Occurrence of Undiagnosed Diabetes Mellitus With Musculoskeletal Disorders of the Upper Extremity: Prospective Screening With Point‐of‐Care Haemoglobin A1c Fingerstick Testing

ABSTRACT

Introduction

Upper extremity conditions such as carpal tunnel syndrome (CTS) are more prevalent in patients with diabetes mellitus (DM) than in the general population. This prospective study aimed to determine the viability of DM screening for patients presenting with upper extremity musculoskeletal disorders in an orthopaedic hand clinic and to inform future testing criteria for orthopaedic surgeons.

Methods

Patients with a diagnosis of CTS, trigger finger, Dupuytren's contracture, and/or De Quervain's disease were prospectively enroled. Eighty‐four patients (60.7% female, 60.0% White) underwent point‐of‐care haemoglobin A1c (HbA1c) fingerstick testing at their appointment at the orthopaedic surgeon's office. Patient demographics and disease characteristics (symptom laterality, diagnosis of upper extremity pathologies) were collected and compared between patients with HbA1c within normal limits (HbA1c < 5.7) and in the range of prediabetes or type 2 DM (HbA1c ≥ 5.7).

Results

Among 84 patients, 58.3% had HbA1c in the range of prediabetes and 4.8% in the T2DM range. The most prevalent upper extremity condition was trigger finger (78.6%), and 62.1% of patients presenting with trigger finger had elevated HbA1c. Among patients with prediabetes/T2DM, 43.4% did not have a primary care provider. Patients with elevated HbA1c were significantly more likely to have unilateral symptoms (p = 0.03) and be female (p = 0.008).

Conclusions

Hand surgeons can successfully identify patients with elevated HbA1c, particularly in the range of prediabetes where the disease state is more reversible. Point‐of‐care HbA1c testing could be incorporated into hand surgery practices as a low‐cost and rapid intervention to optimise outcomes of surgery and facilitate earlier treatment of hyperglycemia.

1. Introduction

The prevalence of diabetes mellitus (DM) has progressively grown in the US (CDC ²⁰²⁴), and is estimated to increase to nearly 55 million people in the United States by 2030 (Rowley et al. 2017). Nearly one quarter of the patients in this estimate are undiagnosed (Rowley et al. 2017), and therefore do not receive the necessary counselling and treatment to manage the consequences of elevated blood sugar. Hyperglycemia and its associated glycation end products cause structural and functional impairment to both vessels and nerves, resulting in neuropathies and angiopathies that can affect nearly every organ system in the body (Daryabor et al. 2020; Farmaki et al. ²⁰²⁰; Lotfy et al. ²⁰¹⁷). If left untreated, long‐term complications of type 2 DM (T2DM) include nephropathy, retinopathy, cardiovascular disease, and musculoskeletal disorders, which may contribute to the high rates of emergency department visits, hospitalisations, and deaths attributable to DM and its associated morbidities (CDC ²⁰²⁴).

Upper extremity conditions such as trigger finger, carpal tunnel syndrome (CTS), Charcot's joint, and frozen shoulder are common musculoskeletal pathologic manifestations of T2DM and may have a profound impact on patient pain, function, and quality of life (Choi et al. 2022; Sözen et al. ²⁰¹⁸). Prior studies have estimated the prevalence of trigger finger in as many as 20% of patients with DM, compared to 1%–2% in the general population (Koh et al. 2010; Löfgren et al. ²⁰²¹; Vance et al. ²⁰¹²; Wiwanitkit and Wiwanitkit ²⁰¹²). Similarly, CTS was estimated to be prevalent in 14% of patients with DM versus 3% of the general population (Atroshi et al. 1999; Perkins et al. ²⁰⁰²). The hand surgeon's office is therefore a promising avenue to identify patients with undiagnosed prediabetes or T2DM, especially those presenting with known risk factors such as obesity and hypertension (NIDDK ²⁰²²).

Despite the well‐documented prevalence of upper extremity pathologies in patients with DM, there is a paucity of literature surrounding how this may be used to intervene in the DM disease course. Cheng et al. (2025) previously demonstrated the benefits of point‐of‐care blood glucose screening for patients with diabetes prior to corticosteroid injections, which are known to induce or exacerbate hyperglycemia, in a hand and upper extremity surgery clinic. The integration of point‐of‐care DM screening into the daily workflow of a hand surgery office is yet to be explored. This study aims to determine how the diagnosis of upper extremity conditions—including CTS, trigger finger, Dupuytren's contracture, and De Quervain's disease—can be used to identify undiagnosed diabetes and ultimately inform testing criteria and appropriate counsel for diabetic management by orthopaedic surgeons.

2. Methods

Patients with a diagnosis of CTS, trigger finger, Dupuytren's contracture, and/or De Quervain's disease were enroled between June 2024 and August 2025 in a prospective study conducted at an outpatient hand and wrist surgery practice. Insured patients meeting enrolment criteria were referred to the study or identified via the electronic medical record (EMR) using a consecutive sampling method and were screened for eligibility based on presence of diagnosis for upper extremity pathology. Patients were then independently reviewed by a hand surgeon to confirm diagnosis. Exclusion criteria included an existing diagnosis of type 1 or type 2 DM, active pregnancy, or inability to provide informed consent. Our sample size was calculated based on the total Queens County population of 2.3 million residents. Assuming an expected diabetes prevalence of 9.9% based on estimates of diabetes in Queens County in 2021 and the proportion of type 1 versus type 2 DM diagnoses (NYSDH ²⁰²¹), we determined that 137 patients would be needed to estimate prevalence with a 95% confidence level and a 5% margin of error. A total of 100 patients were enroled in the study, and 16 patients were excluded due to an error message reading insufficient/clotted sample or previously unidentified history of T2DM diagnosis (Figure 1). Post hoc analysis demonstrated that with our observed T2DM prevalence of 4.8% in our cohort, this sample size achieved a margin of error of ± 4.6% at the 95% confidence level. This study was conducted in accordance with the ethical principles of the Declaration of Helsinki. This protocol was approved by the Institutional Review Board (approved 24 January 2022, IRB#21‐1254) and all procedures were performed within the laws and institutional guidelines. Written informed consent was obtained from all patients included in the study.

FIGURE 1.

Flowchart for patient enrolment and inclusion in the final analysis. T2DM, type 2 diabetes mellitus.

Patients underwent a point‐of‐care HbA1c test following the test protocol for the Siemens DCA Vantage analyser machine. The test was performed by the principal investigator or research coordinators, and all research personnel underwent annual training conducted by the institution's Clinical Laboratory Operations department. The Siemens DCA Vantage analyser machine was re‐calibrated for each lot of reagent cartridges used on the system, and weekly quality control testing using control samples was performed. Regular institutional audits were performed to confirm quality control testing and ensure adherence to the institutional protocol. In the point‐of‐care HbA1c test, the index finger was sterilised and a small aliquot of blood was collected in a capillary holder via a finger stick. The capillary holder was immediately inserted into a reagent cartridge, and then run through a standardised test sequence in the DCA Vantage analyser. HbA1c results were recorded, and patients were informed of their results. Patients with elevated HbA1c levels (≥ 5.7) were counselled to follow up with their PCP, and those who did not have a PCP were aided by appropriate primary care referrals. Patient demographics (age, sex, height, weight, body mass index [BMI]) and disease characteristics (symptom laterality, diagnosis of other upper extremity pathologies) were obtained from the EMR. A record of the patient's prior primary care appointments and type of insurance was also collected.

Descriptive statistics were performed to characterise the cohort and compare demographics and disease characteristics between patient HbA1c levels (non‐elevated, prediabetes, and T2DM), and n (%) or mean (standard deviation, SD) were reported. Chi‐squared tests were performed to compare categorical variables between patients with and without prediabetes/T2DM. Binary logistic regression analysis was performed to examine the associations between DM status (coded as a binary variable) and several variable categories. Separate regression analyses were conducted to assess relationships with patient demographics, disease characteristics, insurance status, and records of PCP appointments within 1 year of Hb1Ac testing. All models were adjusted for covariates of age and sex. Significance was p < 0.05. Statistics were performed using IBM SPSS Statistics.

3. Results

One hundred patients were enroled, and 16 patients were excluded due to insufficient/clotted sample or a previously unidentified history of T2DM diagnosis for a total of 84 patients in the final cohort (Figure 1). The majority of patients were female (60.7%), and the most common race was White (60.0%) (Table 1). The most prevalent upper extremity conditions in the cohort were trigger finger (78.6%) and carpal tunnel syndrome (39.3%). A total of 53 patients (63.1%) had elevated HbA1c levels, with 49 patients (58.3%) in the prediabetic range and 4 patients (4.8%) in the T2DM range (Figure 2). The average BMI of patients with prediabetes or T2DM was 29.6 (SD [5.8]) and 28.3 (SD [3.3]), respectively, and nearly half (45.3%) of patients with elevated HbA1c levels had Medicare insurance. Only 32.1% of patients with prediabetes/T2DM had a PCP appointment within 1 year of their HbA1c test, and 43.4% of this subgroup did not have a PCP. PCP appointment history and access were not significantly associated with elevated HbA1c.

TABLE 1.

Characteristics of the cohort.

Variable	Normal HbA1c (n = 31)	Elevated HbA1c
		Prediabetes (n = 49)	T2DM (n = 4)
Age (mean [SD])	64.4 [11.8]	65.9 [11.2]	65.0 [16.4]
Sex
Female	13 (41.9%)	35 (71.4%)	3 (75.0%)
Male	18 (58.1%)	14 (28.6%)	1 (25.0%)
Race
White	19 (61.3%)	25 (51.0%)	3 (75.0%)
Black or African American	4 (12.9%)	7 (14.3%)	0 (0.0%)
Asian	3 (9.7%)	3 (6.1%)	1 (25.0%)
Other	3 (9.7%)	10 (20.4%)	0 (0.0%)
Declined or unknown	2 (6.5%)	4 (8.2%)	0 (0.0%)
BMI (mean [SD]) a	27.6 [4.6] (n = 30)	29.6 [5.8] (n = 41)	28.3 [3.3]
Upper extremity condition(s) b
Carpal tunnel syndrome	21 (67.7%)	30 (61.2%)	3 (75.0%)
Trigger finger	25 (80.6%)	38 (77.6%)	3 (75.0%)
De Quervain's tenosynovitis	0 (0.0%)	3 (6.1%)	0 (0.0%)
Dupuytren's contracture	0 (0.0%)	3 (6.1%)	0 (0.0%)
Multiple upper extremity conditions	11 (35.5%)	14 (28.6%)	1 (25.0%)
Bilateral symptoms	24 (77.4%)	27 (55.1%)	2 (50.0%)
Medicare insurance	12 (38.7%)	23 (46.9%)	2 (50.0%)
Has a PCP	19 (61.3%)	27 (55.1%)	3 (75.0%)
PCP appointment within 12 months of HbA1c test	13 (41.9%)	15 (30.6%)	2 (50.0%)

Abbreviations: BMI, body mass index; PCP, primary care provider; SD, standard deviation; T2DM, type 2 diabetes mellitus.

^a BMI was not collected for all patients.

^b Patients may have more than one upper extremity condition.

FIGURE 2.

HbA1c levels in the cohort. T2DM, type 2 diabetes mellitus.

Of the 66 patients with trigger finger in the cohort, 57.6% had prediabetes and 4.5% had T2DM. Among the 54 patients with CTS in the cohort, 55.6% had prediabetes and 5.6% had T2DM. All patients in the cohort with De Quervain's tenosynovitis and Dupuytren's contracture had prediabetes (Figure 3).

FIGURE 3.

HbA1c levels stratified by upper extremity condition. Percentage calculated from the total number of patients with the upper extremity pathology. T2DM, type 2 diabetes mellitus.

There was a significant difference in the presence of bilateral upper extremity symptoms between patients with and without prediabetes/T2DM (54.7% vs. 77.4%, χ ²(1) = 4.33, p = 0.037, φ = 0.23), representing a small‐to‐medium effect size. Patients with prediabetes/T2DM had 70% lower odds of presenting with bilateral symptoms compared with patients without prediabetes/T2DM (OR = 0.30, CI: [0.10, 0.88], p = 0.028). Female patients in the cohort had significantly higher odds of prediabetes/T2DM than male patients (OR = 0.28 for males, CI: [0.11, 0.71], p = 0.008).

4. Discussion

Our study suggests that hand surgeons may utilise point‐of‐care HbA1c testing to identify patients with elevated HbA1c, particularly in the range of a diagnosis of prediabetes, who may otherwise not receive screening from a primary care physician. We identified elevated HbA1c levels in 63.1% of our cohort, and nearly half of these patients did not have a PCP. The most common hand pathology in this cohort was trigger finger, and 62.1% of patients with trigger finger had HbA1c levels in the prediabetes or T2DM range. Patients with prediabetes/T2DM were significantly more likely to be female and have unilateral symptoms, which may inform targeted screening of patients with these and other risk factors. Our data support the utility and successful incorporation of low‐cost and rapid point‐of‐care HbA1c testing in the hand surgeon's office, which may allow the hand surgeon to provide invaluable preventive care for patients beyond the upper extremity.

More than half of the cohort had HbA1c levels measured in the range of prediabetes, which was substantially higher than the estimated 12.4% of adults with prediabetes in our institution's county in 2021 (NYSDH ²⁰²³). As most adults with prediabetes in New York State do not have a formal diagnosis (NYSDH ²⁰²⁴), it is essential to screen high risk patients even in a specialised clinic such as a hand surgery office, as is evident in the striking rate of elevated HbA1c in this cohort. Prior work by Sohler et al. (2016) examined over 2000 patients eligible for HbA1c screening by American Diabetes Association Screening criteria across urban primary care clinics. Despite differences in methodology and screening, they reported prediabetes prevalence rates (45.2% and 56.7% in two clinic groups) that were comparable to our own study. This alignment suggests that specialty clinics such as the hand surgeon's office may potentially serve as an alternative approach to traditional screening pathways, particularly for reaching patients with prediabetes. Diagnosis with T2DM typically involves an HbA1c blood test, which estimates the patient's average blood glucose levels over the 3 months before the blood draw (NYSDH ²⁰²⁴). This test is commonly ordered by a patient's PCP and may require travel to a separate testing site. This presents obstacles to care for those who do not have a PCP, are uninsured, and/or are unable to travel or allocate time for an additional testing appointment. These factors may contribute to the high prevalence of undiagnosed DM and could be addressed through the incorporation of point‐of‐care HbA1c testing in the hand surgery clinic. A small blood sample would be collected via a finger stick during a patient's appointment, and an in‐office benchtop device would provide results in as little as 6 minutes. Individual tests may cost under $10, although purchase or lease of the devices and requisite supplies can vary (Whitley et al. 2015).

Trigger finger was the most common upper extremity pathology in our cohort, and 62.1% of patients with trigger finger had prediabetes/T2DM. Prior work reported DM in 56.3% of a cohort of 103 patients with trigger finger (Sarkar et al. 2019), which was lower than the prevalence in our cohort but still underscores the large number of patients who may benefit from screening for T2DM. An equally prominent 61.1% of patients with CTS in our cohort had elevated HbA1c, which aligned with previous studies describing greater rates of CTS in patients with DM than in the general population (Atroshi et al. 1999; Perkins et al. ²⁰⁰²). Our data suggest that diagnosis with trigger finger or carpal tunnel syndrome should be carefully assessed by the hand surgeon, particularly when presenting with additional risk factors for DM.

Notably, nearly half of the patients with prediabetes/T2DM in our cohort did not have a PCP, and for patients who did have a PCP, the majority had not had a primary care appointment within 1 year of the HbA1c test performed in our office. The prevalence of patients without a PCP was greater than a 2022 report, citing that 23.3% of adults in Queens do not have a PCP (NYSDH ²⁰²²). For patients without a PCP or insurance, the hand surgeon's office may therefore be one of the only opportunities for diabetic screening due to lack of access or education. Patients present for evaluation at a hand clinic with conditions such as CTS or trigger finger, particularly when these conditions cause pain or disability that impacts their work and activities of daily living (Levine et al. 1993).

We identified several factors significantly associated with elevated HbA1c levels. Females had significantly higher odds of prediabetes or T2DM than males, which is likely in part due to the higher prevalence of carpal tunnel syndrome, trigger finger, and De Quervain's disease in females compared with males (Makkouk et al. 2007; McDiarmid et al. ²⁰⁰⁰; Wolf et al. ²⁰⁰⁹). Although there are also sex‐based differences in DM epidemiology, these are complex and heavily influenced by hormonal factors, especially in women (Kautzky‐Willer et al. ²⁰²³; Mauvais‐Jarvis et al. ²⁰²⁰). Female sex may be a factor for consideration in DM risk assessment and testing criteria. We were surprised to find that patients with prediabetes/T2DM were more likely to have unilateral symptoms rather than bilateral symptoms. This data contradicted other studies that reported greater bilateral versus unilateral presentation of CTS and trigger finger in patients with T2DM, which authors attributed to the systemic nature of this disease (Brown and Genoway 2011; Dong and Liu ²⁰²²; Fitzgibbons and Weiss ²⁰⁰⁸; Zhang et al. ²⁰²¹). This finding might be attributed to variations in the demographics and disease profile in our cohort, or potentially the enrolment of patients earlier in the disease process. Limitations in the size and sex distribution of our cohort should be considered with these analyses, and future studies across a wider geographic distribution are needed.

We hypothesise that our data reflects screening of patients early in the DM disease process; of the 53 patients in our cohort with elevated HbA1c levels, 92.4% had prediabetes and were therefore in an earlier and more reversible disease state (NYSDH ²⁰²⁴). This finding may be additionally supported by the low proportion of patients in the cohort with multiple upper extremity pathologies. Our data emphasises the pivotal role that the hand surgeon can play in screening and early diagnosis of prediabetes and T2DM, which is particularly important when considering that diabetes may complicate treatment for common hand pathologies. Patients with T2DM are shown to be less responsive to or contraindicated for initial less‐invasive treatments such as corticosteroid injection (Baumgarten et al. 2007; Fitzgibbons and Weiss ²⁰⁰⁸), which can cause a transient steroid‐induced hyperglycemia (Stepan et al. 2014). Cheng et al. (2025) performed point‐of‐care blood glucose testing on diabetic patients prior to corticosteroid injection in a hand and upper extremity surgery clinic and demonstrated its benefits in identifying hyperglycemia prior to injection. They further found that diabetic patients with hyperglycemia who followed up with their medical provider demonstrated reductions in their HbA1c values, suggesting that DM screening in the hand surgeon's office has the potential to instigate improvements in the disease course. Diagnosis of diabetes mellitus must also be considered in decision‐making surrounding surgical options and perioperative care, as T2DM is a known risk factor for post‐operative complications such as delayed wound healing and infection (Knoedler et al. 2024).

Our study is not without limitations. Our findings should be interpreted in the context of potential selection bias. Enroled patients primarily resided in the same or adjacent county to the study institution (Queens County, New York), which limits the generalisability of the data to other regions. The cohort demographics closely reflect the census‐reported demographics for our county and may differ from those of other communities. Further, Queens County demonstrates pronounced economic stratification that may not have been represented in the sampled group. All patients seen at the hand and wrist clinics of this study had insurance. Approximately 8.2% of the population of Queens County does not have insurance (NYSDH ²⁰²⁶), meaning these patients were not enroled in this study. Patients presenting to a hand surgery clinic may represent a specific demographic with different healthcare access patterns, and future studies should explore these socioeconomic and geographic factors. Next, the subgroup of patients with HbA1c levels in the range of T2DM was very small, possibly due to the identification of patients early in the disease process. However, patients were not assigned a clinical diagnosis in this study and were therefore analysed as one group with elevated HbA1c levels, which did not allow us to draw conclusions between the subgroups. Future studies with a larger T2DM subgroup that more closely reflects the prevalence in the enrolment county are necessary to address this limitation and strengthen the comparison. This study also had several strengths. We enroled a robust cohort of patients for which we had detailed patient‐ and disease‐level data, and utilised a modern point‐of‐care HbA1c testing device that was National Glycohemoglobin Standardisation Programme (NGSP)‐certified and regularly calibrated using standard controls. The use of a benchtop device reduced patient burden by eliminating the need to travel off‐site for a formal blood draw. This ultimately streamlined the screening process as HbA1c levels were measured in the same office as the patient's original appointment, and the results were available in approximately 6 minutes.

5. Conclusions

This study demonstrates that point‐of‐care HbA1c testing may be integrated in the hand surgery office to screen for prediabetes and T2DM, thereby allowing providers to counsel patients to seek appropriate follow‐up testing and care when they may otherwise go undiagnosed and untreated. Patient presentation, including the presence of unilateral symptoms and other known risk factors for DM, may inform the selection of patients to screen for prediabetes and T2DM. Future studies are necessary to determine if patients identified with elevated HbA1c in the hand office had subsequent follow up with a primary care physician and indicated intervention for DM. Larger scale studies with a control group and larger T2DM subgroup may increase the generalisability of our results and further explore the potential incorporation of HbA1c screening in the hand office.

Author Contributions

Chloe Heiting: data curation, formal analysis, investigation, methodology, writing – original draft, visualization, writing – review and editing. Catherine Baylor Wickes: project administration, supervision, writing – review and editing. Sruthi Katakam: data curation, formal analysis, investigation, methodology, writing – review and editing. Carolina Herrera: data curation, formal analysis, investigation, methodology, writing – review and editing. Brian Li: project administration, supervision, writing – review and editing. Jessica Intravia: conceptualization, project administration, supervision, writing – review and editing. John E. Nolan: project administration, supervision, writing – review and editing. Kate W. Nellans: conceptualization, project administration, supervision, writing – review and editing.

Funding

The authors have nothing to report.

Ethics Statement

This protocol was approved by the Northwell Health Institutional Review Board (approved 1/24/2022, IRB#21‐1254) and all procedures were performed within laws and institutional guidelines.

Consent

Written informed consent was obtained from all patients included in the study.

Conflicts of Interest

The authors declare no conflicts of interest.

Data Availability Statement

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.