Chang. Hosting by Science Repository. All rights reserved


Introduction
Breast cancer is the most commonly diagnosed cancer among women in the United States and it is the leading cause of death among the Hispanic population. The incidence of breast cancer in the U.S. is amongst the highest in the world. It is predicted that there will be about 268,600 new breast cancer cases and that the disease will cause about 41,760 deaths in women in the U.S. in 2019 [1][2][3]. In the U.S., it is reported that about 1 in 8 will develop breast cancer during their lifetime [1].These statistical facts show similar trends in the Hispanic/Latino population, a group which is considered to be one of the fastest growing minorities as well as the largest and youngest minority group in the U.S [4]. It is estimated that about 1 in 10 Hispanic women living in the U.S. will develop breast cancer in their lifetime [4,5]. In the diagnosis, treatment, screening and recurrence of breast cancer, different factors such as anxiety and other comorbidities, are observed to play a significant effect on the patient's health outcomes, either causing a delay in or disregard of preventative measures [6]. The various other factors, to a certain degree, can dramatically interfere with the health-related quality of life (HRQoL) in breast cancer survivors.
Today, even as improvements in early detection and treatment of breast cancer have now resulted in a greater number of women being diagnosed earlier and are living longer after diagnosis [7]. Breast cancer survivors were still reported to have a decreased physical, mental, emotional and social functioning as compared to the general population without cancer. An assessment of patients' quality of life has been shown to contribute to their improved treatment and could further be used to predict the chance of recovery or relapse from the disease [7,8]. In past research on cancer, HRQoL has been considered to be an important end-point [9]. The HRQoL assessment generally takes into account levels of physical, mental, social, and role functioning, including abilities, relationships, perceptions, life satisfaction, and well-being [10]. In the case of Hispanic women with breast cancer, we take into account the following to be predictors of HRQoL: predisposing factors such as gender, race, ethnicity, and age; enabling factors such as marital status, education, employment, poverty status, insurance coverage, and usual source of care; health care maintenance needs on perceived physical and mental health status, BMI, and other chronic conditions; personal health practices such as smoking status; and external environment or geographical location.
A review of the literature on cancer survivorship suggests the need to investigate the long-term outcomes related to the physical, mental and social aspects associated with HRQoL in breast cancer survivors [11][12][13][14]. There is also a need to look into the disparities in access to screening, diagnosis, care and treatment that the Hispanic/Latino population continues to experience that seems to result in lower HRQoL in breast cancer survivors in this group [5,[15][16][17]. In addition, certain lifestyle factors, such as weight management, obesity and an unhealthy lifestyle, income, sociodemographic factors, comorbidities, age at first birth, number of children, and length of breastfeeding, and a person's cultural or ethnic background or region, was significantly related to lower HRQoL in this population [18,19]. Other studies further elucidate the greater degree of unmet supportive care needs in this population compared to non-Hispanic/Latino white women and how this affects both satisfaction with cancer care as well as health-related quality of life in this group [5,16,17,20,21]. This further supports the fact that more quantitative research is needed for a better understanding of the topic [14,22,23]. Over the past ten years, a lot of advances and clinical trials has been directed to the treatment of breast cancer in order to improve survival [7]. However, it is important to note that assessment of factors related to HRQoL will contribute to the improved outcomes in breast cancer care, both during treatment, remission, and survival. As the expected number of breast cancer incidences and survivors from this population continues to rise, a closer investigation into the factors that affect their health-related quality of life is becoming more important. The primary objective of this study was to investigate which factors have a significant effect on the health-related quality of life among breast cancer survivors in the US Hispanic population. It also aimed to further identify which of these factors had the greatest impact on the healthrelated quality of life among breast cancer survivors from this population.

I Data Source
As a retrospective data study, data from the 2006-2015 Medical Expenditure Panel Survey (MEPS) were used for these analyses. MEPS is a set of large-scale surveys of families and individuals, their medical providers, including doctors, hospitals, and pharmacies, and employers across the United States [24]. MEPS is a complete source of data on the cost and use of health care and health insurance coverage [24]. The analytic focus of MEPS has been directed to the topics of health care access, coverage, cost, self-or caregiver-reported information [25]. Also, MEPS provides continuous and current estimates of healthcare utilization and expenditure at both the individual and household level for two panels for each calendar year [26,27]. Institutional Review Board (IRB) approval was waived since MEPS data is publicly available deidentified data. The 12-Item Short-Form Health Survey (SF-12) is weighted and summed to provide easily interpretable scales for physical and mental health. The SF-12 questions are as follows [28]:

II Patient Selection and Outcomes Measures
i. General health today ii.
During a typical day, limitations in moderate activities iii.
During a typical day, limitations in climbing several flights of stairs iv.
During the past 4 weeks, as result of physical health, accomplished less than would like v.
During the past 4 weeks, as result of physical health, limited in kind of work or other activities vi.
During the past 4 weeks, as result of mental problems, accomplished less than you would like vii.
During the past 4 weeks, as result of mental problems, did work or other activities less carefully than usual viii.
During the past 4 weeks, pain interfered with normal work outside the home and housework ix.
During the past 4 weeks, felt calm and peaceful x.
During the past 4 weeks, had a lot of energy xi.
During the past 4 weeks, felt downhearted and depressed xii.
During the past 4 weeks, physical health or emotional problems interfered with social activities The PCS and MCS are computed using the scores of twelve questions, which have three or five-level Likert scale, where a lower score indicates the lowest level of health measured by the scales and a high score indicates the highest level of health [28]. The scoring algorithms for both the PCS and MCS incorporate information from all questions. The PCS weights more heavily were addressed for the following questions: 1, 2, 3, 4, 5, and 8, while the MCS weights more heavily responded to the following questions: 6, 7, 9, 11, and 12 [24]. Andersen's behavioural model was used to assess factors associated with QOL in breast cancer survivors [29]. Independent variables were derived from the conceptual framework, using five predictors: 1) predisposing-race, Hispanic ethnicity, and age; 2) enabling-marital status, education, employment, poverty status, insurance coverage, and usual source of care; 3) needperceived physical and mental health status, body mass index (BMI), Charlson Comorbidity Index (CCI), other chronic conditions; 4) personal health practices-smoking status; and 5) external environment-geographical region.

III Statistical Analyses
Because MEPS employed complex, multistage sampling design, to represent the overall population, responses of the surveyed individuals need to be weighted by the proportion of the population they represent.
The person weights provided in the MEPS were used to derive national estimates of demographics and socioeconomics covariates. The number of respondents with breast cancer and the weighted sample size were presented. The SF-12 scores were weighted using special weight variables, which were designed to be used with the self-administration questionnaire (SAQ) for persons who aged 18 and older at the interview date. This weight adjusts for SAQ non-respondents and weights to the U.S. civilian noninstitutionalized population [24]. The multivariate regression models were performed to predict MCS and PCS scores among the Hispanic population controlling for covariates. An accurate point estimates and its standard errors for the nationally representative population incorporating the MEPS survey weights were calculated using the 'proc survey' procedure of SAS and the 'svy' procedure of Stata [30]. All analyses were conducted using SAS version 9.4 (SAS Institute Inc., Cary, NC) and Stata version 12 (Stata Corp. LP, College Station, TX). All statistical analyses were 2-tailed, and the significance level was set a priori at P < 0.05.

Results
In total, 332,284 (weighted sample size Table 3 summarized the findings pertaining to the factors associated with HRQoL in the Hispanic population with breast cancer using the multiple regression analysis. In the multiple regression analysis on the SF-12 PCS scores, age, census region, poverty level, perceived health status, BMI, and employment were associated with SF-12 PCS scores. The PCS scores in patients aged 18-44 were significantly higher by 6.76 compared to elderly group, controlling for covariates (β=6.76, SE=2.70, p=0.013). The poverty level had an impact on the PCS: patients with poor or low income reported significantly lower scores than those with high income (β=-4.81, SE=2.41, p=0.047). The level of perceived health status was positively associated with PSC scores. Patients perceiving fair or poor health status showed 7.6 lower scores compared to excellent or very good health status (β=-7.59, SE=2.67, p=0.005). Obesity patients also had lower scores than overweighed patients (β=-5.00, SE=1.77, p=0.005). The PCS scores for employed patients were higher than those of non-employed patients (β=6.51, SE=2.16, p=0.003). The multiple regression analysis on the SF-12 MCS scores presented that age, census region, insurance type, perceived mental health status, and CCI were associated with SF-12 MCS scores. Patients aged 18-44 had lower MCS scores than more than 65 aged patients (β=-5.98, SE=2.00, p=0.003). In addition, 45-64 aged patients had 7 lower scores than elderly (β=-7.10, SE=1.63, p<0.001). Compared to patients who reside in West areas, Midwest or South area had significantly lower scores (p<0.05). Insurance type was a significant factor for SF-12 MCS scores. Private or public insurance was associated with higher MCS scores (β=11.38, SE=3.60, p=0.002; β=5.00, SE=2.24, p=0.026, respectively). Patients with worse perceived mental health status showed lower scores (β=-10.80, SE=2.88, p<0.001). Less comorbidities were associated with higher MCS scores (β=4.11, SE=1.85, p=0.027).

Discussion
Health-Related Quality of Life (HRQoL) is an extensive measurement of an individual's subjective evaluation of his or her physical, emotional, and social well-being over time. In this study, it was utilized to measure how breast cancer has affected Hispanic women who survived the disease. The primary objective of the study was to determine the relationship between a breast cancer survivors' HRQoL with five significant factors: 1) predisposing factors (gender, age, race, and ethnicity), 2) enabling factors (marital status, education, employment, economic status, insurance coverage and usual source of care), 3) need, 4) personal health practices, and 5) external environment. The secondary objective was to determine which of the given factors has the greatest impact on the health-related quality of life among breast cancer survivors from the US Hispanic Population. The results of the study showed that there is a correlation between the HRQoL of Hispanic women who are breast cancer survivors and the five significant factors.
In this study, differences in the association of the five significant factors on HRQoL across demographic and clinical subgroups of breast cancer survivors, including Hispanic ethnicity, age, race, education, region, marital status, smoking, insurance, poverty level, perceived health and mental status, BMI, employment, having Usual Source of Care (USC) and CCI, were identified. Despite the fact that the previous research has used different forms of questionnaires and scales, rather than the SF-12 MCS and SF-12 PCS, to measure HRQoL in cancer survivors, the findings were very similar to our finding that showed that the effect of age, census region, insurance type, perceived mental health status and CCI were associated with SF-12 MCS scores in breast cancer survivors [11][12][13][14]. Our study found that fair or poor perceived health or mental status were reported by 46.8% and 24.1% of survivors. These results correspond to a previous study that examined the effect of cancer on HRQoL which concluded that poor physical and mental HRQoL were reported by 24.5% and 10.1% of survivors, compared with 10.2% and 5.9% of adults without cancer. Even though this was a generalized study on all types of cancer, the adjusted mean mental and physical HRQoL scores were similar for breast cancer [11].
While we have identified various factors that negatively impact HRQoL, some factors that have a positive impact on HRQoL among breast cancer survivors include having psychosocial support [31]. It has been found that psychosocial support has had significant impact on the quality of life among cancer patients. For example, a previous study reported the importance of social integration by stating that, on average, socially isolated women were adversely affected by breast cancer. Socially isolated women presented with a lower role function, vitality, and physical function compared to more socially integrated women [31]. In the case of our breast cancer survivors in the Hispanic population, it was found in another research that, participating in community-based breast cancer awareness programs that are led by Hispanic/Latina women who were breast cancer survivors themselves has helped to significantly improve their survival and HRQoL [32]. This shows that cultural background, ethnicity, language and disease state played a role in positively impacting the HRQOL in this population.
In this study and any similar studies, the choice of outcome measure may have important effects on the results. HRQoL instruments are used based on the assumption that they are valid, reliable, and sensitive [33]. The SF-12 has been proven to be valid, reproducible and, useful in measuring the relationship between physical and mental health functioning and the social determinants of health [34]. While there are numerous strengths and limitations to this study, the form of measurement is very reliable.
Several limitations exist in this study. First, as this study is a crosssectional study design, it is unable to explain causation. Thus, the interpretation of the result is limited to the association between the given significant factors and HRQoL. Second, there is a possibility of a recall bias since medical conditions in MEPS are self-or proxy-reported and not verified by chart review. Third, the study used a generic HRQoL instrument. Even though generic measures cover a broad range of HRQoL dimensions in a single instrument, they are less responsive than specific tools that focus on a particular disease. Lastly, there is a possibility that the CCI could not detect more common comorbidities that might influence the results of this study. Despite having these limitations, this study is among the first to investigate on the HRQoL of Hispanic breast cancer survivors in the U.S.
In conclusion, this study presents data on the HRQoL of Hispanic breast cancer survivors in the U.S. It builds on previous research that examines the HRQoL as expressed through the SF-12 PCS and SF-12 MCS surveys, rather than other types of measurement. Overall, lower HRQoL were observed in those of ages >65, from the Midwest region, unmarried, smoking, uninsured, poor or low income, fair or poor perceived health and mental status, obese, unemployed, having USC, and a CCI score index of > 3. Interestingly, among the factors that most negatively impacted HRQoL among breast cancer survivors were smoking and perceived mental health status which are under personal health practices.
This research can lead to a better understanding of the factors that have been presented and that its findings used in contributing towards improving the quality of life in breast cancer patients in this population. In addition, it may be used as a guide in the implementation of clinical interventions and plans for survivorship care in improving the HRQoL of Hispanic breast cancer survivors.