Causal Effect Analysis of Demographic Concordance on Patient Perception of Physician Trust and Respect in an Emergency Care Setting

Objectives: Patient perceptions of physician trust and respect are important factors for patient satisfaction evaluations. We aim to determine the causal effect on patient-physician demographic concordance and patient perceptions of physician trust and respect in an emergency care setting. A near real-time patient satisfaction survey was sent via telephone to patients within 72 hours of discharge from an Emergency Department (ED). Patient-trust-physician (PTP) and physician-show-respect (PSR) scores were measured. Patient and physician demographics (age, gender, race, and ethnicity) were matched. We employed genetic matching to assign patients appropriately to the treatment (demographic concordance) and control (demographic discordance) groups. Causal effect was analyzed to determine the direct effect of patient-physician demographic concordance on PTP/PSR scores. Result: We enrolled 1815 patients. The treatment effect of patient-physician demographic concordance on patient perception of physician trust and respect ranged from -0.02 to -0.2 (p>0.05). In general, patient-physician demographic concordance has minimal effect on patient perceptions of physician trust and respect.


Introduction
Patient satisfaction is measured by after-care satisfaction surveys and has been used as a core metric to determine better quality patient-centered care. 1;2 Further examining patient satisfaction scores linked to these subjective questions revealed that it could be affected by both patient and provider demographics. 3;4 Results from McFarland and his colleagues showed that younger, white patients were predictive of a favorable healthcare rating, while non-English speaking patients were predictive of unfavorable healthcare satisfaction scores. 5;6 Moreover, a national cancer patient experience survey revealed that ethnic patients may report lower satisfaction and less positive experiences of their overall care, similar to the McFarland outcomes. 7 However, ndings are quite controversial in other studies. A retrospective study done at ED showed that elderly patients (>65 years old) had higher patient satisfaction than younger patients. 8 However, such ndings could be biased without analyzing healthcare provider demographics in relation to patient satisfaction.
In recent years, more studies have reported patient and physician demographic concordance affecting patient satisfaction. An HIV study conducted in New York city found that HIV patients rated their quality of healthcare higher if they are racially/ethnically concordant with their providers. 9 A primary care physician study found that race concordance seemed to be the primary predictor of perceived ethnic similarity, thus associated with higher ratings of provider trust, satisfactions, and intention to adhere to healthcare management. 10 Unfortunately, these ndings were not corroborated in other studies which showed less association between patient-physician demographic concordance and general healthcare satisfaction. 11;12 However, among all these studies, common association analytical methods such as correlation and regression were used with no direct causal effect reported between patient-physician demographic concordance and patient satisfaction.
Among patient satisfaction survey questions, some questions are asked to determine patient satisfaction with respect to their healthcare providers. Patient responses to these questions can be very subjective, particularly on ratings describing trust and respect between the physicians and the patients. Trust and respect could be highly variable across different demographics. Therefore, it is important to consider cross-cultural disparities between patients and healthcare providers. Such disparities could further affect patient-physician communications, thereby subsequently affect patient-centered care. 13 Therefore, in this study, we aim to determine patient-physician demographics affecting patient perceptions of provider trust and respect by using a causal effect methodology, a more accurate association analysis.

Study design and setting
This is a secondary data analysis from a quality improvement project. Data were collected prospectively from October 1, 2018 to September 31, 2019 but were analyzed retrospectively. This study was performed in an urban tertiary public funded hospital ED. The study ED has approximately 125,000 visits per year and is a level 1 trauma center, a comprehensive stroke center, and chest pain center. Due to secondary data analysis from a quality improvement project, approval for this study was waived by the local Institutional Review Board.

Study participants
We enrolled patients who had been discharged from the study ED and agreed to participate in a patient satisfaction survey delivered via their personal phones. We excluded patients who: 1) refused to participate in this survey; 2) did not know who their physicians were; 3) refused to answer whether they trusted their physicians' care; and 4) refused to answer whether their physicians showed respect to patients. In addition, physicians with less than 10 patient satisfaction surveys were excluded due to lack of statistical signi cance.

Study outcomes
Patient satisfaction surveys were measured as the study outcomes. We used the National Research Corporation (NRC) Picker patient satisfaction survey via telephone to recently discharged ED patients.
NRC patient satisfaction surveys is one of the most used patient satisfaction survey in the market. 14-16 NRC picker surveys have several different formats and can be delivered either by mail or telephone. All these surveys have been validated externally and used broadly across national EDs. There are 11 questions delivered to patients. In this study, two outcomes from the survey were measured. One is patient trust physicians' care (hereinafter referred to as "Patient-Trust-Physician", PTP) and the other is physician showing respect to patients (hereafter referred to as "Physician-Show-Respect", PSR). Both questions are answered using a 4-point Likert scale ranging from 1 to 4. A score of 1 is de ned as patients do not trust their physician or a physician does not show any respect to the patient. A score of 4 is de ned as patients de nitely trust physicians' care and physicians de nitely show respect to patients.

Study variables
We included both patient and ED physician general demographics including age, gender, race, and ethnicity. The time interval between patient discharge and their completed survey was calculated. Age was divided into three groups: 1) < 40 years old, 2) between 40 and 54 years old, inclusive (40-54 years old), and 3) equal to or greater than 55 years old (≥ 55 years old). Race was classi ed into three groups: 1) White, 2) African American, and 3) Others. "Others" includes Asian, American Indian or Alaska Native, Native Hawaiian or Other Paci c Islanders. Ethnicity was divided into Hispanic and non-Hispanic groups.

Causal effect analysis
We used a counterfactual approach to examine the causal effects of patient-provider demographic concordance on patient perception of physician trust and respect. The counterfactual approach is grounded on the counterfactual theories of causation, which explains the meaning of causal claims in terms of counterfactual conditionals of the form. 17;18 We denoted the outcome (i.e., perceived trust and respect by patients) for unit if the unit receives a treatment The treatments of particular interest included the patient-physician concordance on four demographical attributes: age, gender, race, and ethnicity. We denoted the potential outcome for unit in the control regime (e.g., demographic discordance). Hence, the treatment effect on unit can be derived by We employed genetic matching (GM) to assign patients appropriately to the treatment and control groups. 19 The absolute standardized mean differences were measured for all covariates before and after the matching to determine the matching performance. 19 We then calculated the estimated treatment effect and statistics to determine the causal effects after the matching with p value < 0.05 indicating the occurrence of such causal effect. Whereas p value > 0.05 indicates no causal effect exists based on statistical evidence. All analyses were performed using R package (x64 3.2.5) or STATA 14.2 software (College Station, TX) with p-value < 0.05 considered statistically signi cant.

Results
A total of 1815 patients and 33 ED providers were enrolled in this study. The median time interval from patient discharged from ED to their response to the survey was 67 hours (IQR 43, 104). A detail study ow diagram was shown in Supplemental Figure. The general demographics were different between patients and physicians. In patients, females were predominant, approximately 40% were 40-54 years old, and nearly 40% were Hispanic/Latino patients.
Whereas, in physicians, most were male (70%), White (73%), and non-Hispanic/Latino (94%) providers (See Table 1).   According to the plots, the value of absolute standardized mean differences for all the covariates decreased signi cantly after the GM, indicating a desirable balance was achieved and the treatment and control groups were prepared for a reliable causal analysis.
Tables 2 show the treatment effects of gender, age, race, and ethnicity concordance on patient perception of physician trust and respect. In all cases, the treatment effect is negative. However, only the treatment effect of age concordance on physician trust is statistically signi cant (p = 0.036). The rest of the estimated effects are not statistically signi cant.

Discussion
Physicians showing respect to patients and gaining patients trust during healthcare process are critical to establish patient-physician rapport, which subsequently affects patient healthcare outcomes. [20][21][22] However, patient perceptions of physician trust and respect are quite subjective and can be affected by multiple factors. Each potential factor can have interactions thus making routine association analyses (e.g., correlation, regression, etc.) less reliable. 23 Therefore, we performed a causal effect analysis in this study. We found that patient-physician demographics, in general, minimally affected patient perceptions of physician trust and respect. To the best of our knowledge, such direct causative effect analyses, speci cally on patient perceptions of physician trust and respect in related to patient-physician demographics, has not been reported before. Our ndings add extra evidence to the literature on demographics affecting patient-physician rapport. Such ndings might help future improving physician communication training during emergency care.
The study's strength is using causal effect analysis in an observational data setting. Such counterfactual analysis to causation for a general problem was reported before, but not widely used due to the strict model requirement. 24 Causal models are constructed separately to identify the causal relationship between each outcome and each treatment, it is ideal to measure cause effects on random samples. However, in an observational data setting, the baseline variables are almost never balanced across the treatment and control groups because the two groups are not ordinarily drawn from the same population. Therefore, matching -a procedure used to derive a balance of the baseline variables across treatment and control groups -must be conducted prior to the estimation of causal effects. This study employs genetic matching (GM) -a well-known matching method -to select patient-physician encounters from the observational data and assign them appropriately to the treatment and control groups. 19;25 Using such matched samples could thus determine the direct causal effects accurately.
Previous studies favored patient-physician demographic concordance in certain specialties (e.g., gynecology, family practice). 26;27 It can be inferred that patient-physician demographic concordance may affect communication patterns and perception of quality of care, that can further affect patient-physician relationship and health outcomes. However, such perceptions may not be duplicated in an emergent care setting. In an emergent care setting, patient-physician rapport is temporary and can be affected signi cantly by limited time and communication. At present, the in uence of ED physician demographics affecting patient centered care is not as well studied. A recent report of an ED study showed patientadvocator demographic concordance has no effect on the promotion of ED patients' HIV screening, though this is not strictly patient-provider related. 28 On the other hand, we are unclear of patient-physician age concordance having negative effect on patient perception of physician trust and respect in our study. A previous study reported that patients' views regarding age concordance were varied and unrelated to gender or racial/ethnic group. 27 Our future study will be particularly focused on the patient-physician age concordance in related to ED patient-centered care.

Conclusion
When patient near real-time satisfaction was performed in an emergent care setting, patient-physician demographic concordance has minimal causal effect on patient perceptions of physician trust and respect.

Limitation
Our study has its limitations. This is a retrospective observational study with secondary data analysis. Given the nature of this study design, patient selection bias, missing data, and inaccurate information inevitably exist. Although this study enrolled signi cant patient samples, our physician sample size is limited, which could potentially affect patient physician generic matching. Moreover, while this study was focused on PTP/PSR, overall patient satisfactions were not speci cally investigated, which might be hard to compare with other studies. Therefore, to accurately determine the role of patient-physician demographic concordance in related to patient-centered care, a larger multi-center prospective study is warranted for further validation.

Declarations
Ethics Approval and Consent to Participate: This study is waived for approval of documentation of the informed consent by University of North Texas Institutional Review Board due to a quality improvement project with retrospective data analysis.

Consent for publication: Not applicable
Availability of Data and Material: The data from this study are not available due to patient con dentiality reasons but are available upon request to the corresponding author.