ADA 2025 Standards – Section 6 Notes: Glycemic Goals & Hypoglycemia

Assessment of Glycemic Status

  • Three complementary measurement modalities
    • HbA1c (laboratory or point-of-care)
    • Blood Glucose Monitoring (BGM) via capillary finger-stick devices
    • Continuous Glucose Monitoring (CGM) with metrics such as Time-in-Range (TIR), mean glucose, time-above-range (TAR), time-below-range (TBR)
  • Recommendation hierarchy
    • 6.1 Assess with HbA1c A-level evidence and/or CGM metrics B-level
    • Alternative when HbA1c unreliable: fructosamine, glycated albumin, or CGM B-level
    • 6.2 Frequency: ≥2 times yr; every ≈3 months if off-target, treatment changes, high variability, growth spurts, etc. E-level

Glycemic Assessment by HbA1c

  • Reflects ~2–3 mo mean plasma glucose; NGSP-standardized assays show excellent analytic performance
  • Testing schedule
    • Newly diagnosed → baseline value
    • Stable, at goal → twice yr
    • Unstable/therapy changes/intensive plans → quarterly or more
    • Point-of-care HbA1c enables same-visit treatment adjustment
  • Interference & caveats
    • Conditions altering RBC turnover: hemolysis, anemias, G-6-PD deficiency, transfusion, erythropoiesis-stimulating drugs, ESRD, pregnancy → spurious values
    • Hemoglobin variants: most heterozygous variants fine; homozygous (HbSS, HbEE) → HbA absent → cannot measure
    • Does not capture acute variability or hypoglycemia; discordance possible
    • Race/ethnicity differences in HbA1c–glucose relationship exist, but are not clinically actionable; avoid race-based adjustments

Serum Glycated Protein Assays (Fructosamine & Glycated Albumin)

  • Reflect prior 2–4 wk glycemia; highly correlated with each other
  • Linked to long-term complications in cohort studies, but few RCTs; evidence base weaker than HbA1c
  • Useful when HbA1c uninterpretable/unmeasurable (e.g., homozygous Hb variants)

HbA1c ↔ Mean Glucose Equivalence (ADAG study)

  • Strong correlation r=0.92r = 0.92; ADA/AACC endorse reporting eAG with HbA1c
  • Rough conversions (95 % CI shown in original Table 6.1)
    • 5 % ≈ 97 mg/dL97\,\text{mg/dL}
    • 6 % ≈ 126 mg/dL126\,\text{mg/dL}
    • 7 % ≈ 154 mg/dL154\,\text{mg/dL}
    • … up to 12 % ≈ 298 mg/dL298\,\text{mg/dL}
  • Limitations: single 2008 study, early CGM tech, calibration issues; generalizability to modern sensors uncertain

Blood Glucose Monitoring (BGM)

  • Integral for insulin-treated people; informs meal/activity responses and dose titration
  • Frequency & timing individualized (see Section 7)

Continuous Glucose Monitoring (CGM)

  • Particularly valuable for insulin users and hypoglycemia-prone individuals (type 1, insulin-treated type 2, CF-related DM, etc.)
  • Data sufficiency: ≥10–14 days with ≥70 % wear for reliable assessment
  • Key actionable metrics (International Consensus)
    • TIR 70–180 mg/dL (3.9–10.0 mmol/L)
      • Goal: >70 % adults; >50 % older adults
      • 70 % TIR ≈ HbA1c ≤7 %
    • TBR <70 mg/dL (<3.9 mmol/L)
      • Goal: <4 % (<1 % older adults)
    • TBR <54 mg/dL (<3.0 mmol/L)
      • Goal: <1 %
    • TAR 181–250 mg/dL (10.1–13.9 mmol/L)
      • Goal: <25 % adults; <50 % older adults
    • TAR >250 mg/dL (>13.9 mmol/L)
      • Goal: <5 % adults; <10 % older adults
    • Coefficient of variation ≤36%\le 36\% (≤33 % gives extra hypo protection)
  • Ambulatory Glucose Profile (AGP) provides standardized visualization (median, 25ᵗʰ–75ᵗʰ, 5ᵗʰ–95ᵗʰ percentiles)
  • Remote data sharing expanding (telehealth, downloads)

Glycemic Goals (Non-Pregnant Adults)

  • Core recommendations
    • 6.3a HbA1c <7 % (<53 mmol/mol) for many adults without severe/frequent hypo A-level
    • 6.3b TIR >70 % for CGM users B-level
    • 6.3c TBR <4 % (<70 mg/dL) and <1 % (<54 mg/dL) B-level
    • 6.4 Lower targets if safe and acceptable B-level
    • 6.5 Less stringent targets in limited life expectancy/high harm B-level
    • 6.6–6.7 De-intensify or switch from insulin/sulfonylurea/meglitinide when hypo-risk high or burden exceeds benefit B-level
    • 6.8 Reassess goals per Fig 6.2 individualized algorithm E-level
    • 6.9 Set/record goals during consultations to improve outcomes A-level
  • Standard adult targets (Table 6.3)
    • Fasting/pre-meal: 80–130 mg/dL80–130\,\text{mg/dL} (4.4–7.2 mmol/L)
    • Peak post-meal (1–2 h): <180 mg/dL180\,\text{mg/dL} (<10 mmol/L)

Individualization Framework (Fig 6.2)

  • Factors: overall health, functional/cognitive status, comorbidities, hypo risk, life expectancy, resources, patient preference
  • Healthy/robust → tighter A1C (<7 %)
  • Complex/intermediate (multiple comorbidities, mild cognitive or ADL deficits) → A1C 7–8 %
  • Very complex/poor health (LTC, ESRD, severe cognitive/ADL limits) → A1C 8–8.5 %
  • Goals evolve over disease course; “metabolic memory” supports early intensive control, later de-intensification as needed

Evidence Linking Glycemia & Complications

  • Microvascular
    • DCCT (type 1): HbA1c ≈7 % vs 9 % → 50–76 % ↓ in retinopathy, nephropathy, neuropathy; benefits persist decades (EDIC)
    • UKPDS & Kumamoto (early type 2): intensive (≈7 %) vs standard → fewer microvascular events; legacy benefits
    • Curvilinear relationship: largest absolute benefit when lowering very high A1C to ~7 %; further drop to 6 % gives smaller incremental gains
  • Macrovascular
    • ACCORD, ADVANCE, VADT: no immediate CV event reduction; ACCORD intensive arm ↑ mortality → caution in long-standing T2DM with aggressive insulin
    • Long-term follow-up (DCCT/EDIC, UKPDS, VADT) shows later CV benefit (“legacy effect”)
    • Modern agents (GLP-1 RA, SGLT2 i) provide CV/renal benefits independent of HbA1c; may be initiated regardless of baseline A1C

Medication Strategy Integration

  1. If already on ≥2 agents but not GLP-1 RA/SGLT2 i, consider switching to one with proven CV benefit
  2. In T2DM + CVD/CKD/HF, may add SGLT2 i or GLP-1 RA even when A1C at goal and/or without metformin

Hypoglycemia: Definitions & Thresholds (Table 6.4)

  • Level 1: <70 \text{ mg/dL} (3.9 mmol/L) & ≥54 mg/dL (3.0 mmol/L)
  • Level 2: <54 \text{ mg/dL} (3.0 mmol/L) — neuroglycopenia threshold
  • Level 3: Severe, requiring external assistance (altered consciousness), regardless of glucose reading
Recommendations 6.10–6.19 (Key Points)
  • Review hypo history each visit; document frequency/severity
  • Annual screening for impaired awareness, fear of hypo, cognitive decline
  • Classify patients:
    • “At risk” = on insulin, sulfonylurea, or meglitinide
    • “High risk” = ≥1 major risk factor or multiple others (Table 6.5)
  • CGM strongly recommended for high-risk patients (reduces events)
  • Treat conscious episodes with ≈15 g fast carb (or 5–10 g if on AID system); recheck in 15 min; avoid high-fat/protein foods initially
  • Prescribe glucagon to all insulin users or high-risk patients; favor ready-to-use (nasal, pre-filled pen); train caregivers
  • Any Level 2/3 event → reassess & potentially de-intensify therapy
Major & Other Hypoglycemia Risk Factors (Table 6.5 Examples)
  • Major clinical: recent severe hypo, intensive insulin therapy, impaired awareness, ESRD, dementia
  • Major social: food insecurity, low income, housing instability, fasting for religious reasons, under-insurance
  • Other clinical: multiple level 1 events, basal insulin, age ≥75, female sex, high GV, CVD, CKD stage ≥3, neuropathy, depression, polypharmacy
Hypoglycemia Prevention Toolkit (Table 6.7)
  • At initial, follow-up, annual visits: assess history, awareness, cognition; provide structured education; review CGM needs; adjust meds; renew glucagon; consider awareness-restoration programs
  • Structured education programs (BGAT-2, HARPdoc) & avoidance of hypo for few weeks can restore awareness

Glucagon Formulations & Cost (Table 6.6)

  • Powder for reconstitution (1 mg)
  • Nasal powder (3 mg)
  • Ready-to-inject pens/syringes (0.5 mg, 1 mg)
  • Dasiglucagon pen (0.6 mg)
  • Median U.S. 30-day AWP ≈$206−379\approx\$206−379; NADAC ≈$235−298\approx\$235−298

Intercurrent Illness (“Sick-Day” Management)

  • Stressors ↑ risk of both hyper- and hypo-glycemia; may precipitate DKA/HHS
  • Assess need for more frequent glucose & ketone checks; provide dose-adjustment algorithms
  • Drug interactions: fluoroquinolones, clarithromycin, TMP-SMX, metronidazole, fluconazole potentiate sulfonylureas → consider holding/reducing

Hyperglycemic Crises (DKA & HHS)

Diagnostic Criteria (Table 6.8)
  • DKA requires hyperglycemia ≥200 mg/dL200\,\text{mg/dL} or known DM, β-OH-butyrate ≥3 mmol/L or urine ketone ≥++ and acidosis (pH <7.3 or HCO₃ <18)
  • Euglycemic DKA (<200 mg/dL200\,\text{mg/dL}) occurs (~10 % cases) – common with SGLT2 i, pregnancy, fasting, EtOH
  • HHS: glucose ≥600 mg/dL600\,\text{mg/dL}, effective osmolality >300 mOsm/kg300\,\text{mOsm/kg}, minimal ketosis, pH ≥7.3, HCO₃ ≥15
Clinical Presentation (Table 6.10)
  • Polyuria, polydipsia, weight loss; N/V, abdominal pain (DKA); altered mental status (HHS > DKA); Kussmaul respirations (DKA)
Epidemiology & Outcomes
  • Rising rates last decade: type 1 ≈ 45–83 /1000 PY; type 2 ≈ 3 /1000 PY
  • In-hospital mortality: DKA 0.2 % (T1) – 1 % (T2); HHS ~0.8 % (declining)
  • Recurrence common; 1-yr mortality after DKA 13× general population
Risk Factors (Table 6.9)
  • Absolute insulin deficiency, youth, prior crises, high HbA1c, comorbidities, behavioral health disorders, substance use, socioeconomic barriers, infection, MI, trauma, steroids, antipsychotics, checkpoint inhibitors, SGLT2 i (especially in T1DM)
Prevention & Education (Rec 6.20-6.21)
  • Review crisis history each visit; deliver structured “sick-day” education (ketone testing, hydration, never stop basal insulin, when to seek care)
  • Provide 24/7 contact pathways; address social determinants (access to insulin, CGM, supplies)
  • Post-event: screen for barriers, offer DSMES, psychological/peer support; CGM access lowers recurrence risk