Table 3.
Characteristics of data synthesis of included non-randomised controlled trials (n = 4).
| Author, Year, Study Design, Location |
Sample Size N | Population Characteristics | Participants, N, Program Name, Characteristics of Digital Intervention | Type of Diets Prescribed Intervention/Control | Primary Outcomes | Intervention/Follow-Up Period | Retention Adherence | Risk of Bias |
|---|---|---|---|---|---|---|---|---|
| Hallberg et al. (2018) Open-label, non-RCT a before-and-after study USA [41] |
N = 349 | Adults (21–65 years) with T2DM b, mean age 53.7 years (CCI e) Participants taking any diabetes medication included |
N = 262 (CCI e) IG c: Virta Health, digitally delivered via the Virta app. CG d: (N = 87) Usual diabetes care education by a dietitian |
IG c: VLCD f (<30 g/carbs per day) to induce nutritional ketosis CG d: Usual diabetes diet (low fat) |
HbA1c, body weight and medication use change | 12 months | 83% retention 25% remission |
Positive selection bias; conflict of interest |
| Athinarayanan et al. (2019) Open-label non- RCT a before-and-after study USA [40] |
N = 349 | Adults (21–65 years) with T2DM b, mean age 53.8 years (CCI e) Participants taking any diabetes medication included |
N = 262 (CCI e) IG c: Virta Health Digitally delivered via Virta app. CG d: (N = 87) Usual diabetes care education by a dietitian |
IG c: VLCD f (<30 g/carbs per day) to induce nutritional ketosis CG d: Usual diabetes diet (low fat) |
HbA1c, body weight changes and retention | 24 months | 74% retention 17.6% remission | Positive selection bias; conflict of interest |
| Summers et al. (2021) Single arm pre-post prospective real-world study/intervention UK [13] |
N = 45 | Obese adults (>18) with T2DM b or prediabetes, mean age 54.8 years Participants taking any diabetes medication included |
N = 45 The Low Carb Program—12 weeks digitally delivered. Included behavioural change techniques |
LCD g—(<130 g/carbs per day) based on visual plate representation | HbA1c and body weight change | 12 months | 82% retention | Neutral; no comparison; self-reporting outcome data; funding unclear |
| Saslow et al. (2018) Open-label single-arm, pre-post intervention USA [43] |
N = 1000 | Adults (>18) with T2DM b, mean age 56.1 years. Participants taking any diabetes medication included |
N = 1000 The Low Carb Program—10-week digitally delivered. Included behavioural change techniques |
LCD g—(<130 g/carbs per day) based on visual plate representation | HbA1c and body weight change | 12 months | 71% retention 26% remission |
Neutral; no comparison; self-reporting outcome data |
a RCT: randomized controlled trial, b T2DM: type 2 diabetes mellitus, c IG: intervention group, d CG: control group, e CCI: continuous care intervention, f VLCD: very low carbohydrate diet, g LCD: low carbohydrate diet.