Evaluation of the quality of safe dental services based on the perception of patients with the IPA approach: a powerful diagnostic tool for managers

Abstract

Background

In today’s competitive world, especially in critical situations, dental clinic managers seek to retain customers and allocate more market share. The importance-performance analysis (IPA) technique is a powerful diagnostic tool that helps managers identify fundamental deficiencies, establish priorities and provide insights into which service improvement areas managers should focus on. This study aimed to improve the quality of life of patients at the Alborz Dental Clinic based on their perception of safe services during the coronavirus pandemic using IPA.

Materials and methods

In this analytical cross-sectional study, 324 patients referred to at Alborz Dental Clinic from April 2021 to February 2022 were enrolled in the study through simple random sampling. The data collection tool used was a researcher-designed questionnaire based on the indicators of the quality improvement model and the guidelines of the Ministry of Health, Medical Education and Health of Iran regarding the provision of dental services in the context of COVID-19, the validity and reliability of which were measured. The gap analysis results and determination of areas of improvement were obtained using IPA. The data analysis was performed using SPSS26 and Excel software.

Results

The results of the paired ttest showed that the difference between importance and performance for all the research variables was significant (significance level less than 5%).The importance of the components exceeded their performance. The deepest gap among the five components of the model was related to accountability. IPA revealed that two variables, reliability and responsiveness, are placed in quadrant A, and three variables, tangibility, assurance, and empathy, are placed in quadrant B.

Conclusion

To improve the quality of safe services, dental clinic managers need to pay attention to the three dimensions of “tangibility”, “assurance” and “empathy” and plan and make decisions about the two dimensions of “reliability” and “responsiveness”.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-024-11955-4.

Introduction

Currently, the managers of dental clinics are not only seeking to maintain their patients and their market share but also trying to gain a greater share of the competitive market [1]. The highly competitive market conditions in the dental services industry have made recognizing, creating, and maintaining the quality of services one of the main concerns of healthcare providers in the field of dentistry [2]. Dental services are different from other medical services. Providing the simplest dental service requires effective communication between the dentist and the patient [3]. While providing the service, the patient may face attacks caused by underlying diseases such as asthma, which prolongs the duration of the service due to the implementation of special measures [4]. Dentistry is among the most expensive outpatient health care in Iran [5] and often lacks adequate insurance coverage [6]. This issue makes it difficult to attract and retain patients in dental clinics. The quality of health services is affected by patient opinions, attitudes, and perceptions [7], and patients make judgments based on their impressions after receiving services. They compare their expectations with their perceptions of the service they receive [8]. Service quality is a comparison of what the patient feels (expectations) with what she receives (perceptions) [9]. In other words, the difference between patients’ perceptions of services and received services indicates the level of patient satisfaction [10]. Ensuring patient satisfaction is vital to the continuation of economic activity at the clinic [11]. Managers play an important role in quality improvement [12]. Managers should carry out monitoring and control processes continuously to obtain periodic information on the level of patient satisfaction [13]. Timely and appropriate use of information in medical environments is necessary and mandatory [14]. It is essential to use effective measurement tools that enable not only the value of the service but also the importance given to each of the different attributes [13]. Due to limited resources, it is necessary to prioritize the areas that need quality improvement. Therefore, managers need a tool for prioritizing this topic. IPA is one of the most widely used tools in the field of identifying and prioritizing areas that need improvement in the service delivery process [15, 16]. The method of analyzing the IPA matrix is to measure the distance between expectations (importance) and perceptions (performance) around the studied phenomenon.This method is derived from one of the gap analysis methods.IPA is an effective tool for evaluating an organization’s competitive position, identifying opportunities for improvement, designing marketing strategies, and providing targeted services.This tool can provide effective suggestions for managers through the formation of a two-dimensional matrix in which the vertical axis shows the customers’ perception of the performance (quality) of each feature and the horizontal axis shows the importance of that feature in customers’ decision-making [17, 18]. This study was conducted to improve the quality of life of patients at the Alborz Dental Clinic through the use of the IPA technique.

Materials and methods

Study design and participants

The current research was an observational study and descriptive-analytical (cross-sectional) study. The statistical population of this research included all patients referred to the Alborz Dental Clinic from April 2021 to February 2022. This clinic was active only during the afternoon shift on business days in Iran (Saturday to Wednesday).

Sample size

According to Morgan’s table, the sample size was estimated to be 302 people, and considering the decrease of 10%, 332 questionnaires were distributed. Finally, 324 questionnaires were completed. If the patient was a child, his/her parents or companion completed the questionnaire. The questionnaires were distributed among the patients after they visited and received the required care.

Inclusion and exclusion criteria

The criteria for entering the study were “willingness and satisfaction of the participants” and “having minimum literacy”, and the criteria for excluding the study were “not completing more than 5% of the questionnaire”. The data collection tool used was a researcher’s questionnaire based on the indicators of the SERVQUAL quality improvement model and the instructions of the Ministry of Health regarding the provision of dental services during the COVID-19 epidemic.

Data collection tool

The data collection tool used was a researcher’s questionnaire based on the indicators of the SERVQUAL quality improvement model [19–23] and the instructions of the Ministry of Health regarding the provision of dental services during the COVID-19 epidemic (attached file) [24, 25].

This questionnaire consisted of two parts:

The first part gathered demographic characteristics of the studied patients, including sex, age, and marital status, level of education, service history, household income, employment status, number of visits to the clinic, and insurance coverage status. The second part included 30 questions aimed at evaluating five dimensions of service quality: physical and tangible dimensions (6 questions), reliability (6 questions), responsiveness (6 questions), assurance (6 questions), and empathy (6 questions). Patients’ expectations and perceptions were assessed using a five-point Likert scale, where 1 indicated strongly disagree and 5 indicated strongly agree. A total of 324 patients participated in the study. The questionnaire featured two types of questions: one measuring current perceptions and the other gauging desired expectations. Questionnaires were given face to face to those who were willing to complete the questionnaire. Those who had enough time completed the questionnaire in the presence of the researcher and the researcher answered their questions in person while completing the questionnaire and those who did not have time or wanted to complete the questionnaire at another time were given a questionnaire with the phone number and email of the project manager to answer each A possible question was given. Also, patients who preferred not to complete the questionnaire in person were invited to participate via phone or email.

Two methods, qualitative and quantitative, were used to assess the content validity of the designed questionnaire. In the qualitative approach, 10 specialists in management and quality improvement reviewed the questionnaire, evaluating its wording, item placement, and grammatical accuracy. Quantitatively, two metrics were calculated: the content validity ratio (CVR) and the content validity index (CVI). For the CVR, experts assessed the necessity of each item, with values above 0.62 deemed acceptable according to the Lavshe table. For the CVI, the relevance, clarity, and simplicity of each item were evaluated, with values exceeding 0.79 considered acceptable [26]. After determining content validity, 3 questions were removed from the questionnaire. To determine face validity in the qualitative section, the questionnaire was administered to 15 patients. A survey was also conducted to determine the participants’ level of difficulty in understanding the concepts, their degree of appropriateness and connection, and the degree of ambiguity and incorrect conclusions. Based on the comments and suggestions received from the participants, necessary changes were made to clarify the items. In addition, to determine the importance of the items and delete inappropriate items, the quantitative method of item impact was used. An impact score above 1.5 was considered acceptable.Therefor 2 questions were removed from the questionnaire.In order to reduce and eliminate inappropriate items and determine the importance of each item, the item impact method was used.

$$\text{Impact score}=\text{impotence*frequency}(\%)$$

The importance score of each item was considered between one (least important) and five (most important).

Then the frequency was calculated according to the number of people who gave each option a score.

Then check the result obtained from the sum of importance*frequency (%) if it was more than 1.5, that item was kept and if it was less than 1.5, that item was deleted [26].

To measure the reliability of the questionnaire, two methods, internal consistency and stability, were used. Internal consistency was measured using Cronbach’s alpha coefficient for a group of 30 patients. A Cronbach’s alpha equal to or greater than 0.7 was considered suitable. The Cronbach’s checked reliability alpha coefficient was calculated.

After obtaining permission from the ethics committee of the university, the researcher proceeded to distribute the questionnaires. The participants voluntarily participated in this study. Completing and returning the questionnaire was considered to indicate the satisfaction of the participants in the study. The questionnaire was completed anonymously, and the participants’ information was kept completely confidential. Several 325 questionnaires were distributed, and 324 questionnaires were completely completed and collected. The response rate was 99.6%.

Statistical analysis

After the data were collected, the analysis was performed using SPSS version 26. To describe the information, the researcher used frequency indices, and the average was used. Analysis of variance and paired t-test were used to test the hypotheses. The gap analysis results and determination of areas of improvement were obtained using IPA.This method has been used in many studies [17, 27–29]. Excel software was used to analyze the importance-performance matrix. The step-by-step method of IPA was as follows:

1. Identify Quality Characteristics: Determine the service quality characteristics that affect service quality.

2. Assess Importance and Performance: Determine the degree of importance and performance for each service quality characteristic (P = 1, 2… n and J = 1, 2… m). The importance and performance values for each characteristic (j-th attribute) are specified by decision-makers or clients using a Likert scale. These values range from 1 to 5, where 1 is the lowest and 5 is the highest.

3. Integrate Opinions: Use the geometric mean to combine the views of all decision-makers or customers, as suggested by Saati, to reflect the collective opinion. Quality of service is defined as the aggregate perspective of customers or experts.

$$\begin{array}{c}{b}_j=({\prod }_{i=1}^n{b}_{\mathit{jp}})_{}^{_{}^1\left./,_n^{}\right)}\\ \text{bj:degree of importancce}\end{array}$$

$$\begin{array}{c}{c}_j=({\prod }_{i=1}^n{c}_{\mathit{jp}})_{}^{_{}^1\left./,_n^{}\right)}\\ \text{cj: degree of performance}\end{array}$$

Therefore, each qualitative characteristic (jm) possesses both an importance level and a performance level.

• 4.Calculate the threshold value: To find the threshold value used in determining IPA matrix cells, compute it as the arithmetic mean between the significance threshold (μ_b) and the performance threshold (µ_c).

$${\mu }_b=\frac{{\sum }_{j=1}^m{b}_j}{m}$$

$${\mu }_c=\frac{{\sum }_{j=1}^m{c}_j}{m}$$

$m$ is the number of quality characteristics used to measure the quality of services.

• 5.Specify Relative Positions in IPA Matrix: Plot each service quality characteristic in the IPA matrix to determine its relative position in one of the four quadrants: “Keep up the good work,” “Focus here,” “Waste of resources,” or “Low priority.” The relative position of each service quality characteristic is specified in the IPA matrix. (Fig. 1).

Fig. 1.

IPA matrix

The IPA matrix divides service quality characteristics into four quadrants:

• Quadrant B (Keep up the good work): High importance and high performance.

• Quadrant A (Focus here): High importance but low performance.

• Quadrant D (Waste of resources): Low importance and low performance.

• Quadrant C (Low priority): Low importance but high performance.

• 6.Discover Customer Priorities: Calculate the weight of each qualitative characteristic based on the difference between its importance and performance values, normalized to prioritize features needing improvement. According to Wu et al. [30] the difference between the significance and performance values of the j-th characteristic, multiplied by its importance value, indicates the weight of that characteristic. This weight is denoted as owj.

$${\mathit{OW}}_j=\left|\left(b_j,-,c_j\right),\times ,b_j\right|$$

To enhance accessibility of the analysis, we normalize it in the following manner:

$$\begin{array}{cc}{\text{SW}}_j=\frac{{\mathit{OW}}_j}{{\sum }_{j=1}^m{\mathit{OW}}_j},& 0\le {\mathit{SW}}_j\le 1-,{\sum }_{j=1}^m{\mathit{SW}}_j=1\end{array}$$

Features with a higher SW_j should be prioritized for improvement.

Ethical consideration

The ethics committee of Alborz University of Medicine approved the present study.

Sciences dated 2021–04–26, with the code IR.ABZUMS.REC.1400.028.In this research, all ethical considerations were considered. The patients voluntarily participated in this study.The method and objectives of the study were explained at the beginning of the questionnaire,and the participants were asked to be willing to complete the questionnaire.Patients who answered the questions of the questionnaire and returned it were considered to provide consent to participate in the study.The questionnaires were completed anonymously.Patients were assured that the information would remain confidential.

Results

The results showed that most of the studied patients were female (70.4%), single (50.3%), were under 30 years of age (55.6%), had an income of 5–10 million (46.3), had an academic degree (73.76%), had an employment status of 37.3, had a history of three or more dental visits at this clinic (44.1), had medical insurance coverage (73.1%) and had no supplementary insurance (70.4%) (Table 1).

Table 1.

Demographic characteristics of the studied patients (n = 324)

Variable	Group	Frequency	Percent
Sex	male	96	29.6
	female	228	70.4
Age	< 30	180	55.6
	30–40	73	22.5
	40–50	40	12.3
	50–60	22	6.8
	Missing System	9	2.8
Marital status	Single	163	50.3
	Married	153	47.2
	Total	316	97.5
	Missing System	8	2.5
Education level	Reading and writing	39	12.0
	Diploma	46	14.2
	Associate degree	88	27.2
	Bachelor’s degree	102	31.5
	Masters	18	5.6
	Ph.D	31	9.6
Income job	< < 5 Million	54	16.7
	5–10 Million	150	46.3
	10–15 Million	105	32.4
	> 15 Million	13	4.0
	Missing System	2	0.6
Employment status	Public	121	37.3
	Private	47	14.5
	self-administered	51	15.7
	Retired	28	8.6
	Housekeeper	45	13.9
	unemployed	13	4.0
	Missing System	19	5.9
Dental visit history in this clinic	Once	104	32.1
	twice	77	23.8
	Three times and more	143	44.1
Insurance status	Yes	237	73.1
	No	87	26.9
	Total	324	100.0
Supplementary insurance	Yes	83	25.6
	No	228	70.4
	Missing System	13	4.0
Total		324	100.0

Table 2 shows the descriptive statistics of the research variables on performance status (existing status) and importance (desired status) and the results of paired t-test.

Table 2.

The results of paired t-test to examine the gap between importance and performance

Variables	Performance		Importance		Paired-Sample T-Test
	Mean	SD*	Mean	SD	Gap	T-Value	P-Value
Tangibility	3.857	0.699	4.429	0.661	0.572	10.907	0.000
Reliability	3.506	1.025	4.420	0.731	0.914	13.251	0.000
Responsiveness	3.499	0.988	4.508	0.668	1.010	16.386	0.000
Assurance	4.008	0.725	4.515	0.728	0.507	14.549	0.000
Empathy	3.860	0.881	4.486	0.714	0.626	10.044	0.000
Quality	3.746	0.752	4.472	0.671	0.726	14.452	0.000

^*SD Standard deviation

H0: The difference between the scores of expectations (optimal situation) and perceptions (current situation) is equal to zero.

H1: The difference between the scores for expectations (optimal situation) and perceptions (current situation) is significantly different from zero.

The results of the paired t test showed that the gap between importance and performance for all the research variables was significant (significance level less than 5%), that there was a significant difference between importance and performance, and that the importance of the components was greater than their performance. The largest gap among the 5 components of the model was related to responsiveness (Table 2).

The Cartesian diagram is a diagram showing the importance and performance of the quality of dental services provided by the service provider. The Cartesian diagram can be seen in Fig. 2.

Fig. 2.

Cartesian diagram showing the quality of dental services (four quadrants of the IPA matrix)

Figure 2 provides a description concerning the quality of dental services viewed from the importance desired by the respondent or the service customers concerning the performance that occurred in the field. This diagram attributes the quality of dental services (four quadrants of the importance-performance matrix). In this diagram, the Y-axis indicates the importance dimension, and the X-axis indicates the performance dimension. The assessed aspects can be seen from the four quadrants, namely, quadrants A, B, C, and D.

The importance-performance matrix diagram shows the importance and performance of the quality of dental services provided by the service provider, and the calculation methods are shown in Tables 3 and 4.

Table 3.

Importance of critical indicators

critical indicators	bj	Cj
Tangibility	4.370	3.790
Reliability	4.344	3.347
Responsiveness	4.451	3.341
Assurance	4.438	3.935
Empathy	4.414	3.758

${\mu }_b=4.403,{\mu }_c=3.634$ 

Table 4.

Calculations for Owj and Swj

Component	Owj	Swj	Priority	Quarter of the matrix
Tangibility	2.5	0.150	4	B
Reliability	4.3	0.256	2	A
Responsiveness	4.9	0.292	1	A
Assurance	2.2	0.132	5	B
Empathy	2.9	0.171	3	B

swj Subjective weight

owj objective weight

Discussion

The aim of this study was to evaluate the service quality of the dental clinic affiliated with the ALBORZ University of Medical Sciences. The Alborz Dental Clinic is a government institution affiliated with the Alborz University of Medical Sciences and Health Services and is located in the Alborz Province, one of the most densely populated provinces in Iran. This province is one of the neighboring provinces of Tehran (the capital of Iran) [31–33]. The geographical location of this clinic has made it more competitive to attract and retain customers. Managers face serious challenges in maintaining their market share and allocating more shares from the competitive market.

The findings of this research showed that there was a significant difference between the importance (ideal situation) and performance (existing situation) in this clinic; that is, the expectations of patients referring to this clinic in all aspects of quality were greater than their perception of the services they had received. Our findings are in accordance with those of previous studies [34, 35]. Patients at this clinic are expected to receive higher-quality services. The most unfulfilled expectation was related to the Responsiveness and Reliability dimensions. Comparing the findings of this research with the findings of other countries in the world showed that in countries like Greece [36], the biggest gap in the quality of dental health care in dental clinics is related to the dimension of responsiveness, and in Indonesia [37, 38] and Brazil [39], it is related to the dimension of reliability.From the patients’ point of view, the performance of this clinic regarding the availability of service providers, the provision of accurate and emergency services (responsiveness dimension), and the ability to provide safe and efficient services by service providers (reliability dimension) did not meet their expectations. Perhaps the cause of these findings can be attributed to the type of affiliation of the clinic (government) and the duration of the study (coronavirus pandemic era). During the coronavirus pandemic, government organizations had to follow the restrictions set by the government (holiday). A lack of planning by managers to address critical situations could also explain the lack of clinical response to emergency services for patients.The implementation of the rotating shift program by the managers made it impossible for the patient to be visited again by the same dentist in the future, leading to low-quality responses. Additionally, during this period, the dentists and all the health treatment personnel at the clinic had not completed a training course in the fields of safety and familiarity with health protocols. Only the protocols were communicated. Managers could design educational interventions to change the behavior of employees by holding virtual workshops, webinars, and brainstorming sessions, in addition to justifying and training service providers on their perception of the need to explain simple and understandable language to patients. Regarding health protocols and handling patients’ complaints regarding noncompliance with protocols. The goal of all educational interventions is to change behavior, not just to set goals [40]. Additionally, the restriction of the incidence of this disease has affected economic conditions and the monthly income of patients. Therefore, the patients expected that the amount and manner of their payments would decrease significantly during this period. However, policymakers have emphasized reducing perceived costs to induce safe behavioral intentions [41]. However, the clinic managers had not taken any action regarding the planning and organization of this issue. However, managers are advised to make better decisions to improve the quality of medical and healthcare services [42]. Therefore, the services provided may have been appropriate and without mistakes, but due to the inability to pay the costs, the patient’s perception of reliability decreased. Importance Performance Analysis (IPA) revealed that two variables, reliability and responsiveness, were associated with Quadrant A.Considering that the importance of these two factors from the patients’ point of view was very high, the performance of the complex in this field could not meet the expectations of the patients. Therefore, it is necessary for clinical managers to focus on these two factors and prioritize them for improvement. Therefore, increasing clinical performance can increase patient satisfaction. The findings of this research were in accordance with the findings of Adebayo et al.’s study. They showed that patients in a Nigerian public dental clinic need to pay more attention to the dimension of “reliability” to improve patient perceptions [43]. Additionally, the results of Akbar et al.’s study (2019) showed that the reliability dimension has a significant effect on the quality of dental clinic services [44]. Dewi et al. (2011) found two factors, reliability and responsiveness, to be very effective at increasing patient satisfaction, and they considered paying attention to service delivery time and providing explanations in simple and comprehensible language to be important priorities for managers’ decision-making [37]. Doctors can provide additional explanations to patients about their condition, and treatment plans can increase patient satisfaction [45]. In addition, IPA showed three dimensions, namely, Tangibility, Assurance, and Empathy, in quadrant B. These three factors were the main strengths of the clinic and are considered its competitive advantage; therefore, they should be preserved and given more attention to managers than before. These factors are not only very important from the point of view of patients but also strongly important in the clinic. According to the findings of this research, it is recommended that clinic managers maintain their actions in the field of three dimensions—tangible, assurance, and empathy—to improve the quality of safe services. According to the patients, this clinic had adequate physical space and equipment during the coronavirus pandemic. During this time, a competent treatment team provided services (with the ability to instill a sense of trust and confidence in patients), and the treatment team understood the patients and treated them respectfully and in accordance with the spirit of each patient. The findings of Mohebifar et al. [46] and Bushov and Gray [47] are also in line with the results of this research. These researchers stated that the environment and physical evidence, rather than the actual service, mainly influence patients’ perceptions of quality. Javed and colleagues also consider quality assurance a requirement for achieving and maintaining good performance [48]. Sherman and Kramer have cited empathy as a “core competency” for dentists Jones et al. believes that a lack of empathy reduces patient satisfaction [49]. The results showed that none of the service quality dimensions of this dental clinic were included in quadrant C [50]. In other words, all patients visiting this clinic expected to receive quality and safe services, and all aspects of quality were highly important. This finding confirms that although the patients’ expectations are more than their perceptions of the services received, this clinic has not performed poorly in any of the quality dimensions. In addition, the obtained results showed that none of the service quality dimensions of this dental clinic were placed in quadrant D. In explaining this finding, it can be said that the managers of this clinic use limited resources in the best way and do not waste these resources in any way. The results of this study were consistent with the results of Tileng et al. [51]. Perhaps the reason for this finding can be expressed in this way that in this clinic, the principle that “the attitude of patients should be checked continuously” and “the responsibility of improving the quality level of the clinic should be assigned to the clinic management”[52] was observed. However, patient safety is a collective responsibility that requires the commitment and cooperation of all stakeholders, from healthcare professionals to administrators and patients themselves.It is suggested that patient safety in dental clinics should be considered as a manager’s priority in order to reduce risks and improve treatment results, thus strengthening trust and confidence among patients [53].

Limitations

Several limitations of this research include the cross-sectional nature of the study, which involved examining only the views of patients regarding the quality of dental services; moreover, it is necessary to examine the views of other stakeholders, including dentists, managers, and other service providers in the clinic.

Conclusion

This research showed that the IPA could be a valuable diagnostic tool for supporting management decisions in dental clinics. This tool can help the decision-making of dental clinic managers by setting priorities and formulating improvement strategies. Considering that visitors to dental clinics have little satisfaction with “reliability” or “responsiveness”, it is necessary for clinic managers to consider these two dimensions as the two main priorities in quality improvement decisions. In other words, by planning and organizing to “provide services in a safe and secure manner” and “fulfill the clinic’s obligations in the field of providing services to clients”, improve patients’ satisfaction in the field of “reliability” and by “obtaining opinions, suggestions and criticisms” “helping clients and providing services on time” to increase patients’ satisfaction in terms of responsiveness. The quality of service delivery does not include only the provision of technical services. It should also be noted that providing and maintaining the quality of services in the organization in all aspects of quality improvement does not cost much. For example, delivering and maintaining the “reliability” dimension can be achieved by fulfilling all the promises the clinic makes to clients. Additionally, “responsiveness” is achieved by providing correct, timely, and correct services to appropriate patients and responding without interruption of patients’ suggestions and comments.

Abbreviations

IPA

Importance-performance analysis

Sw_j

Subjective weight

Ow_j

Objective weight

SD

Standard deviation

Authors’ contributions

All authors(L. K-A. & J.M.) contributed equally to preparing all parts of the research. Both authors read and approved the final version of the manuscript.

Funding

This study was funded by the Research Deputy of Alborz University of Medical Sciences. The funding body had no role in the design of the study.

Data availability

No datasets were generated or analysed during the current study.

Declarations

Ethics approval and consent to participate

The study was approved by the Ethics Committee of Alborz University of Medical Sciences (code IR.ABZUMS.REC.1400.028). All methods were carried out in accordance with relevant guidelines and regulations (Declaration of Helsinki). All participants were informed of the aims of the study. In addition, the top part of the questionnaire states, “Participation in this research is voluntary. Please complete the questionnaire if you are willing and satisfied”, but this phrase was also expressed by the researchers when distributing the questionnaires. The questionnaire was subsequently given to the patients who verbally expressed their desire and satisfaction. Even the patients had the option not to complete the questionnaire after seeing the questions if they did not want to. Informed consent was obtained from all participants.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.