Examining the Association Between Frequency of Mobile Clinic Visits and Diabetes and Hypertension Control

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The paper is well written and organized. However, there are some minor comments that need to be addressed.

Methods

Page 5, lines 183-185: it was stated that “For patients who were new to the clinic and had less than 1 year of study data, we calculated a projected number of visits per year, adjusting for the duration of observation in the study.” Further explanation is needed regarding how the projected number was calculated and how the adjusting for the duration was done.

Page 5, lines 199-200: If diabetes and hypertension were the main conditions and their values (A1c and SBP/DBP) were the main outcomes; it is not clear why they were used as covariates.

 

Discussion

potential reasons why mobile clinic didn’t significantly improve A1c could be added.

I understand that the data was not collected for research purpose and that some variables were missing. Was adherence to treatment/recommendations assessed? it could explain the results.

 

Conclusion

Page 15, lines 454-456: the results showed that number of comorbidities was not significantly associated with level of A1c. This statement should be interpreted with caution.

Author Response

Thank you for your thoughtful feedback. I have provided a point-by-point response in the attached document, with notes indicating the location of any revisions made in the manuscript.

Please let me know if any additional clarification would be helpful.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Peer-reviewed report for the manuscript titled “Examining the Association Between the Frequency of Mobile Clinic Visits and Chronic Illness Control.”

This manuscript investigates the relationship between the number of mobile clinic visits and the control status of individuals with diabetes or hypertension, while adjusting for demographic factors, socioeconomic characteristics, and comorbidities. The findings indicate that, while the frequency of mobile clinic visits is associated with improved hypertension control, it does not appear to have the same effect on diabetes control.

Overall, the manuscript is a pleasure to read. The topic is highly relevant to public health. However, I have several suggestions to enhance the quality of the manuscript.

1. “Chronic illness” is a broad term with a specific meaning in public health and clinical medicine. The most commonly recognized chronic illnesses include cardiovascular diseases (such as hypertension, coronary artery disease, heart failure, and stroke), diabetes (specifically type 1 and type 2; gestational diabetes is not chronic but is related), chronic respiratory diseases (including COPD, asthma, chronic bronchitis, and emphysema), cancer (all major types), chronic kidney disease (stages 1–5, including end-stage renal disease), and chronic liver disease. Additionally, there are other specific functional illnesses, such as Alzheimer's disease, Parkinson's disease, and multiple sclerosis. The authors only examine two conditions within the broader category of chronic illnesses. I suggest renaming the manuscript to reflect this focus better.
2. The authors need to provide more detail regarding the statement on lines 137-138: “Patient medical record charts were reviewed to determine study inclusion or exclusion.” Specifically, it should be clarified whether the reviewer (1) determines the criteria for inclusion and exclusion or (2) selects the subjects for the study. If the answer is (1), please explain how the criteria and the selection process are related. If the answer is (2), please define the specific selection criteria.
3. The statement on lines 140-142, “From a clinical perspective, individuals in this age range are more likely to have chronic illnesses of interest per our study criteria,” does not adequately explain the inclusion criterion for adults aged 26 years and older. Research indicates that conditions such as diabetes and hypertension typically emerge around the age of 40. I suggest that the authors offer a more explicit rationale for this inclusion criterion. One possibility is that individuals at age 26 may lose their parents’ medical insurance and thus seek alternative healthcare options, which the Well of Healing Mobile Medical Clinic provides.
4. The study sample must be more transparent: Of 218 regular patients, 86 (39%) had diabetes, 129 (59%) had hypertension, and 3 (2%) had neither (?).
5. For patients diagnosed with either diabetes or hypertension (HTN), was there a comorbidity of HTN or diabetes? According to Table 2, 76.7% (66 individuals) with diabetes also have hypertension, while 13.2% (17 individuals) with hypertension have co-existing diabetes. The authors need to clarify how they determined which condition would be considered the primary condition.
6. Lines 146-147 discuss the “new patients.” How recent are these patients? Did they visit the clinic for the first time in early 2018 or late 2019? Were they diagnosed with diabetes or hypertension (or both) before or after their first clinic visit?
7. In the “Diabetes and Blood Pressure Data Analysis Flow Diagram” figure and elsewhere in the Methods Section, the authors must provide a clear definition of the term “Dichotomous interval.”
8. The authors need to explain why they excluded individuals with fewer than 2 A1C tests and blood pressure measurements recorded within the 2 years of the study period. Were any of these individuals “new” patients?
9. Lines 170-181 – Since each patient should have at least two A1C results (for diabetes) or two blood pressure measurements (for hypertension), it is crucial to clarify how these dependent variables are defined. Should they be averaged, taken as the mean, or represented by the lowest or highest values? The author must provide a clear explanation of how these two dependent variables are defined.
10. In lines 173-174, diabetes control is defined as having a hemoglobin A1c level below 6.5%, according to the Centers for Disease Control and Prevention (CDC) guidelines [16]. However, the reference to the CDC website is no longer available. It is important to note that the American Diabetes Association recommends classifying diabetes as “controlled” when the A1c is less than 7%, while an A1c level above 6.5% is used as the threshold for diagnosing diabetes.
11. Lines 178-181 state, “According to the Eighth Joint National Committee (JNC-8) hypertension guidelines, for individuals aged 18 to 59 years without major comorbidities, and for patients aged 60 years or older who have diabetes, chronic kidney disease, or both conditions, the target blood pressure level is less than 140/90 mm Hg.” I am unsure how this statement fits into the paragraph.
12. Given that the dependent variable, A1C level, is continuous, conclusions should not focus on controlled diabetes, defined by the authors as an A1C level of less than 6.5%. In comparison, the standard classification is less than 7%. Instead, the interpretation should be that more or less frequent visits do not correlate with changes in A1C levels, which can increase or decrease.
13. The sample sizes were modest. A significant number of participants from the diabetes cohort were excluded from the analysis, potentially reducing statistical power. This issue should be added to the authors' limitations.

Author Response

Thank you for your thoughtful feedback. I have provided a point-by-point response in the attached document, with notes indicating the location of any revisions made in the manuscript.

Please let me know if any additional clarification would be helpful.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Overall, this is a well-written manuscript dealing with an interesting topic.

The title is informative and concise enough.

The Introduction provides enough information for readers to understand the basic theory of the link between access to care and chronic diseases, as well as the current situation related to the diabetes and hypertension in the specific region the study refers to.

In lines 85-86 the authors refer to a specific report but fail to include the reference. Please, revise.

Lines 120-125: There should be a geographical determinant of this research included in the aim, regardless of California being mentioned in the previous sentence.

Materials and Methods section is well organized. However, this section lacks some explanation which I tried to point out below.

Line 139: What was the rationale behind the age 26 as a cut-off point?

Lines 145-146: Were there any patients that had both, DM2 and hypertension? These chronic diseases have shared risk factors. Could there be confounding? How was this question addressed? Was it addressed?

Lines 161-163: The authors state that “Presence of diabetes was identified in the patient chart by record of disease diagnosis and/or prescription of diabetes medication (e.g., metformin, glipizide).” In cases identified by, for example, metformin use – was the possibility of metformin being prescribed for insulin resistance in prediabetes of PCOS accounted for? The fact that a person has been prescribed metformin does not determine the diagnosis of DM. Could the authors please explain this further?

The same applies to the identification of hypertensive patients – there are some antihypertensives that can be used to treat conditions other than hypertension (e. g. some beta-blockers can be used in treatment of anxiety, tremor, migraine prevention). Please provide more details on the identification of patients in relation to these issues.

Results section is in line with the aim, and the Discussion section is clear with results appropriately interpreted. No issues identified here.

The conclusions are concise enough and consistent with the results.

The references are relevant.

Author Response

Thank you for your thoughtful feedback. I have provided a point-by-point response in the attached document, with notes indicating the location of any revisions made in the manuscript.

Please let me know if any additional clarification would be helpful.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

I want to thank the authors for addressing my previous comments and revising the manuscript accordingly. Aside from two minor concerns, they have adequately addressed my feedback.

Comment #5: The authors might consider adding a mention of the limitation concerning the lack of consideration for comorbidity during the data analysis.

Comment #10: The sentence stating, “Control of diabetes was defined as hemoglobin A1c < 6.5% based on the Centers for Disease Control and Prevention (CDC) guidelines,” is still inaccurate according to the recently updated reference, the CDC website. The current guidelines indicate that an A1c level greater than 6.5% is the diagnostic threshold, and the recommended goal for glycemic control is an A1c of less than 7%. I suggest the authors revise the sentence to clarify that an A1c level of <6.5% was used as a clinical benchmark for glycemic control within the mobile clinic, even though the CDC guidelines recommend that “For most people with diabetes, the A1C goal is 7% or less.”

Congratulations on the work well done.

Author Response

Thank you for the opportunity to make revisions to the manuscript. I have provided responses noted in the document attached. 

Author Response File: Author Response.pdf