Diabetes screening and diagnosis Jennifer R Marks, MD

Diabetes screening and diagnosis WHO? WHEN?

Per USPSTF guidelines

For all people, testing should begin at age 45 years. B Recommendations Testing for prediabetes and type 2 diabetes in asymptomatic people should be considered in adults of any age who are overweight or obese (BMI ≥25 kg/m2 or ≥23 kg/m2 in Asian Americans) and who have one or more additional risk factors for diabetes. B For all people, testing should begin at age 45 years. B If tests are normal, repeat testing carried out at a minimum of 3-year intervals is reasonable. C Per American Diabetes Association Guidelines

Per American Diabetes Association Guidelines

Per American Diabetes Association Guidelines

Diabetes screening and diagnosis HOW?

Per American Diabetes Association Guidelines

“There is incomplete concordance between A1C, FPG, and 2-h PG, and the 2-h PG value diagnoses more people with prediabetes and diabetes than the FPG or A1C cut points. Marked discrepancies between measured A1C and plasma glucose levels should prompt consideration that the A1C assay may not be reliable for that individual, since a relatively small percentage of patients have conditions such as sickle cell trait or hemoglobinopathies that skew A1C results.” Per American Diabetes Association Guidelines

Diabetes screening and diagnosis Pitfalls?

Diabetes screening and diagnosis Falsely lowers A1c Falsely raises a1c Any process that shortens the lifespan of the RBC Any process that lengthens the lifespan of the RBC https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3912281/

Pregnancy (less so 3rd trimester) Falsely lowers A1c Falsely raises a1c Anemia from blood loss Hemolytic anemia Splenomegaly Pregnancy (less so 3rd trimester) Vitamin E ingestion (reduced glycation) Ribavirin & interferon- alpha (possible hemolytic anemia) Iron, B12, & folate- deficiency anemia (reduced turnover) Asplenia Uremia Chronic ETOH Chronic salicylate use Chronic opioid use Lead poisoning https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3912281/

Per American Diabetes Association Guidelines

Diabetes screening and diagnosis Take-Home points Screen anyone with risk factors anytime Screen all at age 45 Use combination of HgbA1c, FPG, RPG, OGTT Beware pitfall in using HgbA1c

Diabetes screening and diagnosis ABIM-style question 66 yo M with NIDDM, CAD, htn, and BPH returns to clinic for routine 6-month follow-up. He has taken MTF 1,000mg BID & glipizide 2.5 mg BID for many years with good control (A1c ~ 6.8 historically). He carefully watches his diet, walks his dog 45 minutes daily, and fastidiously charts his BGs which he brings to you in graphic format. All results are <150, and most are about 110 with no hypoglycemia or hypoglycemic symptoms.

You review with him the labs he had drawn several days ago prior to the office visit: HgbA1c 7.3 Sodium 138 Potassium 4.3 Chloride 105 CO2 24 Glucose 88 Calcium 9.8 BUN 12 Creatinine 0.76 LFTs nl WBC 7.6 RBC 3 Hgb 13 Hct 36 MCV 102 RDW 14 Platelets 299 TSH 2.43

The patient is quite upset by the change in his HgbA1c The patient is quite upset by the change in his HgbA1c. You advise the following: A) Continue current regimen including meds, diet & exercise B) Have additional labs drawn C) Consider a vitamin supplement to make him feel better D) All of the above E) None of the above

The patient is quite upset by the change in his HgbA1c The patient is quite upset by the change in his HgbA1c. You advise the following: A) Continue current regimen including meds, diet & exercise B) Have additional labs drawn C) Consider a vitamin supplement to make him feel better D) All of the above E) None of the above

The patient is quite upset by the change in his HgbA1c The patient is quite upset by the change in his HgbA1c. You advise the following: A) Continue current regimen including meds, diet & exercise (avoid overtreatment/hypoglycemia…see below) B) Have additional labs drawn (test for deficiencies underlying his anemia) C) Consider a vitamin supplement to make him feel better (Cyanocobalamin, IF actually deficient) This patient has a macrocytic anemia which may indicate Vitamin B12 deficiency, which is relatively common and can be associated with metformin use. Also this patient is very reliable yet cannot explain this unexpected change in glycemic control.