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. 2025 Nov 14;20(11):e0336915. doi: 10.1371/journal.pone.0336915

An osteoporosis course as a separate component of problem-based learning

Iva Hoffmanová 1,*,#, Valér Džupa 2,#, Petr Waldauf 3,#, Robert Grill 4,‡, Václav Báča 5,‡
Editor: Muhammad Abbas Abid6
PMCID: PMC12617839  PMID: 41237112

Abstract

The objective was to compare the extent of acquired knowledge regarding osteoporosis-related issues in a group of medical students who successfully completed an optional “Elective Osteoporosis Course” based on problem-based learning, and a group of medical students who completed only the mandatory curriculum.

Study groups and methods

Study group I was comprised of 25 fourth-year students who successfully completed the Elective Osteoporosis Course I (focused on pathophysiology, diagnostics, and pharmacological treatment), while control group I was comprised of 25 fifth-year students who successfully completed only all required fourth- and fifth-year courses, but did not participate in the elective Osteoporosis I course. Study group II was comprised of 27 fourth-year students who successfully completed the Elective Osteoporosis Course II (focused on treatment of osteoporotic fractures), while control group II was comprised of 24 sixth-year students who were preparing for final exams in surgical disciplines, but did not participate in the Elective Osteoporosis Course II. The groups were compared using a linear regression model with robust estimation of standard errors using Stata 13.1. A p-value < 0.05 was considered statistically significant.

Results

Study Group I scored, on average, 6.7 points higher than Control Group I on the multiple-choice test (scale –16 to +21). Study Group II scored, on average, 3.5 points higher than Control Group II on the multiple-choice test (scale –21 to +28). Both differences were statistically significant (p < 0.001, R2 = 0.64, 95% CI: 5.2–8.1; p = 0.006, R2 = 0.15, 95% CI: 1.1–5.9; respectively).

Conclusion

Results demonstrated a greater understanding in students who participated in problem-based learning medical studies relative to those who completed only the mandatory curriculum.

Introduction

Osteoporosis represents a growing global healthcare challenge, affecting approximately 21.2% of women and 6.3% of men over the age of 50 worldwide. Osteoporotic fractures, especially hip fractures, are associated with serious complications and a mortality rate of 20–24% within the first year post-fracture. With the global population aging, the incidence of hip fractures is projected to double by 2050, thereby intensifying the burden on healthcare systems worldwide [1].

Despite its clinical significance, osteoporosis remains underrepresented in medical education and clinical practice. Moreover, as a multidisciplinary condition, its teaching is often spread across several study subjects, which can result in students developing a fragmented understanding of the disease. This gap contributes to delayed diagnosis, suboptimal management, and disconnection between theoretical knowledge and its application. Given the increasing prevalence of osteoporosis and osteoporotic fractures worldwide, a more comprehensive integration of this condition into medical curricula is warranted.

At our Faculty of Medicine, we introduced an optional course called the Elective Osteoporosis Course, which is based on the principles of problem-based learning (PBL). This structure enables students to choose topics of interest while ensuring coverage of essential material.

PBL in pre-clinical medical studies is considered an effective method for integrating theoretical and clinical knowledge [2–4]. Elective courses on interdisciplinary topics, such as osteoporosis, can, through PBL, integrate and consolidate educational content that is otherwise dispersed across multiple mandatory courses [5–12].

At our faculty, osteoporosis-related topics are spread across five mandatory courses within the compulsory curriculum: (1) Diagnostics based on imaging techniques; (2) Hematology and Oncology; (3) Diabetology, Endocrinology, Gastroenterology, and Abdominal Surgery; (4) Nephrology, Urology, Rheumatology, and Geriatrics; and (5) Orthopedics, Traumatology, Anesthesiology and Resuscitation. The Elective Osteoporosis Courses were designed to consolidate existing content from the aforementioned mandatory courses without introducing new material, focusing specifically on the pathophysiology, diagnosis, and management of osteoporosis and osteoporotic fractures. The course was required to be offered as an elective, as the current curriculum did not permit it to be designated as mandatory.

This study aims to assess, based on multiple-choice test scores, whether participation in the PBL-based Elective Osteoporosis Course enhances students’ knowledge of osteoporosis-related issues compared with students who complete only the compulsory curriculum, which is largely grounded in traditional didactic teaching methods.

Methods

Course structure

The Elective Osteoporosis Course consisted of two sequential sub-courses:

  • Elective Osteoporosis Course I focused on definition, clinical presentation, biomechanics, bone metabolism, diagnostic approaches, and pharmacological treatment of osteoporosis.

  • Elective Osteoporosis Course II addressed disease progression and treatment of typical osteoporotic fractures.

Each sub-course included 14 study hours, combining 10 hours of self-directed e-learning via an online platform (http://osteokurz.lf3.cuni.cz/) and two interactive 2-hour seminars. The e-learning component provided a structured knowledge framework, effectively preparing students for the seminars. The interactive seminars, conducted in PBL format, focused on the discussion and analysis of illustrative clinical cases.

All students participated in the interactive seminars and were divided into five groups beforehand. After completing the e-learning module, each group received a specific clinical case topic, which enabled focused preparation. In each seminar, five cases were discussed, resulting in a total of ten clinical cases per sub-course.

Each case began with the presentation of anamnesis and physical examination findings, followed by the assigned group’s proposed diagnostic approach. Their reasoning was subsequently discussed with the other groups and the faculty, who guided the debate and provided feedback aligned with established clinical practice.

In the Elective Osteoporosis Course I, the subsequent steps included the evaluation of diagnostic methods, with attention to differential diagnosis, and the development of management strategies encompassing pharmacological treatment, potential side effects of the treatment, and lifestyle modification. This course, therefore, emphasized the principles of diagnosis and long-term disease management.

In the Elective Osteoporosis Course II, the subsequent steps focused on the evaluation of diagnostic methods for osteoporotic fractures, and the development of management strategies centered on fracture treatment and rehabilitation. This course was thus oriented toward the practical aspects of acute fracture care and subsequent rehabilitation.

At each stage, students articulated the rationale for their decisions, engaged in peer-to-peer discussion, and received faculty evaluation

Building on the solid theoretical foundation established in the preceding e-learning module, the seminar structure allowed students to consolidate their knowledge through practical application, to engage actively in clinical reasoning and collaborative problem-solving, and to benefit from peer-to-pear learning while integrating multiple aspects of patient management. Collectively, these activities contributed to a more comprehensive understanding of osteoporotic care.

Assessment

Each sub-course was completed by taking a final test comprising 10 multiple-choice questions randomly selected from a pool of 100 items. Unlike a conventional multiple-choice test with simple right/wrong scoring, this assessment used a scaled scoring system. Each answer option was assigned a numerical value rating from strongly positive (highly correct) to strongly negative (incorrect). Highly correct answers yielded strongly positive scores, less accurate but still plausible answers provided smaller positive values, while incorrect choices were penalized with negative scores, ranging from mildly negative for partially incorrect options to strongly negative for clearly erroneous ones. This approach discouraged random guessing and allowed the test to capture how well students distinguished between more and less plausible alternatives. Each question in each set of ten multiple-choice questions was designed to be equivalent in content and to maintain a numerically balanced distribution of response options.

A minimum score of 70% was required to pass the test and, where applicable, to receive course credit. The test was integrated into the e-learning platform.

  • For the Elective Osteoporosis Course I test, achievable scores ranged from –16 to +21 points, with the 70% passing threshold set at 10 points. This corresponded to approximately 5 points more than could be obtained by indiscriminately marking all options for all questions.

  • For the Elective Osteoporosis Course II test, scores ranged from –21 to +28 points, with the 70% passing threshold set at 14 points. This corresponded to approximately 7 points more than could be obtained by indiscriminately marking all options for all questions. The elevated passing threshold was intentionally established at a slightly greater margin than in Course I to accommodate the broader distribution of potential scores.

In both courses, the passing threshold was determined to ensure that students’ performance reflected genuine understanding rather than random chance or exhaustive completion. This type of test is developed, implemented, and validated by experts in medical testing at the Third Faculty of Medicine, Charles University, Prague, Czech Republic.

Both the Study Groups and the Control Groups completed the test under standardized conditions, in a lecture hall using computers via an online platform, under the supervision of the teacher. The test was administered with a time limit of 30 minutes.

Participants and groups

  • Study Group I: 25 fourth-year students who voluntarily chose and completed the Elective Osteoporosis Course I.

  • Control Group I: 25 fifth-year students who completed the mandatory osteoporosis-related coursework in their fourth and fifth year, but did not take the elective course. This group was selected to ensure that the content and scope of the presented and assessed material related to osteoporosis in the mandatory curriculum corresponded to that presented in the Elective Osteoporosis Course I.

  • Study Group II: 27 fourth-year students who voluntarily chose and completed the Elective Osteoporosis Course II. Of these, 25 students had previously completed Elective Osteoporosis Course I, while 2 students were newly included.

  • Control Group II: 24 sixth-year students who completed all mandatory courses covering osteoporosis, including fifth-year courses in Orthopedics and Traumatology of the musculoskeletal system, but did not participate in the elective course. At the time of testing, these students were preparing for final examinations in surgical disciplines. This group was selected to ensure that the content and scope of presented and assessed osteoporosis material in the mandatory curriculum corresponded to that covered in the Elective Osteoporosis Course II.

All groups shared exposure to the standard curriculum (based on traditional didactic teaching methods); however, elective participants (Study Groups I and II) received consolidated and focused instruction using PBL.

The elective course’s voluntary nature introduces potential self-selection bias, as students opting may have greater baseline interest or motivation. The elective format was chosen because mandatory integration into the existing curriculum was not feasible, and this is recognized as a limitation.

Ethics statement

The study adhered to institutional guidelines for educational research, and all participants provided verbal informed consent prior to testing. The consent was witnessed by the teacher who supervised the test-taking process, and documented by the fact that all participants answered all test questions

Statistical analysis

Group comparisons were performed using a linear regression model with robust standard errors (Stata 13.1). A p-value < 0.05 was considered statistically significant. Results are presented as regression coefficients (difference between group means) with 95% confidence intervals and coefficient of determination (R2). Moreover, the Bayes’ theorem was utilized to enrich the statistical point of view.

Results

Elective osteoporosis course I test results

In Study Group I (n = 25), 24 students (96%) successfully passed the course test and were awarded credit; one student failed to achieve the required minimum score and therefore did not receive credit. In contrast, only one student (4%) in Control Group I (n = 25) passed the test, while the remaining 24 were unsuccessful. Table 1 summarizes the distribution of points earned. As illustrated in S1 Graph, Study Group I scored on average 6.7 points higher than Control Group I, a difference was significant (p < 0.001, R2 = 0.64, 95% CI: 5.2–8.1).

Table 1. Elective Osteoporosis Course I test: Comparison of points acquired by Study Group I and Control Group I.

Number of points acquired Number of students

Study Group I (NI)		 Number of students

Control Group I (nI)
2 2
3 1 1
4 3
5 6
6 5
7 6
8 1
9
10
11 11
12 2
13 5 1
14 1
15 1
16 1
17 3
Total number of students 25 25
Open in a new tab

The test data presented above illustrate the impact of PBL using basic statistical analysis. The testing methodology assumes random data selection, with no cross-references between input variables and process conditions.

The effectiveness of PBL can be further evaluated through more advanced statistical methods – for example, by applying Bayes’ theorem of conditional probability, where the condition is participation in the course. The positive results of the test under the condition of attending the PBL course represent a conditional probability. This probability, denoted as P(test_positive ǀ attending_PBL), can be calculated as the ratio of the joint probability of attending the PBL course and achieving a positive result, P(attending_PBL ∩ test_positive), to the overall probability of a positive test result, P(test_positive).

P(test_positive ǀ attending_PBL) = P(attending_PBL ∩ test_positive)/ P(test_positive)

Using this approach, the resulting probability of success on the test is 96%. This means that students who completed the Elective Osteoporosis Course I would pass the test with a 96% probability.

Elective Osteoporosis Course II Test Results.

All students in Study Group II (n = 27) successfully passed the test and were awarded credit. In the Control Group II (n = 24), 17 students (71%) passed, while the remaining 7 were unsuccessful. The point distribution is presented in Table 2. Study Group II achieved an average score 3.5 points higher than Control Group II, with this difference also reaching statistical significance (p = 0.006, R2 = 0.15, 95% CI: 1.1–5.9), as shown in S2 Graph

Table 2. Elective Osteoporosis Course II test: Comparison of points acquired by Study Group II and Control Group II.

Number of points acquired Number of students

Study Group II (NII)		 Number of students

Control Group II (nII)
11 2
12 2
13 2
14 1
15 1 2
16 2 1
17 2
18 1 2
19 2
20 1
21 5
22 7 2
23 2 3
24 4
25 1
26 1 2
27 1
28 2
Total number of students 27 24
Open in a new tab

Applying Bayes’ approach, the resulting probability of success on the test is 99%. This means that students who completed the Elective Osteoporosis Course II would pass the test with a 99% probability.

Discussion

This study evaluated the impact of an Elective Osteoporosis Course combining self-directed e-learning with PBL seminars for fourth-year medical students. Osteoporosis, a critical and growing health concern, merits enhanced focus within undergraduate medical education, and our course was designed to address this need by consolidating knowledge distributed across several mandatory subjects.

We adopted a blended approach, integrating e-learning with case-based seminars that employ PBL methods, for several reasons: (1) contemporary medical students at our faculty prefer e-learning materials, (2) Problem and Case-Based Learning aligns well with modern educational theories emphasizing contextual and applied knowledge [13–22], (3) the authors of this article have had positive experiences with e-learning studies used by junior doctors preparing for specialized exams (Educational Center for Anatomy and Endoscopy: http://ecae.lf3.cuni.cz/ and the Center for Integrated Study of the Pelvis: http://medical-cisp.lf3.cuni.cz/). It turned out that osteoporosis was a suitable choice for creating an elective course, as more than 250 students have completed the course over its 12 years of existence.

The considerable difference in the test scores between Study Group I and Control Group I can be ascribed to the fact that the Elective Osteoporosis Course I was more theoretically oriented. Fifth-year medical students, who did not participate in the elective course (Control Group I) demonstrated less detailed knowledge of osteoporosis pathophysiology, diagnostics, and pharmacological treatment than students who engaged with the elective’s structured, PBL-oriented content, indicating that participation in the elective contributed to improved knowledge retention.

Conversely, the smaller but still significant difference observed in the Elective Osteoporosis Course II (Study Group II vs. Control Group II) may be attributed to the clinical emphasis on this study phase. The sixth-year students who did not participate in the elective course (Control Group II) had already completed courses in Orthopedics and Traumatology of the musculoskeletal system, including case presentations of osteoporotic fractures, partially bridging the knowledge gap.

We acknowledge the potential influence of self-selection bias, as students opting into the elective course may have been more motivated or had prior interest in osteoporosis, which could have contributed to the observed differences. Additionally, the extra study time inherent to the elective course may have also contributed to the improved outcomes. This limitation should be taken into account when interpreting our findings.

Our results align with previous research supporting the efficacy of PBL in medical education [17–22]. Notably, our study highlights the value of elective, focused courses that complement core curricula by integrating knowledge across disciplines through active, case-based learning. Consistent with other authors [13–16], we emphasize the critical role of case study analysis in reinforcing clinical reasoning and knowledge retention. The superior performance of Control Group II relative to Control Group I likely reflects their increased exposure to clinical case-based learning in later years.

Although comparison with a traditional course was not possible in this study, we suggest that future research could involve a controlled comparison between PBL and traditional teaching approaches to better understand the relative efficacy of each method. Further studies might consider randomized controlled designs comparing PBL with traditional didactic teaching to better delineate relative benefits.

Conclusion

This study demonstrates a higher degree of knowledge in medical students who, in addition to finishing the standard osteoporosis curriculum, completed an elective course—combining e-learning with problem-based interactive seminars. The e-learning component established essential theoretical groundwork, while the PBL format fostered active learning, critical thinking, and deeper understanding.

Our findings support PBL as an effective method for integrating comprehensive, up-to-date disease knowledge across diverse medical disciplines, which is particularly important for multifaceted conditions like osteoporosis. Elective courses can be a suitable complement to the traditional curriculum, especially for multidisciplinary medical topics.

Finally, these results reinforce the widely recognized advantage of incorporating case studies into both preclinical and clinical education to enhance long-term retention and application of theoretical knowledge.

Supporting information

S1 Graph. Elective Osteoporosis Course I test: Comparison of points acquired by control group I and study group I.

(DOCX)

pone.0336915.s001.docx (37.9KB, docx)
S2 Graph. Elective Osteoporosis Course II test: Comparison of points acquired by control group II and study group II.

(DOCX)

pone.0336915.s002.docx (39.5KB, docx)
S1 Data. Data for Graph 1 and 2.

(DOCX)

pone.0336915.s003.docx (33KB, docx)
S1 Raw Data. Raw data Study I vs Control I.

(XLSX)

pone.0336915.s004.xlsx (10.2KB, xlsx)
S2 Raw Data. Raw data Study II vs Control I.

(XLSX)

pone.0336915.s005.xlsx (10.3KB, xlsx)

Data Availability

All relevant data are within the paper and its Supporting Information files.

Funding Statement

The author(s) received no specific funding for this work.

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Decision Letter 0

Muhammad Abbas Abid

23 Jul 2025

Dear Dr. Hoffmanová,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

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Additional Editor Comments:

The topic of the study is important as Osteoporosis is a multi-specialty condition often neglected. However, the manuscript and the methodology requires much greater rigor and explanation.

First, the authors state that osteoporosis is an emerging health problem but fail to mention how that is an emerging problem. A little detail about its prevalence and distribution will add more interest and relevance to the Introduction.

Similarly, the 2 groups need to be defined in much greater detail as there is overlap and discreet differences in the 2 groups. As the course was elective, and rightly so, it adds selection bias. Please mention why the course was elective (probably because it was not possible to make it mandatory), and mention it clearly in the limitations.

Please take a closer look at the reviewers' comments and address them all (specially the details shared by Reviewers 2, 4 and 5). Addressing this will not only add clarity to the study, but will also make it an interesting read.

I understand that there is quite some work required to turn it into a really interesting read but I believe it is worth a shot as the topic is both interesting and relevant.

Good luck to the authors and I applaud their efforts!

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

Reviewer #1: Yes

Reviewer #2: Partly

Reviewer #3: No

Reviewer #4: No

Reviewer #5: Partly

**********

2. Has the statistical analysis been performed appropriately and rigorously? -->?>

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: I Don't Know

Reviewer #4: No

Reviewer #5: No

**********

3. Have the authors made all data underlying the findings in their manuscript fully available??>

The PLOS Data policy

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: Yes

Reviewer #5: Yes

**********

4. Is the manuscript presented in an intelligible fashion and written in standard English??>

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: Yes

Reviewer #5: Yes

**********

Reviewer #1: Thank you for asking to review this manuscript.

It is a well conducted study related to Med Education and authors have indeed done a good job.

Aim is clearly mentioned and study is designed as per aim too.

They conduced the a very good analysis of both cohorts and described the results in a precise and legible way.

They have also discussed their outcomes very nicely with pertinent references.

Reviewer #2: The effect of Problem Based Learning (PBL) on medical students' learning outcomes is a very interesting area of research and the authors course design and outcomes are of interest and worthy of publication. However, the paper needs significant revision before it should be considered for publication.

More specific comments are included in the attached PDF, which has highlights and comments on the original paper. Particular care should be given to addressing the issues highlighted in red.

Here I will give general comments and advice for resubmission:

The authors have chosen to present this as a quantitative paper however they have not addressed several issues which arise due to the non-randomized selection of students into the study and control groups. This needs to be addressed.

Education is not a perfect science and even for a quantitative analysis of the outcomes more detail regarding the students motivation (for selection the course) and the background environment (what does it mean to "pass or fail" the course. etc.) need to be given in order for readers to be able to generalize the outcomes to their own educational situations.

Possibly, it would have been better to compare two elective courses, one taught with a PBL style and one with a more traditional approach.

It is suggested that the authors either address the issues above or reorient the paper to focus on a descriptive/qualitative view of the course before resubmitting the paper for publication.

Reviewer #3: My major concern with this study is that it is not a comparison of two instructional methods but rather it appears that both groups experienced the same [mandatory] curriculum while the study groups who used the elective had ADDITIONAL study of osteoporosis. Perhaps I misinterpreted how the authors presented the different study/control groups but it would seem logical that students with more and varied exposure to a problem would perform better on a knowledge test regarding that problem. I find it difficult to attribute better performance to the use of PBL under these circumstances. If the study groups did not participate in the mandatory osteoporosis curriculum then the comparison would be more legitimate.

Another difficulty I had in understanding the data presented was the fact that "test points" ranged from -x to +y. It is not clear to me how a test score could be negative [-].

Reviewer #4: The manuscript addresses an important topic in medical education by exploring the effects of an elective osteoporosis course using a problem-based learning (PBL) approach. The study is relevant given the interdisciplinary nature of osteoporosis and the increasing interest in active learning methods. While the research question is meaningful, several aspects of the study design and reporting require clarification or improvement, as detailed below.

1. The authors emphasize the use of PBL in the Elective Osteoporosis Course, which is a valuable teaching method. PBL focuses on student-centered learning, encouraging collaborative problem-solving in groups, which helps students develop critical thinking and problem-solving skills. However, the manuscript provides limited detail on the specific execution of PBL, including group configurations, lesson planning, and implementation processes. Providing more information on these aspects would help readers better understand how PBL was applied in this course.

2. If the authors intended to compare the elective and mandatory courses, they should more explicitly contrast their educational approaches, course content, and outcomes. For example, the authors could compare how the integration of osteoporosis into mandatory courses contrasts with the more focused approach of the elective course. Additionally, they could clarify if and how the elective course offers advantages in terms of student engagement, knowledge retention, and clinical application compared to the mandatory courses. This comparison would provide a clearer understanding of the relative effectiveness of the elective course in enhancing students’ knowledge of osteoporosis.

3. The manuscript does not clearly state whether Study Group I and Study Group II also completed the related mandatory courses on osteoporosis. This is essential information, as it affects the interpretation of the study results. If the study groups completed both mandatory and elective courses, the findings support the additive value of the elective course. If they only took the elective course, the results would suggest it may serve as an effective substitute or standalone intervention. Clarifying this point would strengthen the study’s conclusions.

4. In this study, all students in the study groups were in their fourth year, while the control groups consisted of fifth- and sixth-year students. This difference in academic level introduces significant confounding variables, such as variation in clinical exposure, exam preparation status, and recency of learning. These factors could affect knowledge retention and test performance independently of the elective course. The current comparison design limits the ability to attribute differences in outcomes solely to the elective course. I recommend that the authors acknowledge and discuss this limitation in the manuscript.

5. Since the elective course was likely voluntary, the study may be subject to self-selection bias. Students who chose to enroll in the elective may be more motivated or academically stronger, which could independently influence their test performance. I recommend the authors acknowledge and discuss this potential source of bias.

6. It appears that the test questions used to assess both the study and control groups were randomly selected from a larger pool of 100 items, meaning that each student received a different set of questions. While this approach increases variety and minimizes recall bias, it raises concerns about the comparability of scores across groups, as the difficulty level of each test version may vary. I recommend that the authors clarify whether any standardization or item difficulty balancing was applied.

7. The study would benefit from a more detailed description of the research procedure. Key aspects such as the timing of the assessments, the conditions under which the tests were administered, and whether the procedures were standardized across groups are not clearly stated. Additionally, information on participant selection or group assignment is lacking. Clarifying these points would help assess the internal validity of the study and the reliability of the comparisons made.

8. The manuscript states that the study does not involve human subjects and therefore did not require ethics approval. However, it involves collecting and comparing the test results of identifiable student groups under different instructional conditions, which typically falls within the scope of educational research involving human participants. I recommend that the authors clarify whether institutional ethics review was conducted or waived, and whether informed consent was obtained from participants.

9. The statistical analysis uses linear regression with robust standard errors, which is appropriate. However, the manuscript lacks details regarding covariate control or model assumptions. Were any variables such as academic year or prior GPA considered as potential covariates? Clarifying this would strengthen the interpretation of the results.

Reviewer #5: The authors conducted a study to investigate the effect of an Elective Osteoporosis Course on 4th year medical students' Osteoporosis related knowledge acquisition. It is a good attempt to renovate PBL with this self-directed learning driven elective course. However, several issues need to be addressed to improve the manuscript:

1. Major Concern: Study design is a major concern. Based on the description,

1) Study group 1 students seem to complete the Elective Osteoporosis Course on top of finishing all mandatory courses, while control group students only complete the mandatory courses. If so, it would not be a surprise that study group 1 students could have higher scores.

2) Study group 2 students differ from study group 1 students, which disrupts the ability to exam the continuity of course and its longitudinal effect on knowledge acquisition, given course 1 and course 2 are two parts of the Elective Osteoporosis Course.

3) The sample size is not large, leading to the results may be easily distorted by confounders (e.g. student aptitude). The authors should specify how they control confounders and provide effect size under Results.

2. Other Issues:

1) Study goal: The authors are suggested to specify the study hypothesis and the outcome measures of "depth of acquired knowledge".

2) Methods:

A) Please add a "Participants and Setting" section to help readers understand the context of this study.

B) The authors are recommended to illustrate the data collection and analysis process with a flowchart.

C) Please provide validity evidence of the knowledge measurement exam/tool. It is necessary to support the results are reliable and valid.

3) Results and Discussion:

A) The authors are suggested to discuss potential implication, such as whether the traditional mandatory courses would be replaced by this elective course.

B) Please add study limitations.

**********

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Reviewer #1: Yes:  Dr Maseeh uz Zaman

Reviewer #2: Yes:  Francesco Bolstad

Reviewer #3: No

Reviewer #4: No

Reviewer #5: No

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Attachment

Submitted filename: comments.pdf

pone.0336915.s006.pdf (1.8MB, pdf)
PLoS One. 2025 Nov 14;20(11):e0336915. doi: 10.1371/journal.pone.0336915.r003

Author response to Decision Letter 1

5 Oct 2025

Dear Dr. Muhammad Abbas Abid and Reviewers,

Thank you very much for your thoughtful and constructive feedback on our manuscript titled „An Osteoporosis course as a Separate Component of Problem-Based Learning“

We appreciate the time and effort invested in reviewing our work and value the insightful comments that helps us improve the quality and clarity of the manuscript. Below we provide detailed responses to each point raised, along with descriptions of the changes made in the revised manuscript. In the revised version of the manuscript, the changes are highlighted in yellow.

________________________________________

General response to Additional Editor Comments

In the Introduction, we have added a more comprehensive introduction outlining the epidemiology and significance of osteoporosis as an emerging health problem, including recent prevalence data and the burden of disease.

In the Methods, subsection Participants and groups, we have clarified the definition and characteristics of the Study and Control groups.

In the Introduction, we have explained, why the course was elective.

Potential for self-selection bias are mentioned in the Methods, specifically in the end of Participants and group subsection, and in the Disscusion.

All reviewer comments have been addressed in detail below.________________________________________

Responses to Reviewers

________________________________________

Reviewer #2

Comments in the attached PDF:

We have addressed all comments, as detailed below:

Elective Course & Biases: We clarified the meaning of the Elective Course in the ‚Introduction‘. Potential biases are mentioned in the ‚Methods‘ section, specifically in the end of ‚Participants and group‘ subsection, and in the ‚Disscusion‘ section.

• Abstract:

1. Used optional “Elective Osteoporosis Course” to emphasize the elective nature of the course.

2. Corrected highlighted words.

3. Added the test scale in the parenthesis.

• Introduction: Provided a more detailed rationale for osteoporosis as a health issue and for the creation of the “Elective Osteoporosis Course”.

• Methods:

1. Explained the sequence of self-study e-learning followed by in-class sessions.

2. Addressed possible selection bias under Study Groups; omitted the word successfully for Study Group I.

3. Clarified that all Control Group I students completed all 4th-year and 5th-year osteoporosis-related courses.

4. Detailed the multiple-choice test methodology and passing criteria.

• Results:

1. Moved the test description and scoring from the ‚Results‘ to the ‚Methods‘ section; clarified credit conditions.

2. Explained clearly which students passed/failed and received/did not receive credit.

3. Added missing words.

• Conclusion: removed “unequivocally proved” and clarified, why Problem-Based Learning likely contributed to better knowledge retention.

General comments - major points:

1. Non-randomized selection and potential bias:

We acknowledge that the elective nature of the course introduces a self-selection bias as students with a particular interest or motivation in osteoporosis may be more likely to enroll. This is now explicitly stated in the ‚Methods‘ section, specifically in the end of ‚Participants and group‘ subsection, Unfortunately, randomization was not feasible given the educational context. We have revised the manuscript to emphasize this limitation and discuss its implications for generalizability in the ‚Disscusion‘ section.

2. Details on student motivation and background environment:

For greater clarity, we have newly divided the 'Methods' section into the following subsections: 'Course Structure', 'Assessment', and 'Participants and Groups'. We added following information in the 'Methods' section: The academic context is described in 'Course Structure' subsection. The criteria for passing or failing the course are described in 'Assessment' subsection. The factors influencing student motivation to take the elective course are mentioned in 'Participants and Groups' subsection.

3. Suggestion to compare two elective courses:

While comparing two elective courses with different teaching methods would be ideal, in this study only the osteoporosis elective was available as an additional course. In the ‚Discussion‘ section, we have noted this as a limitation and suggested it as an area for future research.

________________________________________

Reviewer #3

Major concerns:

1. Clarification on groups and additional exposure:

For greater clarity, we have newly divided the 'Methods' section into the following subsections: 'Course Structure', 'Assessment', and 'Participants and Groups'. We clarified in the 'Participants and groups' subsection, that all students completed the mandatory curriculum on osteoporosis, and the study groups additionally completed the elective course. This was added to the manuscript to highlight that the elective course was supplementary, which may explain the better test performance in study groups. We mentioned that as a limitation of the study in the 'Methods' section, specifically in the end of 'Participants and groups' subsection, and in the 'Discusion'.

2. Clarification on test scores and negative values:

In the 'Assessment' subsection, we described in detail how the multiple-choice final test was designed, including an explanation of why the achieved scores could range from negative to positive values

Reviewer #4

Detailed methodological clarifications requested:

1. Details on PBL implementation:

For greater clarity, we have newly divided the 'Methods' section into the following subsections: 'Course Structure', 'Assessment', and 'Participants and Groups'. In the 'Course Structure' we better described course design, with detailed information about the PBL implementation, facilitated by using case study learning. In the 'Participants and Groups' section are better described group sizes, and characteristics.

2. Comparison of elective vs mandatory courses:

In the section 'Participants and Groups' we now better clarified these differences and how the elective course complements the mandatory curriculum. Reasons for the better knowledge retention in PBL course are described in the subsection 'Course Structure', and also mentioned in the ‚Discusion‘.

3. Clarification of group composition: The manuscript now explicitly states that, all Study Group completed the mandatory courses in their study years. Additive value of the elective course is mentioned as a limitation study in the 'Methods' section, specifically in the end of 'Participants and groups' subsection, and in the 'Discusion'.

4. Academic level differences: are now better described in the 'Participants and groups' subsection, where the comparison of academic level is mentioned too. In the 'Discusion' is it also mentioned.

5. Self-selection bias acknowledgment:

We acknowledge that the elective nature of the course introduces a self-selection bias as students with a particular interest or motivation in osteoporosis may be more likely to enroll. This is now thoroughly discussed in the „Methods“ section, specifically in the end of „Participants and group“ subsection. We have revised the manuscript to emphasize this limitation in the „Disscusion“ section.

6. Test version comparability:

We clarified design of the final multiple-choice test in the 'Assessment' subsection, including the information, that each set of ten multiple-choice questions was designed to be equivalent in content and to maintain a numerically balanced distribution of response option.

7. Research procedure description:

We added detailed description of timing, test administration, and standardization of conditions in the ‚Assessment“ subsection.

8. Ethics and consent:

We obtained ethics committee approval for this educational research and ensured that all participants provided informed verbal consent. This is now clearly stated in the „Ethics Statement“ section.

9. Statistical analysis details:

In addition to the regression models, Bayes’ theorem was utilized to provide a more comprehensive statistical perspective

________________________________________

Reviewer #5

1. Major concerns:

For greater clarity, we have newly divided the 'Methods' section into the following subsections: 'Course Structure', 'Assessment', and 'Participants and Groups'. In the 'Participants and Groups' subsection, we clarified that the study groups completed both mandatory and elective courses, while controls completed only mandatory. We explained that all students in Osteoporosis Course II had previously completed Course I, while 2 students were newly included. We mentioned the limitations connected with this topic in the 'Discussion'.

2. Other Issues:

1. Study goal:

The hypothesis and primary outcomes (knowledge gain measured by test scores) are now explicitly stated in the 'Introduction' and 'Methods'.

2. Methods:

A) We added the 'Participants and Groups' subsection.

B) Instead of a flowchart, we provided a more detailed characterization of the study groups in the 'Participants and Groups' subsection..

C) Validity evidence of test tool:

In the 'Assessment' subsection we described the nature of the test and who developed and validated it.

3. Results and Discusion

A) Implication of the study are now better mentioned in the 'Conslusion'.

B) In the section 'Discussion', we decribed limitation of our study.

________________________________________

We hope that these revisions adequately address all concerns and improve the manuscript’s clarity, rigor, and overall quality. We thank the editor and reviewers again for their valuable feedback and look forward to your further consideration.

Sincerely,

On behalf of all authors

Iva Hoffmanová, MD, PhD

Second Faculty of Medicine, Charles University

Prague, Czech Republic

Attachment

Submitted filename: The Response to Reviewers.docx

pone.0336915.s007.docx (25.7KB, docx)

Decision Letter 1

Muhammad Abbas Abid

2 Nov 2025

An Osteoporosis Course as a Separate Component of Problem-Based Learning

PONE-D-25-15083R1

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Reviewers' comments:

Acceptance letter

Muhammad Abbas Abid

PONE-D-25-15083R1

PLOS ONE

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Associated Data

    This section collects any data citations, data availability statements, or supplementary materials included in this article.

    Supplementary Materials

    S1 Graph. Elective Osteoporosis Course I test: Comparison of points acquired by control group I and study group I.

    (DOCX)

    pone.0336915.s001.docx (37.9KB, docx)
    S2 Graph. Elective Osteoporosis Course II test: Comparison of points acquired by control group II and study group II.

    (DOCX)

    pone.0336915.s002.docx (39.5KB, docx)
    S1 Data. Data for Graph 1 and 2.

    (DOCX)

    pone.0336915.s003.docx (33KB, docx)
    S1 Raw Data. Raw data Study I vs Control I.

    (XLSX)

    pone.0336915.s004.xlsx (10.2KB, xlsx)
    S2 Raw Data. Raw data Study II vs Control I.

    (XLSX)

    pone.0336915.s005.xlsx (10.3KB, xlsx)
    Attachment

    Submitted filename: comments.pdf

    pone.0336915.s006.pdf (1.8MB, pdf)
    Attachment

    Submitted filename: The Response to Reviewers.docx

    pone.0336915.s007.docx (25.7KB, docx)

    Data Availability Statement

    All relevant data are within the paper and its Supporting Information files.

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