Presentations

Abstract

Introduction: Adhesive capsulitis (AC) of the shoulder, often termed "frozen shoulder," is a common clinical condition characterized by restricted active and passive range of motion at the shoulder joint, frequently associated with pain. AC affects 3-5% of the general population and up to 20% of those diagnosed with diabetes mellitus (DM). There is also evidence of association between AC and hyperlipidemia (HLD), specifically low-density lipoprotein (LDL). While many studies have shown a strong relationship between the prevalence of AC and DM, the use of AC diagnosis as an indication for metabolic disorder testing has been poorly studied. One prior study did find a 38.6% prevalence of DM in patients with AC, and 32.95% prevalence of pre-diabetes in patients with AC, however this study utilized a relatively small sample size and did not test for other metabolic disorders such as HLD. We hypothesized that a large portion of patients with newly diagnosed AC have an undiagnosed metabolic disorder such as diabetes or hyperlipidemia.

Methods: Patients of two orthopedic surgeons at a private practice were identified from clinic schedules between 2022 and 2023 and screened for study eligibility. Patients were included if they were at least 18 years old and had a new clinical diagnosis of AC. Patients were excluded if they had any prior diagnoses of AC, DM or HLD, prior shoulder surgery, chronic pain disorders, or lab work performed within the past 6 months. Following informed consent, participants obtained fasting blood glucose (FBG), HbA1C, and lipid panel lab work. Participant demographics, AC characteristics, and labs were then collected via chart review for analysis. Enrolled patients were informed of their lab results by a research team member and recommended follow-up with their primary care physician in cases of elevated values. All values were graded based on CDC guidelines. Descriptive statistics were performed on patient demographics and lab results using Microsoft Excel.

Results: Of 20 patients who signed informed consent, a subsequent 15 eligible patients obtained labs. Patient ages ranged from 38 to 71 years old, with a mean of 57. There were 12 females (80%) and 3 males (20%). By BMI, 6 (40%) participants classified as overweight and 3 (20%) classified as obese. AC presented equally in each shoulder (7 right, 8 left). By HbA1C, 11 (73%) were normal, 3 (20%) had pre-DM, 1 (7%) had DM. By FBG, 4 (27%) had pre-DM and 1 (7%) had DM. Nine (60%) had elevated cholesterol, 10 (67%) had elevated LDL, 2 (13%) had elevated triglycerides, and all had a high-density lipoprotein (HDL) value greater than 40.

Conclusion: This study found that the majority of participants are not diabetic or pre-diabetic but do have elevated cholesterol (>200 mg/dL) and LDL (>100 mg/dL), which is consistent with prior studies on AC and HLD. The 60% prevalence of elevated cholesterol in this study is much greater than CDC population data, which reports a prevalence of 15.1% in those aged 40-59. As participants did not have any previously diagnosed metabolic disorders, the results of this study suggest that a new diagnosis of AC may indicate underlying HLD. However, our data is limited by small sample size, which may reflect the relative participant burden of fasting, traveling to a lab site, undergoing needle for phlebotomy, and having blood drawn. Future research can further define the strength of the relationship between AC and HLD, as well as consider whether a new diagnosis of AC warrants routine testing for metabolic disorders in all patients.