Relationship between the characteristics of Japanese physicians involved in medical care for older adults and their approaches to treating older patients with multimorbidity

One countermeasure against the increasing prevalence of multimorbidity is the need to provide clinical education and training that considers the characteristics of physicians. We conducted a questionnaire survey to determine the relationship between physicians’ characteristics and their approach to treating older patients with multimorbidity. A total of 3300 geriatric specialists and primary care specialists in Japan were enrolled. A 4-point Likert scale was used to score the following items: difficult diseases (43 items), difficult patient backgrounds (14 items), important clinical factors (32 items), and important clinical management (32 items). Exploratory factor analysis was performed to examine the constructs in each of the scales Diseases, Backgrounds, Clinical Factors, and Clinical Management, and group comparisons by physician characteristics were conducted. A total of 778 respondents were included in the analysis. Six factors for Diseases, two factors for Patient Background, four factors for Clinical Factors, and two factors for Clinical Management were explored as patterns. Group comparison between mean scores for each factor and the characteristics of responding physicians showed statistically significant differences in at least one factor for all patterns in terms of years of experience as a physician (26 years or less, 27 years or more), the clinical setting (providing or not providing home medical care), and sex (male or female). Our results suggest a need for clinical education and training that takes into account not only physicians’ experience and clinical setting, but also their sex.


Introduction
Multimorbidity, defined as the coexistence of multiple chronic diseases in a single patient, presents a significant challenge to health care systems worldwide [1,2].Multimorbidity leads to various outcomes, including increased polypharmacy, reduced quality of life (QOL), higher health care resource utilization, and mortality [3][4][5][6][7].Efforts to enhance the quality of care have focused on clinical education and training, but their effectiveness has been limited [8][9][10][11].To enhance education and training in multimorbidity care, it is crucial to understand the specific challenges faced by physicians and the key aspects of management that physicians prioritize.
In Europe and the United States, geriatricians and primary care physicians (e.g., general practitioners in the United Kingdom) play central roles in managing older patients [12][13][14].Although it is unclear whether practice guidelines developed in Europe and the United States can be adapted to Japan's health care system, geriatricians and primary care physicians in Japan are expected to be involved in the care of older patients with multimorbidity.We have previously examined the challenges faced by geriatricians and primary care physicians in Japan when treating older patients with multimorbidity, along with the emphasized management strategies, highlighting both similarities and differences between them [15].However, the relationship remains unclear between physicians' approaches to treating multimorbidity in older patients, as well as physician characteristics such as years of experience or the clinical setting in Japan.In Europe and the United States, various consultations for older patients with multimorbidity are provided in clinics, and the importance of generalists, such as general practitioners and geriatricians, as attending physicians in hospital wards has been highlighted.However, the relationship between the physician's sex and experience as well as their approaches to treating multimorbidity in older patients is unclear [16,17].Understanding physicians' characteristics is vital for tailoring strategies and clinical education with respect to multimorbidity.
Hence, we conducted a survey to elucidate the relationship between the characteristics of geriatricians and primary care physicians and their approach to treating older patients with multimorbidity.

Study population
Between June and July 2022, an unregistered postal survey was conducted among 3300 participants, including 1650, the total number of geriatric specialists (G specialists) from the Japan Geriatric Society and 1650 primary care specialists (PC specialists) randomly selected from among 1091, the total number of family medicine specialists and 5435, the total number of primary care physicians certified by the Japanese Primary Care Association (JPCA).

Questionnaire
The questionnaire comprised two parts: respondents' practice approach to multimorbidity and characteristics of the respondents.The practice model for treating older patients with multimorbidity was constructed based on previous studies, addressing difficult diseases/backgrounds and important clinical factors/clinical management among physicians [12-14, 16, 18-20].The questionnaire was labeled "G" for G specialists and "P" for JPCA specialists.
For questions regarding their approach to treating older patients with multimorbidity, participants rated difficulties in treating diseases (43 items, Appendix 1 in S1 Appendix), patient backgrounds (14 items, Appendix 2 in S1 Appendix), important clinical factors (32 items, Appendix 3 in S1 Appendix), and important clinical management strategies (19 items, Appendix 4 in S1 Appendix) using a Likert scale from 1 ("not at all") to 4 ("very much").Respondents also indicated their views regarding the difficulty in treating multimorbidity in older patients and the importance of general practice guidelines, also using a Likert scale.
As for respondents' characteristics, participants provided information on their sex, age, years and months of experience as a physician, type of facility, clinical setting, municipality population size, and frequency of treating patients in specific age groups (65-75, 75-90, �90 years).They also disclosed their qualifications.

Ethical considerations
This study received approval from the Ethical Review Committee of the Maruki Memorial Medical and Social Welfare Center, the first author's previous institution (No. 37).The questionnaire cover page outlined the survey's purpose, privacy protection, and provided contact information.Consent was inferred upon participant completion of the questionnaire.

Statistical analysis
Regarding treating older patients with multimorbidity, a 4-point Likert scale was used to assess items in the categories of "Diseases," "Backgrounds," "Clinical Factors," and "Clinical Management," with 1 denoting "not at all" and 4 indicating "very much."Mean and standard deviation were calculated.Respondents indicating "sometimes" or "often" were grouped together as "yes" in terms of having difficulty treating older patients with multimorbidity and the importance of referring to general practice guidelines; those who responded "not often" or "never" were grouped as "no." Backgrounds of respondents were categorized into a "clinic group" (those working in a clinic with or without beds) or "hospital group" (those working in a hospital with <200 or >200 beds or university hospital).Population size was divided into "under 100,000" and "over 100,000."The frequency of treating certain age groups (65-75, 75-90, �90 years) was classified as "low frequency" (never or not often) or "high frequency" (sometimes or often).
Next, we explored constructs in the approach to treating older patients with multimorbidity.The items in the Diseases, Backgrounds, Clinical Factors, and Clinical Management scales were considered to be very diverse and interrelated; we considered that it would be useful to explore factors that commonly influence each item by examining the correlation between them.We reconstructed the scale at the smallest unit and then clarified the relationships with physicians' characteristics.We conducted exploratory factor analysis using the maximum likelihood method and promax rotation to examine the constructs in each of the scales Diseases, Backgrounds, Clinical Factors, and Clinical Management in the approach to treating older patients with multimorbidity.First, an initial analysis was conducted using the number of factors with an eigenvalue of 1 in a scree plot; factor loadings greater than 0.40 were considered meaningful and used as a criterion for item selection [21].Variables with factor loadings less than 0.4 or those included in two or more factors were then deleted [21].The second and third rounds of analysis were conducted, adopting the factors that could be interpreted as the final model: "Disease patterns", "Background patterns, " "Clinical factor patterns", and "Clinical management patterns".Cronbach's alpha coefficients were calculated for each scale overall and for each factor to verify internal consistency.
As a final analysis, group comparison of mean scores for each factor in each scale and characteristics of respondents was conducted.The mean scores for each of the factors Diseases, Backgrounds, Clinical Factors, Clinical Management were analyzed according to the following groups: sex, years of physician experience (below median, above median), practice facility (clinic, hospital), clinical setting (ward practice, home medical care, practice in a nursing home), municipality population (under 100,000, over 100,000), frequency of practice by age group (low-frequency group, high-frequency group), and general practice guidelines (emphasis, non-emphasis).Student t-tests were conducted for comparison, using SAS version 9.3 (SAS Institute Inc. Cary, NC, USA).

Results
A total of 836 questionnaires were received (25.3% response rate), with 439 from G specialists (26.6% response rate) and 397 from JPCA (PC) specialists (24.06% response rate).In group G, four respondents either indicated that they lacked geriatric specialization or left their response blank, even though they were eligible for geriatric specialty certification.Additionally, in the PC group, 11 respondents either did not have family medicine certification or primary care certification or left their response blank, despite being eligible for family medicine or primary care certification.Thus, questionnaires from 15 respondents were excluded.To focus on physicians reporting difficulty in treating multimorbidity among older patients with a specific disease, we excluded 14 respondents who answered "not at all" to the question of whether they have difficulty treating older patients with multimorbidity and 29 questionnaires with responses missing for all items on treating difficult diseases.Finally, 778 cases were included in the analysis.
As shown in Table 1, in total, 629 (81.7%) physicians were men and 141 (18.3%) were women, with mean age 53.5±12.1 years.The mean length of career as a physician was 27.8 ±11.9 years, with a median of 27 years.As for age, 368 respondents were 26 years old or younger and 401 were 27 years old or older.In terms of facilities, 238 (32.9%) respondents worked in a clinic and 485 (67.1%) in a hospital; 734 (94.3%) respondents had an outpatient practice, 300 (38.6%) worked in home medical care, 215 (27.6%) practiced in nursing homes, and 413 (53.1%) had a ward practice.Regarding the population size of the municipalities where physicians treated patients, 207 (27.2%) worked in municipalities with fewer than 100,000 residents and 554 (72.8%) were from municipalities with more than 100,000.Regarding the frequency of treating patients aged 65 to 75 years, 4 (0.5%) physicians reported low frequency and 771 (99.5%) reported high frequency; for patients aged 75 to 90 years, three (0.4%) physicians reported low frequency and 774 (99.6%) reported high frequency; and for treating patients over 90 years old, 39 (5.0%) physicians reported low frequency and 739 (95.0%) reported high frequency.Regarding qualifications, 505 (64.9%) physicians stated that they were a fellow of the Japanese Society of Internal Medicine, 396 (50.9%) were board-certified members of the Japanese Society of Internal Medicine, 415 (53.3%) were geriatric specialists, 369 (47.4%) were primary care-certified physicians, 113 (14.5%) were family medicine specialists, and 34 (4.4%) physicians were specialists in home medical care.

Descriptive statistics
Tables 2 to 5 show descriptive statistics for difficult diseases, difficult backgrounds, clinical factors, and clinical management, respectively.As for referring to general practice guidelines, 33 physicians reported "sometimes," 582 answered "often," 139 stated "not often," and seven physicians said they "never" referred to the guidelines.Thus, 615 respondents were categorized in the "yes" group and 146 were in the "no" group.

The constructs in the approach to treating older patients with multimorbidity
Six factors were explored regarding "Disease patterns" and the overall Cronbach's alpha coefficient was 0.937 (Table 6).Factor 1 encompassed seven items including congestive heart failure, diabetes mellitus (with complications), and chronic kidney disease.This was termed "cardiovascular disease with diabetes mellitus" (vascular), indicating patients with advanced atherosclerosis, a history of smoking, and diabetes as underlying conditions.Factor 2 included five items involving lifestyle-related diseases like hypertension, diabetes mellitus (without complications), dyslipidemia, and thyroid disease.This was labeled "outpatient internal medicine diseases" (outpatient) to indicate continual practice in a general internal medicine outpatient clinic.Factor 3 comprised three items covering cerebrovascular diseases and neurological intractable diseases, labeled "neurological disease" (neurological).Factor 4 comprised five items including solid tumors, cancer metastasis, lymphoma, leukemia, and AIDS.This was designated "malignant tumor, hematologic diseases, and AIDS" (malignancy).Factor 5 consisted of 13 items encompassing dementia, benign prostatic hyperplasia, osteoarthritis, and others.This factor included pathologies of various organs associated with aging and was denoted "geriatric syndrome" (geriatric).Factor 6 included four items related to visual impairment, cataracts, and dental problems and was termed "ophthalmologic and dental" (ophthal).Two factors were explored regarding "Background patterns" and the overall Cronbach's alpha was 0.881 (Table 7).The first factor comprised six items including social and psychological issues, named "complex background" (complex).The second factor involved five items, such as challenges in collecting clinical information and collaborating with specialists of organs or areas, denoted "difficulty in collecting clinical information and cooperation" (lack of information and cooperation).
Four factors were explored for "Clinical factor patterns" and the overall Cronbach's alpha coefficient was 0.844 (Table 8).Factor 1 encompassed six items regarding bedridden activities of daily living (ADL), nutrition, and psychiatric complications, termed "low ADL/nutrition, and psychiatric problems" (low ADL and psychiatry).Factor 2 comprised three items related to therapies affecting QOL, termed "treatment-induced QOL decrease" (QOL decrease).Factor 3 comprised three items concerning treatment burden and limited daily life support, denoted "treatment burden and difficulties in daily life" (burden).Factor 4 comprised three items including age, number of medical institutions, and coexisting diseases, termed "age and multiple medical conditions" (multiple medical).Two factors were explored regarding "Clinical management patterns" and the overall Cronbach's alpha coefficient was 0.78 (Table 9).The first factor included three items on re-evaluating treatment, named "re-establishment of treatment goals" (re-establishment).The second factor encompassed five items including patient preferences and collaboration among professions, termed "confirmation of clinical preference and collaboration among multiple professions" (confirmation and collaboration).

Comparison of mean scores for each factor of each scale and characteristics of respondents
The S1  For sex, in "Disease patterns", men scored higher in "malignancy."For "Background patterns," women scored higher in "lack of information and cooperation."In "Clinical factor patterns", women had higher scores in "QOL decrease" and "burden."In "Clinical management patterns," women scored higher in "re-establishment" and "confirmation and collaboration." Regarding years of experience as a physician, in "Disease patterns," older physicians scored higher in "malignancy" and "ophthal."For "Background patterns," younger physicians scored higher in "complex" and "lack of information and cooperation."In "Clinical factor patterns," younger physicians had higher scores for "burden."In "Clinical management patterns," younger physicians scored higher in "re-establishment" and "confirmation and collaboration." As for facilities, hospital physicians scored higher in "complex" than clinic physicians in the same category.In terms of clinical setting, in "Disease patterns," the group with home medical care "not provided" scored higher in "neurological," "malignancy," and "geriatric."For "complex" in "Background patterns," the group reporting ward practice "provided" scored higher than "not provided" and the group reporting home medical care "not provided" scored higher than "provided".In "Clinical factor patterns, " the group with home medical care "not provided" had higher scores in "burden."In "Clinical management patterns," the group reporting home medical care "provided" scored higher in "confirmation and collaboration."No differences were found between the "not provided" and "provided" groups in nursing homes.
Regarding population size, the mean value of "geriatric" in "Disease patterns" was significantly higher in the "over 100,000" group.In the frequency of practice among patients aged 65-74 years and 75-90 years, there were no significant differences between the low-frequency group and high-frequency group.As for the frequency of practice among patients aged 90 years or older, mean values for the high-frequency group were significantly higher for "burden" in "Clinical factor patterns" and "confirmation and collaboration" in "Clinical management patterns."For general practice guidelines, the non-emphasis group was significantly higher for "burden" in "Clinical factor patterns."

Discussion
In this study, we examined the relationship between difficult disease/patient background, important clinical factors/management and physician characteristics when treating older patients with multimorbidity.
Regarding sex, men perceived more difficulty in treating "malignancy "in "Disease patterns" than women.Women reported greater difficulty than men in treating "geriatric" in "Disease patterns" and "lack of information and cooperation" in "Background patterns."These may be related to the fact that women are more critical in their self-evaluation than men [22].Additionally, women prioritized "QOL decrease" and "burden" in "Clinical factors pattern," along with "re-establishment" and "confirmation and collaboration" in "Clinical management patterns," more so than men.A study comparing male and female physicians revealed lower 30-day mortality and re-admission rates in older patients (65 years and older) treated by female physicians for internal medicine-related conditions [23].Further research on the distinct approaches of female and male physicians in managing older patients with multimorbidity is encouraged.
Physicians with less experience prioritized "burden" in "Clinical factor patterns" and "reestablishment" and "confirmation and collaboration" in "Clinical management patterns" more frequently than their counterparts with greater experience.These aspects align with guidelines such as those of the National Institute for Health and Care Excellence, but variations in educational exposure might also play a role.In terms of physician experience and practice style, it was observed that more experienced physicians tended to show lower adherence to diagnostic criteria [24].Whereas this is not specific to multimorbidity practice, it underscores the importance of ongoing education for seasoned physicians regarding the focal points of multimorbidity care.
Concerning facilities, "complex" in "Background patterns" was a greater concern among physicians in hospitals than those in clinics.It has been pointed out that complex backgrounds are one of the central issues in multimorbidity practice [25].To address this complexity, the medical treatment approach should consider the type of facility, whether a clinic or a hospital.Concerning the clinical setting, those involved in ward practice found "complex" factors in "Background patterns" more challenging than those not in a ward practice.Variations in disease patterns are linked to differences in re-admission and in-hospital mortality rates [26].Further research into medical treatment content and styles for multimorbidity in older patients is advisable.
Physicians involved in home medical care were less likely to experience difficulties in managing "neurological," "malignancy," and "geriatric" in "Disease patterns."In this study, "geriatric" includes dementia.It has been reported that the coexistence of dementia in diabetes mellitus is a factor that makes it difficult to introduce home medical care [27].In home health care, patients with severe dementia and diabetes are difficult to refer, and this may have affected the results.This may need to be discussed when treating older patients with multimorbidity, as well as the presence or absence of medical procedures such as ventilators [28].Regarding "neurological," it is clear that ventilator-dependent patients, especially those with intractable neurological diseases, require specialized attention [28].
"Complex" in "Background patterns" was found to be less difficult for the group involved in home medical care.Home care patients are considered more complex than ward patients owing to the number of comorbidities and comorbid cognitive dysfunction [29,30].Clarification is needed regarding the background of visiting physicians who do not consider complex backgrounds to be difficult to treat.It is also possible that physicians who do not consider complex backgrounds difficult to treat may be providing home medical care.Additionally, "burden" in "Clinical factor patterns" was found to be more important when home medical care was provided.Patients with multimorbidity were reported to perceive a treatment burden in terms of medication and impact on daily life (including involvement of caregivers) [31].It is possible that physicians who provide home medical care are more likely to perceive the impact on their daily lives and recognize the burden of treatment.Furthermore, physicians providing home medical care emphasized "confirmation and collaboration" in "Clinical management patterns" more than their counterparts in other clinical settings.Whereas multidisciplinary collaboration has limited effects on managing multimorbidity, there are reports suggesting that home rehabilitation therapy led by professionals can improve functional outcomes for patients with multimorbidity; this warrants further research [32,33].
We observed that the group that did not prioritize general practice guidelines placed greater emphasis on "burden" in "Clinical factor patterns."These results suggest that general practice guidelines should be emphasized in medical care, but it is also necessary to educate physicians about the importance of "burden" as a patient outcome.
Limitations of this study include the following.First, the present responses may differ from actual practice, and we were unable to comprehensively examine the practice of multimorbidity in older patients.Thus, there may be unmeasured items and potential confounders.Furthermore, this study was a cross-sectional survey, and we only examined inter-relationships at the time of the survey.In the future, qualitative methods such as interviews and clinical scenarios can be used to examine multimorbidity treatment in more detail.
Second, the Cronbach's alpha coefficients for the four patterns identified in exploratory factor analysis were above a certain level, suggesting that internal consistency was ensured, to some extent.The validity of this information is limited, although it is interesting to infer the thought process of physicians in actual clinical practice regarding the treatment of older patients with multimorbidity.It is important to note that the patterns of diseases in multimorbidity can substantially impact patient outcomes, affecting ADL and health-related QOL [4,5,34,35].Therefore, physicians should consider the identified patterns ("Disease patterns," "Background patterns," "Clinical factor patterns," and "Clinical management patterns").Further validation in confirmatory factor analysis and other methods when managing multimorbidity should be done.As a next step in clinical education and training, a guide for treating "vascular" in "Disease patterns" in a clinic visit as a place of care, or a guide for treating "ambulatory internal medicine diseases" in an outpatient clinic setting could be considered [8][9][10].
Third, whether the results of this study can be generalized is debatable, especially because the response rate was 25.3%.However, the surveyed physicians, including geriatric and randomly selected primary care specialists, have a certain representativeness of physicians engaged in the medical management of older people in Japan.It is therefore possible to use the present results as basic data regarding the treatment of older patients with multimorbidity and the characteristics of physicians.However, the ratio of geriatricians and primary care specialists to the total number of physicians in Japan is quite low, and there are limitations in predicting overall trends among physicians based on the results of this study.Considering clinical education such as intensive lectures to improve knowledge levels may be warranted, for example, for "geriatric syndromes" or workshop-style training programs for problem-solving in the overall approach to multimorbidity, as well as conducting empirical studies [8][9][10][11].
Fourth, it is possible that the respondents in this study represent a group that had available time to participate in the survey and their opinions may not reflect those of geriatricians and general practitioners who are overworked.Moreover, with a median age of 53 years, the responses may not reflect the opinions of relatively young physicians.
In conclusion, we found that among geriatricians and primary care physicians, the approach to treating older patients with multimorbidity was related to the years of experience and clinical setting as well as the physician's sex.The present results could be used to inform lifelong learning in the form of discussions between physicians with relatively long careers and those with relatively short careers, taking into account whether physicians are practicing in hospital wards or providing home medical care.To enhance the quality of care for older patients with multimorbidity, there is a need for clinical education and training that takes these factors into consideration.

Table 3 . Descriptive statistics of difficult backgrounds. Not at all difficult Not very difficult Quite difficult
https://doi.org/10.1371/journal.pone.0302532.t003 Table includes an overall results for the comparison of mean scores for each factor of each scale and characteristics of respondents.S1 Fig shows a box-plot diagram of factors with statistically significant differences in the group comparison.

Table 4 . Descriptive statistics of clinical factors. Not at all important Not very important
Response patterns were based on a 4-point Likert scale from totally disagree = 1 to totally agree = 4.ADLs, activities of daily living; QOL, quality of life.https://doi.org/10.1371/journal.pone.0302532.t004