A Suspected Association Between Sarcoidosis and Development of Diabetes Mellitus

Study Overview
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Brief Summary
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The purpose of the study is to determine the characteristics of patients with diabetes and sarcoidosis and to compare them with those of patients with diabetes and no sarcoidosis. The investigators will approach these aims by measuring hemoglobin A1c, C peptide, insulin levels, and 2-hour glucose tolerance test results on the study population as well as collecting clinical data from records. Three groups of patients will be identified from pulmonary and endocrinology clinics at the University of Alabama at Birmingham. The first group will have a diagnosis of sarcoidosis without diabetes, the second group will have a diagnosis of both sarcoidosis and diabetes, and the third group will have a diagnosis of diabetes without sarcoidosis. Sample size is not pre-determined, but investigators anticipate this number to be less than 100. These patients will be asked in person during an office visit to join the study. For each patient who agrees to join, at a clinic visit, investigators will review and sign consent. Following the visit or at a time convenient for each patient, study subjects will undergo a fasting plasma venous sample collection for a hemoglobin A1c, C peptide, insulin level and perform a 2-hour oral glucose tolerance test. The degree of glucose intolerance and prevalence of diabetes will be analyzed and compared between the groups and to historical published control data via T test comparisons. At a later separate visit, patients recruited will undergo ultrasound of the pancreas to assess pancreatic size and morphology.

Official Title
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A Suspected Association Between Sarcoidosis and Development of Diabetes Mellitus

Conditions
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Sarcoidosis, Diabetes Mellitus

Intervention / Treatment
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* Diagnostic Test: Venous blood sample
* Diagnostic Test: Ultrasound of pancreas


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Any adult patient referred to or followed in UAB pulmonary clinic with an established diagnosis of sarcoidosis. Any adult patient followed in UAB endocrinology clinic with a diagnosis of diabetes mellitus (excluding type 1 diabetes). Exclusion Criteria: Type 1 diabetes and/or chronic use of corticosteroids.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Sarcoidosis Patients<br>Patients referred to UAB Pulmonology who are diagnosed with sarcoidosis. | Diagnostic Test: Venous blood sample<br>* Venous blood samples will be obtained for hemoglobin A1c, C peptide, insulin level, and 2-hour fasting glucose tolerance test.<br>Diagnostic Test: Ultrasound of pancreas<br>* Ultrasound of pancreas will be obtained on all study participants.<br>|
| Diabetes Patients<br>Patients followed by UAB Endocrinology with diabetes mellitus. | Diagnostic Test: Venous blood sample<br>* Venous blood samples will be obtained for hemoglobin A1c, C peptide, insulin level, and 2-hour fasting glucose tolerance test.<br>Diagnostic Test: Ultrasound of pancreas<br>* Ultrasound of pancreas will be obtained on all study participants.<br>|
| Sarcoidosis and Diabetes patients<br>Patients followed by UAB Pulmonary and/or UAB Endocrinology with both sarcoidosis and diabetes mellitus. | Diagnostic Test: Venous blood sample<br>* Venous blood samples will be obtained for hemoglobin A1c, C peptide, insulin level, and 2-hour fasting glucose tolerance test.<br>Diagnostic Test: Ultrasound of pancreas<br>* Ultrasound of pancreas will be obtained on all study participants.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in glucose during oral glucose tolerance test (oGTT) |  | Baseline | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in C peptide over oGTT |  | Baseline | 
| Change in insulin response oGTT |  | Baseline | 
| Hemoglobin A1c (HbA1c) |  | Baseline |