Table 1.
Summary of studies reporting the impact of differing GADA titers and/or numbers of positive islet autoantibodies on the prevalence and associated characteristics of LADA
| Study | n | Inclusion criteria | Antibody status and threshold | % of study population | PPV for insulin treatment | Age at diagnosis (years) | BMI (kg/m2) | C-peptide (nmol/L) | TG (mmol /L) |
|---|---|---|---|---|---|---|---|---|---|
| Turner 1997 (13) | 1,538* | Age 25–65 years, diagnosis of T2D | GADA and ICA neg | 88 | 14% at 6 years | — | — | — | — |
| GADA 20–60 units/L | 4.0 | 23% at 6 years | — | — | — | — | |||
| GADA ≥60 units/L | 7.1 | 63% at 6 years | — | — | — | — | |||
| GADA and ICA low titer | 4.3 | 77% at 6 years | — | — | — | — | |||
| GADA and ICA high titer | 3.0 | 89% at 6 years | — | — | — | -— | |||
| Tuomi 1999 (35) | 1,122 | Clinical diagnosis of T2D | GADA <5 RU | 90.8 | — | — | 27** | 0.62 | 2.0** |
| GADA 5–38 RU | 6.2 | — | — | 27** | 0.55 | 1.6** | |||
| GADA >38 RU | 3.0 | — | — | 25** | 0.27 | 1.5** | |||
| Davis 2000 (36) | 1,225 | Diagnosis of T2D at age >60; or no initial insulin | GADA neg | 96.3 | 11.2% at avg. 3 years | 61.1 | 29.6 | — | 1.9 |
| GADA 20–60 units/L | 1.4 | 17.6% at avg. 2.3 years | 58.4 | 27.4 | — | 2.0 | |||
| GADA >60 units/L | 2.3 | 46.4% at avg. 5.3 years | 59.7 | 27.0 | — | 1.3 | |||
| Genovese 2006 (37) | 881 | Diagnosis of T2D at age 40–70 years, hospital based | GADA neg (<3 units) | 95.4 | 20.2% at avg. 8.1 years | 52.0 | 29.2 | — | — |
| GADA 3–10 units | — | 42% at avg. 8.7 years*** | — | — | — | — | |||
| GADA >10 units | — | 73.9% at 8.7 years*** | — | — | — | — | |||
| GADA >3 units and IA-2A | 2.2 | 78.9% at 8.7 years*** | — | — | — | — | |||
| Buzzetti 2007 (34) | 4,248 | 35–75 years at diagnosis, not insulin treated, duration 6 months to 6 years | GADA neg | 95.5 | — | 55.5 | 29.9 | — | — |
| GADA pos <32 units | 2.3 | — | 51.1 | 28.4 | — | — | |||
| GADA pos >32 units | 2.2 | — | 49.1 | 26.2 | — | — | |||
| Maioli 2010 (38) | 5,568 | T2D age 35–70 years, no insulin 8 months post diagnosis; duration <5 years | GADA neg | 95.1 | — | 57.7 | 30.8 | — | 1.4 |
| GADA pos index <0.5 | 2.4 | — | 55.4 | 28.8 | — | 1.3 | |||
| GADA pos index >0.5 | 2.5 | — | 53.4 | 26.9 | — | 1.3 | |||
| Hawa 2013 (18) | 6,156 | Age 30–70 years, no insulin rx for 6 months from diagnosis | GADA neg | 90.2 | 13.2% at avg. 2.3 years | 54.9 | 30.9 | — | 2.0 |
| GADA 70–200 WHO units | 2.2 | 39.7% at avg. 2.5 years | 47.9 | 28.5 | — | 1.8 | |||
| GADA >200 WHO units | 6.5 | 54.6% at avg. 2.1 years | 47.0 | 26.7 | — | 1.2 | |||
| Zhou 2013 (33) | 4,880 | Onset age >30 years, no DKA, no insulin by 6 months, recruit by 1 year of dx | GADA neg | 94.1 | — | 51.4 | 24.8 | 0.64 | 1.8 |
| GADA 18–180 WHO units | 4.3 | — | 51.2 | 24.5 | 0.51 | 1.6 | |||
| GADA >180 WHO units | 1.6 | — | 48.1 | 22.3 | 0.32 | 1.2 | |||
| Maddaloni 2015 (32) | 17,072 | Onset age 30–70 years, no DKA, no insulin rx by 6 months of dx | GADA and IA-2A neg | 97.3 | — | 46.9 | 31.4 | — | — |
| GADA >10 units/mL | 2.6 | 21.8% at 5 years | 45.1 | 30.7 | — | — | |||
| GADA >10 units/mL and IA-2A 10 units/mL | 0.1 | — | 41.2 | 28.5 | — | — |
—, not reported; avg., average; DKA, diabetic ketoacidosis; IA-2A, islet antigen 2 antibody; neg, negative; pos, positive; PPV, positive predictive value; RU, relative unit; rx, prescription; T2D, type 2 diabetes; TG, triglyceride; WHO, World Health Organization.
*
Randomized to noninsulin therapy.
**
Approximate value from article figure (reported graphically only).
***
Duration not reported separately; therefore, duration for antibody positive overall provided.