Table 1.

Characteristics of study participants in included studies.

Author, year, country	Study design	Follow-up period	Population description	Intervention			Conjtrol	Baseline characteristics of patients (mean ± SD)						Outcome included in review
				Intervention setting (Community-based = 1, Primary care based = 2, Hospital setting based = 3)	Medium of communication used (Short message service = 1, Telephone = 2, Web-based = 3, Mobile phone app = 4, Video conferencing system = 5)	Telemedicine strategies (Teleconsultation = 1, Tele-education = 2, Telecase-management = 3, Telemonitoring = 4, Telementoring = 5)		N patients	Age (years)	Male sex (n or %)	BMI (kg/m2)	HbA1c	Diabetes duration
Hansel et al., 2017, France 8	Randomized trial	4 months	Patients with abdominal obesity and T2DM, HbA1c >5.6% and <8.5%	3	3	125	Usual care	60c, 60i	57 ± 9	40 (33.3%)	33 ± 4	7.2 ± 1.1	no data	HbA1c, body weight
Kim and Jeong, 2007, South Korea 9	A control group pretest–posttest design	6 months	Patients with T2DM	3	13	234	Usual care	26c, 25i	47.5 ± 9.1c, 46.8 ± 8.8i	11c, 11i	23.4 ± 2.5c, 24.5 ± 2.9i	7.59 ± 1.09c, 8.09 ± 1.72i	8.0 ± 4.9c, 5.2 ± 5.9i	HbA1c, FBG, 2HPMG
Basudev et al., 2016, United Kingdom 10	Prospective randomized controlled study	12 months	Patients with T2DM of >1 year duration and HbA1c > 69 mmol/mol (>8.5%)	1	5	134	Usual care	115c, 93i	59.3 ± 12.0c, 60.5 ± 12.3i	68 (59.6%)c, 51 (54.8%)i	31.4 ± 7.1c, 30.8 ± 6.7i	10.4 ± 1.4c, 10.2 ± 1.7i	9.4 ± 5.2c, 10.7 ± 6.8i	HbA1c, BMI
Nicolucci et al., 2015, Italy 11	A randomized, parallel group (1:1), open-label, multicenter study	12 months	Patients with T2DM HbA1c between 7.5% and 10%	1	12	24	Usual care	149c, 153i	57.8 ± 8.9c, 59.1 ± 10.3i	61.7c, 61.4i	29.0 ± 5.0c, 28.7 ± 4.6i	8.0 ± 0.8c, 7.9 ± 0.7i	8.7 ± 6.2c, .3 ± 6.2i	HbA1c, weight
Oh et al., 2003, South Korea 12	A randomized comparison experimental design	3 months	Patients with T2DM, HbA1c ⩾ 7%	3	2	124	Usual care	25c, 25i	62.0 ± 5.7c, 59.2 ± 7.2i	36.0%c, 36.0%i	24.4 ± 2.6c,24.6 ± 2.6i	8.3 ± 0.9c, 8.8 ± 1.1i	162.4 ± 8.35c, 158.1 ± 99.3i (months)	HbA1c, FBG, 2HPMG, BMI
Stone et al., 2010, USA 13	Randomized controlled trial	6 months	Patients with T2DM, HbA1c ⩾ 7.5%	12	123	124	Usual care	77c, 73i	One-third of the participants in both groups were aged 65 years	The vast majority were male	No data	9.4 ± 1.4c, 9.6 ± 1.6i	No data	HbA1c, Weight
Kim and Oh, 2003, Korea 14	Randomized controlled trial	12 weeks	Patients with T2DM, HbA1c ⩾ 7%	3	2	245	Usual care	16c, 20i	60.9 ± 5.8c, 59.7 ± 7.3i	25%c, 35%i	24.6 ± 2.8c, 24.6 ± 2.8i	8.2 ± 0.8c 8.8 ± 1.2i	13.4 ± 7.7c, 14.0 ± 8.9i	HbA1c
Khanna et al., 2014, Spanish 15	Prospective, randomized, open-label trial with blinded endpoint assessment	12 weeks	Patients with T2DM, HbA1c >8.5% (not being on insulin) and >8% (being on insulin)	1	2	124	Usual care	37c, 38i	53 ± 12c, 51 ± 12i	68%c, 50%i	33 ± 7c, 35 ± 10i	8.9 ± 1.3c, 9.2 ± 1.9i	No data	HbA1c, BMI
Cho et al., 2017, Korea 16	A randomized, prospective open trial	6 months	Patients with T2DM, HbA1c between 7% and 10%	3	3	1234	Usual care	240c, 244i	53.4 ± 8.7c, 52.9 ± 9.2i	63.3%c, 63.5%i	25.5 ± 3.2c, 25.6 ± 3.4i	7.81 ± 0.66c, 7.86 ± 0.69i	No data	HbA1c, FBG, Postprandial glucose, BMI
Welch et al., 2011, USA 17	Randomized controlled trial	12 months	Patients with T2DM, HbA1c >7.5% within the past 3 months but not >14%	12	3	2345	Usual care	21c, 25i	57.5 ± 9.5c, 54.4 ± 10.4i	38.1%c, 32%i	35.8 ± 14.0c, 33.8 ± 7.8i	8.5 ± 1.0c, 9.0 ± 1.2i	13.8 ± 7.7c, 10.3 ± 8.0i	HbA1c, BMI
Fortmann et al., 2017, USA 18	A randomized, nonblinded, parallel groups clinical trial	6 months	Patients with T2DM, HbA1c ⩾ 7.5%	2	1235	245	Usual care	63c, 63i	49.1 ± 10.6c, 47.8 ± 9.0i	15 (24%)c, 17 (27%)i	32.2 ± 6.6c, 31.5 ± 6.0i	9.6 ± 1.4c, 9.5 ± 1.2i	No data	HbA1c, FBS, BMI
Yang et al., 2020, Korea 19	Randomized controlled trial	3 months	Patients with T2DM, HbA1c between 7% and 10%	2	1234	145	Usual care	97c, 150i	60.6 ± 10.2c, 54.1 ± 10.1i	45 (46%)c, 80 (53.3%)i	25.7 ± 3.9c, 26.3 ± 3.7i	7.9 ± 0.8c, 8 ± 0.8i	No data	HbA1C, BMI
Wakefield et al., 2014, Missouri 20	A single-center randomized controlled clinical trial	3 months	Patients with T2DM, HbA1c ⩾8%	2	3	45	Usual care	55c, 53i	62.5 ± 10.9c, 57.7 ± 10.8i	41%c, 7%i	No data	7.4 ± 0.18 (n = 53)c, 7.2 ± 0.21 (n = 41)i	No data	HbA1c
Egede et al., 2018, USA 21	A randomized controlled trial	12 months	Patients with T2DM	1	25	124	Usual care	47c, 43i	62.7 ± 3.4c, 63.5 ± 4.9i	97.9%c, 97.7%i	No data	7.3 ± 2.0c, 6.9 ± 1.1i	No data	HbA1c
Steventon et al., 2014, United Kingdom 22	A large cluster randomized trial	12 months	Patients with T2DM	1	3	245	Usual care	213c, 300i	66.2 ± 11.9c, 63.9 ± 13.0i	64.3%c, 3.3%i	30.3 ± 5.9 (n = 189)c, 31.8 ± 6.6 (n = 245)i	8.3 ± 1.7c, 8.5 ± 1.8i	No data	HbA1c
Duruturk and Özköslü, 2019, Turkey 23	A double-blind randomized controlled trial	6 weeks	Patients with T2DM at least 6 months	3	5	15	Usual care	21c, 23i	53.04 ± 10.45c, 52.82 ± 11.86i	14c, 12i	29.90 ± 4.63c, 32.07 ± 6.51i	7.57 ± 0.99c, 7.14 ± 0.91i	5.23 ± 3.36c, 4.89 ± 3.86i	HbA1c
Cho et al., 2011, Korea 24	A randomized controlled trial	24 weeks	Patients with T2DM, HbA1c between 6% and 10%	3	13	4	Usual care	41c, 38i	51 ± 11c, 48 ± 13i	68%c, 63%i	24.2 ± 2.1c, 22.8 ± 2.8i	6.7 ± 0.8c, 6.9 ± 0.9i	3.3 ± 0.8c, 3.7 ± 1.0i	HbA1c
Wakefield et al., 2011, USA 25	Randomized controlled trial	12 months	Patients with T2DM	2	123	2345	Usual care	107c, 93i (High-intensity group) 102i (Low-intensity group)	67.9 ± 9.9c, 67.8 ± 10i (High-intensity group) 68.4 ± 9.5i (Low-intensity group)	96c, 99i (High-intensity group) 99i (Low-intensity group)	33.8 ± 6.9c, 33.1 ± 6.6i (High-intensity group), 33.1 ± 7.3i (Low-intensity group)	7.2c, 7.1i (High-intensity group) 7.2i (Low-intensity group)	No data	HbA1c
Kim et al., 2008, South Korea 26	Quasi-experimental design	12 months	Patients with T2DM and obese	3	123	2345	Usual care	16c, 18i	48.5 ± 8.0c, 45.5 ± 9.1i	7 (43.8%)c, 9 (50.0%)i	25.0 ± 1.7c, 25.6 ± 2.4i	7.6 ± 0.7c, 8.1 ± 1.9i	7.8 ± 5.0c, 4.6i ± 6.3i	HbA1c, FBG, 2HPMG
Katula et al., 2022, USA 27	Single-blind RCT	12 months	Patients with BMI ⩾ 25 kg/m2 (⩾22 kg/m2 if participant self-identified as Asian), and had baseline HbA1c in the prediabetic range (5.7%−6.4% (39−46 mmol/mol))	12	3	2345	Usual care	300c, 299i	55.6 ± 12.6c, 55.3 ± 12.9i	116 (38.7%)c, 115 (38.5%)i	36.1 ± 6.6c, 35.8 ± 6.1i	5.8 ± 0.2c, 5.8 ± 0.3i	No data	BMI, HbA1c
Hu et al., 2021, China 28	A randomized controlled trial	6 months	Patients with T2DM more than 3 months	3	4	14	Usual care	70c, 72i	52.21 ± 8.38c, 50.04 ± 5.76i	43c, 51i	24.05 ± 3.98c, 24.69 ± 3.39i	8.63 ± 1.62c, 8.96 ± 1.78i	6.09 ± 1.66c, 6.24 ± 1.95i	HbA1c
Warren et al., 2018, Australia 29	A prospective randomized controlled trial	6 months	Patients with T2DM, HbA1c level measured at ⩾58 mmol/mol (7.5%) at least once in the previous 12 months	1	35	134	Usual care	63c, 63i	61.3 ± 11.4c, 61.3 ± 10.8i	48%c, 60%i	34.1 (30.3–40.6)c, 34.2 (29.6–39.8)i	8.1 (7.1–8.9)c, 8.4 (7.8–9.0)i	No data	HbA1c, BMI
Cho et al., 2011, Korea 30	A randomized controlled design	3 months	Patients with T2DM, HbA1c 7.0%–11.0%	2	3	124	Usual care	35c, 36i	63.1 ± 10.3c, 5.3 ± 9.3i	34%c, 44%i	24.7 ± 3.1c, 25.2 ± 3.4i	8.0 ± 1.0c, 8.0 ± 0.8i	9.9 ± 9.6c, 7.9 ± 6.8i	HbA1c
Jia et al., 2021, China 31	A cluster randomized trial	12 months	Patients with T2DM	123	34	145	Usual care	6509c, 13037i	60.8 ± 8.4c, 60.4 ± 8.4i	2613 (40.1%)c, 5447 (41.8%)i	25.6 ± 3.6c, 25.7 ± 3.5i	7.83 ± 1.91c, 7.89 ± 1.93i	6 (3, 11)c median (Q1, Q3), 6 (3, 10)i median (Q1, Q3)	HbA1c < 7.0%, BMI
Trief et al., 2016, USA 32	Randomized clinical trial	12 months	Patients with T2DM, HbA1c ⩾ 7.5%	1	2	2	—	Diabetes education: 78 individual calls: 93 couples calls: 97	Diabetes education: 56.9 ± 10.4, individual calls: 55.6 ± 11.4, couples calls: 57.8 ± 10.8	Diabetes education: 59.0%, individual calls: 62.4%, couples calls: 62.9%	Diabetes education: 36 ± 8.1, individual calls: 36 ± 8.2, couples calls: 35.7 ± 6.3	Diabetes education: 9.1 ± 1.6, individual calls: 9.3 ± 1.7, couples calls: 8.9 ± 1.3	Diabetes education: 12.6 ± 8.3, individual calls: 11.9 ± 6.9, couples calls: 12.8 ± 8.5	HbA1c, BMI
Wayne et al., 2015, Canada 33	Pragmatic randomized controlled trial	6 months	Patients with T2DM, HbA1c ⩾ 7.3%	1	124	345	Usual care	49c, 48i	53.3 ± 11.9c, 53.1 ± 10.9i	10 (20%)c, 17 (35%)i	37.00 ± 7.92c, 33.74 ± 6.70i	8.89 ± 1.30c, 8.69 ± 1.32i	No data	HbA1c, BMI
Benson et al., 2019, USA 34	Randomized controlled trial	12 months	Patients with T2DM	23	12	125	Usual care	58c, 60i	60.0 ± 8.66c, 59.8 ± 10.20i	56.9%c, 53.3%i	36.2 ± 6.21c, 37.8 ± 9.80i	8.3 ± 1.66c, 8.1 ± 1.55i	<1 (10.3%), 1–3 (19.0%), 3–5 (15.5%), 5–10 (29.3%), >10 (25.9%)c, <1 (8.3%), 1–3 (13.3%), 3–5 (10.0%), 5–10 (25.0%), >10 (40.0%)i	HbA1c, BMI
Hee-Sung, 2007, Korea 35	A control group pretest–posttest design	12 weeks	Patients with T2DM	3	123	2345	Usual care	HbA1c <7.0%, 11c, 13i, HbA1c ⩾ 7.0%, 15c, 12i	49.2 ± 9.2c, 50.0 ± 8.6i, 46.2 ± 9.1c, 43.4 ± 7.9i	5c, 5i, 6c, 6i	23.1 ± 2.9c, 24.6 ± 2.2i, 23.6 ± 2.3c, 24.5 ± 3.6i	6.71 ± 0.39c, 6.92 ± 0.35i, 8.24 ± 0.98c, 9.35 ± 1.72i	7.8 ± 5.2c, 5.5 ± 4.8i, 8.1 ± 4.7c, 4.8 ± 7.0i	HbA1c
Xu et al., 2020, Missouri 36	A randomized controlled trial	6 months	Patients with T2DM, HbA1c > 7%	2	12	34	Usual care	32c, 33i	55.34 ± 1.94c, 54.6 ± 1.82i	25%c, 37.5%i	No data	9.23 ± 0.32c, 9.8 ± 0.45i	No data	HbA1c, FBG
Lu et al., 2021, China 37	A randomized controlled trial	6 months	Patients with T2DM, HbA1c 7%–10%	3	3	34	Usual care	59c, 60i	53.17 ± 11.44c, 56.75 ± 12.05i	55.93%c, 53.33%i	No data	9.20 ± 1.92c, 9.27 ± 2.26i	No data	HbA1c, FBG
Anderson et al., 2010, USA 38	A randomized controlled trial	12 months	Patients with T2DM	1	2	134	Usual care	149c, 146i	No data	64 (43.0%)c, 60 (41.1%)i	33.7 ± 6.64c, 35.4 ± 8.63i	8.4 ± 2.33c, 7.6 ± 1.75i	No data	HbA1c, BMI
Agarwal et al., 2019, Canada 39	Multicenter pragmatic randomized controlled trial	6 months	Patients with T2DM, HbA1c > 8.0%	23	14	234	Usual care	113c, 110i	52.1 ± 10.7c, 51.5 ± 10.6i	55 (49.0%)c, 61 (55.0%)i	no data	9.03 ± 1.53c, 8.89 ± 1.82i	No data	HbA1c
Cho et al., 2009, Korea 40	Randomized controlled trial	3 months	Patients with T2DM	1	123	12345	—	Internet group: 34, Phone group: 35	Internet group: 45.2 ± 11.3, Phone group: 51.1 ± 13.2	Internet group: 26 (76%), Phone group: 28 (80%)	Internet group: 23.6 ± 3.0, Phone group: 25.3 ± 4.7	Internet group: 7.6 ± 1.9, Phone group: 8.3 ± 2.3	Internet group: 5.3 ± 4.8, Phone group: 8.2 ± 7.8	HbA1c, FBG, 2HPMG
Quinn et al., 2016, USA 41	Randomized controlled trial	12 months	Patients with T2DM at least 6 months, HbA1c level ⩾7.5% within the past 3 months	1	1234	234	Usual care	Age < 55 years, 29c, 37i, age > 55 years, 27c, 25i	47.4 ± 7.5c, 47.4 ± 6.8i, 59.5 ± 2.8c, 59.0 ± 2.9i	62.1%c,37.8%i, 37%c, 68%i	33.9 ± 5.4c, 36.5 ± 8.3i, 34.7 ± 7.2c, 34.8 ± 4.8i	9.9 ± 1.8c, 9.9 ± 2.0i, 8.4 ± 1.2c, 9.8 ± 2.3i	8.9 ± 7.5c, 6.8 ± 4.5i, 9.2 ± 6c, 10.3 ± 5.8i	HbA1c
Sun et al., 2019, China 42	Randomized controlled trial	6 months	Patients with T2DM, HbA1c 7.0%–10.0%	3	14	2345	Usual care	47c, 44i	68.04c, 67.9i	18 (38%)c, 19 (43%)i	23.30c, 23.60i	7.88 ± 0.64c, .84 ± 0.73i	11.52 ± 7.73c, 11.19 ± 6.39i	HbA1c, BMI
Lim et al., 2016, Korea 43	Randomized, controlled clinical trial	6 months	Patients with T2DM, HbA1c 7.0%–10.5%	3	13	2345	Usual care	50c, 50i	65.8 ± 4.7c, 64.3 ± 5.2i	35c, 40i	25.4 ± 3.3c, 25.9 ± 3.6i	7.9 ± 0.8c, 8.1 ± 0.9i	14.6 ± 8.4c, 14.4 ± 9.5i	HbA1C, BMI
Tang et al., 2013, USA 44	Randomized clinical trial	12 months	Patients with T2DM ⩾18 y.o, HbA1c ⩾ 7.5% more than 1 year resulted within 30 days	123	1245	345	Usual care	213c, 202i	53.5 ± 10.2, 54.0 ± 10.7	61%, 58.9%	No data	9.28, 9.24	No data	HbA1c
Greenwood et al., 2015, USA 45	Randomized clinical trial	6 months	Patients with T2DM	1	3	1234	Usual care	45c, 45i	57.5 ± 10.6c, 53.9 ± 10.4i	79%c, 75%i	34.1 ± 6.6c, 34.1 ± 6.8i	8.2 ± 1.1c, 8.5 ± 1.1i	8.1 ± 5.3c, 8.3 ± 5.5i	HbA1c
Williams et al., 2012, Australia 46	Randomized controlled trial	6 months	Adults with type 2 diagnosis of ⩾3 months and HbA1c ⩾ 7.5%,	1	2	1234	Usual care	60c, 60i	56.4 ± 8.3c, 58.4 ± 8.2i	63.3%c, 61.7%i	No data	8.9c, 8.7i	No data	HbA1c, HRQL
Ramadas et al., 2018, Malaysia 47	Randomized clinical trial	12 months	Patients with T2DM, HbA1c ⩾ 7%	23	13	235	Usual care	62c, 66i	51.5 ± 10.3, 49.6 ± 10.7	75.8%, 62.1%	no data	8.9 ± 1.9, 9.1 ± 2.0	6.8, 9.3	HbA1c
Egede et al., 2017, United States 48	Randomized clinical trial	6 months	Patients with T2DM aged ⩾ 18 years from the southeastern United States, HbA1c ⩾ 8%	1	23	234	Usual care	59c, 54i	53.4 ± 10.5, 55.1 ± 11.4	18.6%, 18.5%	36.9 ± 9.4, 34.2 ± 7.8	10.1 ± 2.1, 10.1 ± 1.8	11.5 ± 7.2, 13.0 ± 8.1	HbA1c
Kim et al., 2016, China 49	Randomized open-label, parallel group design	6 months	T2DM Chinese patients were diagnosed ⩾ 1 year, HbA1c level of 7.0%–10.0%	3	123	1234	Usual care	90c, 92i	55.6 ± 10.0c, 52.5 ± 9.1i	43.3%c, 53.3%i	25.2 ± 3.5c, 25.8 ± 2.7i	8.0 ± 0.8c, 7.9 ± 0.7i	No data	HbA1c
Goode et al., 2015, Australia 50	A randomized trial	18 months	Patients with T2DM	1	2	14	Usual care	151c, 151i	Usual group: no data. Intervention group: Low: 57.1 ± 7.3, Medium: 59.4 ± 7.4, High: 56.8 ± 9.3	Usual group: no data. Intervention group: - Low: 29 (58.0%), Medium: 23 (50.0%), High: 32 (58.2%)	Usual group: no data. Intervention group: Low: 32.4 ± 6.3, Medium: 33.7 ± 7.1, High: 33.2 ± 5.5	Usual group: no data. Intervention group: Low: 6.9 ± 7.93. Medium: 7.3 ± 8.33, High: 7.1 ± 7.9	Usual group: no data. Intervention group: Low: 4 ± 6.3, Medium: 4.5 ± 2, 7.3. High: 4 ± 10	HbA1c
Jeong et al., 2018, Korea 51	Randomized clinical trial	24 weeks	Patients with T2DM, HbA1c from 7% to 11%	3	1235	12345	Usual care	113c, 113i, 112i	53.16 ± 9.06, 53.65 ± 9.10, 52.46 ± 8.48	67.26%, 66.37%, 68.75%	25.39 ± 3.07, 25.22 ± 3.64, 25.21 ± 3.27	8.39 ± 1.10, 8.21 ± 0.93, 8.39 ± 1.10	No data	HbA1c
Nagrebetsky et al., 2013, United Kingdom 52	Feasibility trial	12 months	Patients with T2DM, HbA1c 8%–11%	2	123	45	Usual care	9c, 8i	60 ± 13, 56 ± 8	71%, 71%	32.4 ± 6.2, 33.4 ± 7.1	66 ± 13 mmol/mol, 64 ± 11 mmol/mol	2.3, 3.0	HbA1c
Wild et al., 2016, United Kingdom 53	Randomized clinical trial	9 months	Patients with T2DM aged > 17 years, HbA1c > 58 mmol/mol.	2	23	134	Usual care	161c, 160i	61.4 ± 9.8, 60.5 ± 9.8	66.2%, 67.1%	31.9 ± 6.3, 33.8 ± 7.0	8.8 ± 1.1, 8.9 ± 1.3	7.4 ± 5.8, 7.4 ± 5.7	HbA1c
de Vasconcelos et al., 2018, Brazil 54	Randomized clinical trial	24 weeks	Patients with T2DM for at least 1 year	2	2	1235	Usual care	15c, 16i	59.6, 60.9	5, 2	29.87 ± 5.25, 29.99 ± 5.82	6.9 ± 1.31, 8.0 ± 2.14	8.67 ± 6.39, 10 ± 8.48	HbA1c, BMI
Rasmussen et al., 2016, Denmark 55	Randomized controlled trial	6 months	Patients with T2DM	3	5	1	Usual care	22c, 18i	64.6c, 60.7i	14 (63.6%)c, 13 (72.2%)i	30.4c, 32.6i	8.1c, 9.0i	8.4c, 10.7i	HbA1c, Blood glucose level, Weight
Rodríguez-Idígoras et al., 2009, Spain 56	Randomized controlled parallel-group trial	1 year	Patients with T2DM	2	234	234	Usual care	167c, 161i	64.52, 63.32	49.10%, 54.04%	No data	7.41, 7.62	10.18, 11.32	HbA1c
von Storch et al., 2019, Germany 57	Prospective study	3 months	Patients with T2DM	2	2	1345	Usual care	55c, 60i	58.4 ± 7.3, 59.4 ± 6.3	85% 78%	29.3 ± 4.43, 31.9 ± 7.06	6.89 ± 1.01, 7 ± 0.96	7± 4.1, 7± 4	HbA1c, BMI
Lee et al., 2020, Malaysia 58	Cluster-randomized controlled trial	52 weeks	Patients with T2DM	2	2	234	Usual care	120c, 120i	56.3 ± 8.6, 56.1 ± 9.2	45.8%, 44.2%	No data	9.00, 9.00	6.6 ± 7.0, 6.7 ± 5.3	HbA1c
Lee et al., 2017, Malaysia 59	Cluster-randomized controlled trial	12 weeks	Patients with T2DM, HbA1c between 7.5% and 11.0%	12	134	234	Usual care	40c, 45i	53.77 ± 8.03c, 53.24 ± 7.29i	16 (40.00%)c, 24 (60.00%)i	30.28 ± 5.05c, 29.20 ± 5.98i	8.79 ± 1.15c, 8.69 ± 1.12i	10.04 ± 7.64c, 7.91 ± 4.81i	HbA1c, BMI
Dario et al., 2017, Italy 60	Randomized controlled trial	12 months	Patients with T2DM, HbA1c > 7.0%	1	4	4	Usual care	91c, 208i	73.04 ± 5.28c, 73.05 ± 5.79i	49 (53%)c, 119 (57%)i	No data	7.93 ± 1.10c, 7.94 ± 0.98i	16.01 ± 9.84, 15.01 ± 10.24	HbA1c
Egede et al., 2017, USA 61	Randomized controlled trial	4 years	Patients with T2DM, HbA1c ⩾ 9%	23	2	12345	Usual care	64c, 63i (knowledge), 65i (skills) 63i (combination)	56.1 ± 10.3c, 56.5 ± 11.5i, 58.3 ± 9.5i, 58.2 ± 10.0i	51.6%c, 55.6%i, 61.5%i, 52.4%i	No data	9.5 ± 2.5c, 9.3 ± 1.8i, 9.2 ± 2.1i, 9.2 ± 1.9i	13.5 ± 9.3c, 12.5 ± 8.3i, 13.5 ± 8.8i, 13.7 ± 9.7i	HbA1c
Bujnowska-Fedak et al., 2011, Poland 62	Randomized clinical trial	6 months	Patients with T2DM	2	124	4	Usual care	48c, 47i	57.5 ± 27.4, 53.1 ± 25.2	25, 26	26.2 ± 6.6, 25.4 ± 7.2	7.61 ± 1.65, 7.63 ± 1.53	7.7 ± 6.8, 8.1 ± 7.6	HbA1c
Arora et al., 2014, United States 63	Randomized controlled trial	6 months	Patients with T2DM, HbA1c ⩾ 8%	3	1	23	Usual care	64c, 64i	51.0 ± 10.2, 50.5 ± 10.3	20, 26	No data	10.0 ± 1.7, 10.2 ± 1.7	10.1 ± 6.5 10.9 ± 10.4	HbA1c
Kardas et al., 2016, Poland 64	A feasibility prospective parallelarm randomized controlled trial	6 weeks	Patients with T2DM	2	45	34	Usual care	30c, 30i	59.0 ± 8.09c, 59.9 ± 5.31i	19 (63.3%)c, 17 (56.7%)i	30.3 ± 3.35c, 31.6 ± 5.27i	6.84 ± 0.98c, 6.78 ± 1.10i	No data	FBG, HbA1c
McFarland et al., 2012, USA 65	Nonrandomized, parallel, control group study	6 months	Patients with T2DM, HbA1c ⩾ 7%	12	12	34	Usual care	67i, 36c	63 ± 10c, 66 ± 9i	64 (96%)c, 36 (100%)i	No data	9.1 ± 1.6c, 9 ± 1.5i	No data	HbA1c
Hansen et al., 2017, Denmark 66	Cross-sectional randomized controlled trial	8 months	Patients with T2DM, HbA1c > 7.5%	13	5	134	Usual care	82c, 83i	58.3 ± 9.3c, 57.8 ± 9.4i	53 (65%)c, 53 (64%)i	33.6 ± 5.6c, 33.9 ± 6.2i	9.36 ± 1.3c, 9.25 ± 1.2i	12.5 ± 7.3c, 12.1 ± 6.6i	HbA1c
Zhou et al., 2014, China 67	Prospective randomized study	3 months	Patients with T2DM	3	123	234	Usual care	55c, 53i	No data	No data	23.64 ± 3.01, 24.72 ± 3.38	8.22 ± 1.58, 8.44 ± 1.58	No data	FBG, HbA1c
Luley et al., 2011, Germany 68	Randomized clinical trial	6 months	Patients with T2DM with BMI > 25 kg/m2	1	2	45	Usual care	35c, 35i	58 ± 7, 57 ± 9	54%, 43%	34.8 ± 5.9, 35.3 ± 5.7	7.6 ± 1.1, 7.5 ± 1.1	No data	HbA1c, BMI
Hsu et al., 2016, USA 69	A randomized controlled study	12 ± 2 weeks	Patients with T2DM, HbA1c levels of 9%–14%	1	3	234	Usual care	20c, 20i	53.8c, 53.3i	No data	31.7c, 30.8i	10.9c, 10.8i	9c, 9.6i	HbA1c
Kleinman et al., 2017, India 70	A randomized clinical trial	6 months	Patients with T2DM, HbA1c levels between 7.5% and 12.5%	3	34	4	Usual care	46c, 44i	48.0 ± 9.5c, 48.8 ± 9.0i	58.7%c, 81.8%i	28.0 ± 4.2c, 29.7 ± 6.0i	9.1 ± 1.1c, 9.4 ± 1.2i	8.5c, 10.0i	HbA1c, FBG, BMI
Orsama et al., 2013, Finland 71	A randomized controlled trial	10 months	Patients with T2DM, HbA1c levels 6.5% and 11%	1	124	234	Usual care	24c, 24i	61.5 ± 9.1c, 62.3 ± 6.5i	54%c, 54%i	33.5 ± 8.0c, 30.7 ± 4.5i	7.09 ± 1.51c, 6.86 ± 1.56i	No data	HbA1c, weight
Kim et al., 2007, Korea 72	A randomized controlled trial	12 weeks	Patients with T2DM	3	123	123	Usual care	26c, 25i	47.5 ± 9.1c, 46.8 ± 8.8i	11c, 11i	23.4 ± 2.5c, 24.5 ± 2.9i	7.59 ± 1.09c, 8.09 ± 1.72i	8.0 ± 4.9c, 5.2 ± 5.9i	HbA1c, 2HPMG
Bender et al., 2017, USA 73	A randomized controlled trial	6 months	Patients with T2DM and BMI > 23 kg/m2	1	34	245	Usual care	23c, 22i	57.7 ± 10.0c, 57.4 ± 0.8i	40%c, 37%i	31.5 ± 5.1c, 28.6 ± 3.6i	7.44 ± 0.93c, 7.39 ± 0.82i	No data	HbA1c, Fasting glucose, BMI, weight
Blackberry et al., 2013, Australia 74	Prospective, cluster randomized controlled trial	18 months	Patients with T2DM, HbA1c > 7.5% in the past 12 months	1	2	25	Usual care	237c, 236i	61.9 ± 10.5c, 63.6 ± 10.4i	142 (60%)c, 127 (54%)i	No data	8.13 ± 1.34c, 7.98 ± 1.22i	9c,10i	HbA1c, weight
Borhani et al., 2013, Kerman 75	A quasi-experimental study	3 months	Patients with T2DM, HbA1c > 7%	1	2	35	Usual care	25c, 25i	No data	No data	30.69 ± 6.67c, 27.93 ± 4.84i	9.38 ± 1.53c, 9.98 ± 1.34i	No data	HbA1c, FBS, postprandial glucose, BMI
Faridi et al., 2008, USA 76	A pilot controlled trial	3 months	Patients with T2DM, BMI > 25, HbA1c < 8%	2	1	35	Usual care	15c, 15i	56.7 ± 10.6c, 55.3 ± 8.7i	33.3%c, 40%i	36.9 ± 12.5c, 34.3 ± 7.4i	6.5 ± 0.7c, 6.4 ± 0.6i	No data	HbA1c, BMI, weight
Hallberg et al., 2018, USA 77	An open-label, nonrandomized, controlled, before-and-after 1-year study	1 year	Patients with T2DM	1	34	235	Usual care	87c, 262i	52.33 ± 9.52c, 53.75 ± 8.35i	No data	36.72 ± 7.26c, 40.43 ± 8.81i	7.64 ± 1.76c, 7.60 ± 1.50i	7.85 ± 7.32c, 8.44 ± 7.22i	HbA1c, weight
Holmen et al., 2014, Norway 78	A 3-arm prospective randomized controlled trial	12 months	Patients with T2DM, HbA1c level ⩾ 7.1%	1	124	345	Usual care	50c, few touch application: 51i FTA-health counseling: 50i	55.9 ± 12.2c, 58.6 ± 11.8i, 57.4 ± 12.1i	60%c, 50%i, 67%i	32.0 ± 6.0c, 32.4 ± 6.5i, 30.7 ± 5.6i	8.3 ± 1.2c, 8.1 ± 1.1i, 8.2 ± 1.1i	9.4 ± 5.5c, 11.2 ± 7.3i, 9.6 ± 8.4i	HbA1c, weight
Lim et al., 2011, Korea 79	A randomized controlled trial	6 months	Patients with T2DM, A1C level was 6.5%–10.5%	2	123	12345	Usual care	52c, clinical decision support system (CDSS)-based ubiquitous healthcare: 51i self-monitored blood glucose: 51i	68.1 ± 5.5c, 67.2 ± 4.1i, 67.2 ± 4.4i	19c, 23i, 22i	25.4 ± 3.3c, 24.7 ± 2.3i, 24.9 ± 3.0i	7.9 ± 0.8c, 7.8 ± 1.0i, 7.9 ± 0.9i	15.8 ± 10.7c, 14.1 ± 10.1i, 15.4 ± 8.3i	HbA1c
Odnoletkova et al., 2016, Belgium 80	A parallel-group, randomized controlled trial	18 months	Patients with T2DM	1	2	12345	Usual care	287c, 287i	62.4 ± 8.9c, 63.8 ± 8.7i	63%c, 60%i	30.6 ± 5.2c, 30.2 ± 4.9i	7.0 ± 1.0c, 7.0 ± 1.1i	No data	HbA1c, BMI
Quinn et al., 2011, USA 81	A cluster-randomized clinical trial	12 months	Patients with T2DM, HbA1c level ⩾ 7.5% (within 3 months)	2	3	45	Usual care	56c, coach-only: 23i coach PCP portal: 22i coach PCP portal with decision support: 62i	53.2 ± 8.4, 52.8 ± 8.0i, 53.7 ± 8.2i, 52 ± 8.0i	50%c, 52.2%i, 45.5%i, 50%i	34.3 ± 6.3c, 36.9 ± 7.5i, 35.5 ± 10.3i, 35.8 ± 7.1i	9.2 ± 1.7c, 9.3 ± 1.8i, 9.0 ± 1.8i, 9.9 ± 2.1i	9.0 ± 7.0c, 7.7 ± 5.6i, 6.8 ± 4.9i, 8.2 ± 5.3i	HbA1c
Rothman et al., 2005, USA 82	A randomized controlled trial	12 months	Patients with T2DM, HbA1c level ⩾ 8.0%	2	2	245	Usual care	105c, 112i	57 ± 11c, 54 ± 13i	44%c, 44%i	34 ± 8c, 35 ± 9i	11 ± 3c, 11 ± 2i	9 ± 9c, 8 ± 9i	HbA1c
Varney et al., 2014, Australia 83	A random controlled trial	12 months	Patient with T2DM and HbA1c level >7%	2	2	245	Usual care	47c, 47i	64c, 59i	64%c, 72%i	30.9c, 32.1i	8.5c, 8.2i	13.1c, 12.6i	HbA1c, BMI
Waki et al., 2014, Japan 84	A nonblinded randomized controlled study	3 months	Patient with T2DM	1	13	4	Usual care	27c, 27i	57.4 ± 9.4c, 57.1 ± 10.2i	21c, 20i	27.1 ± 7.6c, 26.2 ± 6.1i	7.0 ± 0.9c, 7.1 ± 1.0i	No data	HbA1c, FBS, BMI
Wang et al., 2019, China 85	A random controlled trial	6 months	Patient with T2DM and HbA1c level >7%	3	4	1234	Usual care	60c, 60i	45.8 ± 8.38c, 45.13 ± 7.83i	31c, 33i	No data	8.68 ± 2.26c, 8.62 ± 2.33i	No data	HbA1c, FBG, 2HPMG
Kusnanto et al., 2019, Indonesia 86	A randomized experimental study	3 months	Patient with T2DM and HbA1c level >7%	1	4	45	Usual care	15c, 15i	No data	40%c, 46.7%i	No data	8.18 ± 1.02c, 8.74 ± 1.34i	No data	HbA1c
Yoo et al., 2009, Korea 87	A randomized, controlled clinical trial	3 months	Patient with T2DM, HbA1c 6.5%–10.0% and BMI ⩾ 23.0 kg/m2	13	13	4	Usual care	54c, 57i	59.4 ± 8.4c, 57.0 ± 9.1i	64.8c, 52.6i	25.5 ± 3.3c, 25.6 ± 3.5i	7.4 ± 0.9c, 7.6 ± 0.9i	7.2 ± 6.0c, 6.0 ± 5.4i	HbA1c
Meigs et al., 2003, USA 88	A group randomized controlled trial	12 months	Patient with T2DM	3	3	23	Usual care	291c, 307i	67 ± 12c, 68 ± 12i	50.5%c, 44.9%i	No data	No data	9.7 ± 5.6c, 9.9 ± 5.5i	HbA1c
Tutino et al., 2017, China 89	A multicenter randomized nonblinded study	12 months	Patient with T2DM	3	3	23	—	DIAMOND: 1728i, JADE: 1858i	56.8 ± 11.7i, 56.1 ± 11.6i	54.5%i, 54.4i%	25.32 ± 3.62i, 25.18 ± 3.58i	7.91 ± 2.08i, 7.78 ± 1.95i	5i, 5i	HbA1c
Graziano et al., 2009, USA 90	A randomized controlled trial	3 months	Patient with T2DM and HbA1c level ⩾ 7%	2	12	24	Usual care	58c, 61i	63.0 ± 9.3c, 60.1 ± 7.4i	33c, 33i	no data	8.59 ± 1.96c, 8.71 ± 1.74i	12.2 ± 8.2c, 13.5 ± 8.4i	HbA1c
Middleton et al., 2021, Australisa 91	A randomized controlled trial	12 months	Patient with T2DM	3	1	123	Usual care	19c, 21i	32.4 ± 4.4c, 33.0 ± 5.8i	53%c, 48%i	31.6 ± 5.1c, 31.8 ± 8.6i	7.3 ± 2.1c, 7.2 ± 1.6i	5.0 ± 5.9c, 7.6 ± 6.2i	HbA1c, BMI
Smith et al., 2008, USA 92	A randomized controlled trial	12 months	Patient with T2DM	2	12	12	Usual care	227c, 358i	60c, 62i	50%c, 45%i	34c, 33i	7.3c, 7.3i	4c, 4i	HbA1c
Farmer et al., 2021, UK 93	Two parallel-arm, individually randomized controlled trial	12 months	Patient with T2DM	12	1	2	Usual care	561c, 558i	no average	30.1%c, 30.1%i	30.8 ± 7.4c, 30.6 ± 6.5i	10.2 ± 3.6c, 10.1 ± 3.4i	5.2c, 5.0i	HbA1c
Vinitha et al., 2019, India 94	A multicentric, randomized controlled trial	24 months	Patient with T2DM	1	1	25	Usual care	122c, 126i	44.1 ± 8.9c, 42.4 ± 8.5i	82c, 86i	27.3 ± 4.7c, 27.2 ± 4.5i	9.5 ± 1.9c, 9.5 ± 2.1i	no data	HbA1c, FBG
Peimani et al., 2016, Iran 95	A three-arm randomized controlled trial	3 months	Patient with T2DM	2	1	25	Usual care	50c, Tailored-SMS group: 50i, Non-tailored-SMS group: 50i	54.56 ± 9.88c, 49.78 ± 9.76i, 53.26 ± 10.49i	26c, 27i, 28i	27.92 ± 4.97c, 27.71 ± 5.29i, 27.40 ± 4.73i	7.52 ± 1.49c, 7.29 ± 1.33i, 7.53 ± 1.47i	9.98 ± 7.51c, 8.09 ± 6.95i, 8.9 ± 6.63	HbA1c, FBS, BMI
Schillinger et al., 2009, USA 96	A three-arm practical clinical trial	12 months	Patient with T2DM and HbA1C ⩾ 8.0%	12	12	2	Usual care	114c, ATSM: 112i, GMV: 113i	55.8 ± 11.8c, 55.9 ± 12.7i, 56.5 ± 11.4i	44.7%c, 42%i, 36.3%i	32.3 ± 13.5c, 30.3 ± 6.7i, 31.9 ± 8.2i	9.8 ± 2.0c, 9.3 ± 1.8i, 9.4 ± 2.0i	10.4 ± 8.1c, 9.1 ± 7.3i, 9.2 ± 6.8i	HbA1c
Kim et al., 2014, Korea 97	Clinical trial	3 months	Patient with T2DM and HbA1C was 7.0%–10.0%	3	4	13	Usual care	35c, 35i	53.8 ± 9.0c, 51.8 ± 10.3i	20c, 20i	24.9 ± 3.4c, 25.0 ± 3.3i	7.7 ± 0.5c, 7.7 ± 0.7i	, 11.8 ± 7.3i	HbA1c, BMI
Iljaž et al., 2017, Slovenia 98	A randomized controlled trial	6 months	Patient with T2DM	2	4	124	Usual care	62c, 58i	54.7c, 56.3i	36c, 37i	no data	6.8 ± 1.2c, 7.1 ± 1.5i	5.7 ± 4.8c, 5.1 ± 5.7i	HbA1c
Kwon et al., 2004, Korea 99	A randomized controlled trial	3 months	Patient with T2DM	2	13	1234	Usual care	55c, 55i	54.7 ± 9.4c, 53.5 ± 8.8i	32c, 35i	23.9 ± 3.1c, 24.4 ± 3.4i	7.19 ± 1.17c, 7.59 ± 1.43i	6.6 ± 5.7c, 7.0 ± 6.3i	HbA1c
Lee et al., 2017, Korea 100	A subanalysis of clinical trial	6 months	Patient with T2DM and HbA1c ⩾7.5%	1	2	14	Usual care	91c, infrequent users: 54i, frequent users: 53i	56.4 ± 8.7c, 53.5 ± 9.6i, 55.8 ± 9.i9	55c, 32i, 35i	35.5 ± 6c, 35.5 ± 6.5i, 34.1 ± 6.4i	9.2 ± 1.5c, 9.4 ± 1.4i, 9.2 ± 1.4i	No data	HbA1c, BMI
Kim et al., 2010, Korea 101	Clinical trial	12 weeks	Patient with T2DM and HbA1c was >7.0% and <12.0%, body mass index values <35 kg/m2	1	13	2	Usual care	45c, 47i	49.0 ± 10.7c, 47.8 ± 9.6i	22c, 24i	24.4 ± 3.5c, 23.6 ± 2.5i	9.8 ± 1.2c, 9.8 ± 1.3i	8.4 ± 6.2c, 8.5 ± 6.4i	HbA1c
Song et al., 2009, Korea 102	A randomized two-group pretest/posttest experimental study	12 weeks	Patient with T2DM	1	2	124	Usual care	25c, 24i	49.5 ± 10.6c, 51.0 ± 11.3i	50%c, 36%i	25.5 ± 3.7c, 24.2 ± 3.9i	9.0 ± 1.2c, 9.4 ± 1.8i	5.0 ± 5.7c, 4.9 ± 5.3i	HbA1c
McKay et al., 2002, USA 103	A randomized design study	3 months	Patient with T2DM	2	23	125	Usual care	Information-only condition: 40c, peer support condition: 40i, personal self-management coach condition: 40i, combined condition: 40i	60.8 ± 9.1c, 57.6 ± 9.2i, 57.6 ± 9.0i, 62.1 ± 9.5i	47.5%c, 52.5%i, 42.5%i, 45.0%i	No data	7.2 ± 1.36c, 7.64 ± 1.71i, 7.75 ± 1.33i, 7.46 ± 1.35i	11.85 ± 6.8c, 11.72 ± 8.71i, 10.00 ± 6.39i, 11.60 ± 9.23i	HbA1c
Cho et al., 2006, Korea 104	A randomized controlled trial	30 months	Patient with T2DM	2	3	24	Usual care	40c, 40i	54.6 ± 8.6c, 51.3 ± 9.1i	57.5%c, 65%i	23.8 ± 2.8c, 22.8 ± 2.6i	7.5 ± 1.3c, 7.7 ± 1.5i	6.9 ± 5.7c, 6.7 ± 5.3i	HbA1c
Eakin et al., 2013, Australia 105	A two-arm randomized controlled trial	6 months	Patient with T2DM and BMI ⩾ 25.0 kg/m2	1	2	14	Usual care	151c, 151i	58.3 ± 9.0c, 57.7 ± 8.1i	57%c, 55.6%i	33.2 ± 6.0c, 33.1 ± 6.3i	7.5 ± 1.7c, 7.4 ± 1.5i	5c, 4i	HbA1c, weight
Agboola et al., 2016, USA 106	A randomized controlled trial	6 months	Patient with T2DM and HbA1c > 7%	1	12	245	Usual care	62c, 64i	52.6 ± 12.6c, 50.3 ± 10.5c	40%c, 56%i	No data	8.38 ± 1.37c, 9.02 ± 1.63i	No data	HbA1c
Glasgow et al., 2012, USA 107	A patient-randomized practical effectiveness trial	12 months	Patient with T2DM and BMI ⩾ 25.0 kg/m2	2	23	12	Usual care	EUC: 132c, CASM: 169i, CASM+: 162i	58.7 ± 9.1c, 58.7 ± 9.3i, 57.8 ± 9.3i	48.5%c, 55.4%i, 46.3%i	34.8 ± 0.6c, 34.9 ± 0.4i, 34.9 ± 0.4i	8.16 ± 0.16c, 8.14 ± 0.10i, 8.14 ± 0.10i	No data	HbA1c, BMI
Ralston et al., 2009, USA 108	A pilot randomized trial	12 months	Patient with T2DM and HbA1c ⩾ 7%	2	3	35	Usual care	41c, 42i	57.6c, 57.0i	48.8%c, 52.4%i	No data	7.9c, 8.2i	No data	HbA1c
Noh et al., 2010, Korea 109	A randomized controlled trial	6 months	Patient with T2DM and HbA1c was ⩾7.0% and ⩽10.0%	3	3	234	Usual care	20c, 20i	42.3 ± 7.6c, 42.5 ± 10.6i	75%c, 80%i	24.7 ± 2.8c, 25.7 ± 3.1i	8.6 ± 1.2c, 9.0 ± 2.3i	8.4 ± 5.9c, 4.6 ± 6.9i	HbA1c
Murray et al., 2017, England 110	A multicenter, two-arm individually randomized controlled trial	12 months	Patient with T2DM	1	123	1245	Usual care	189c, 185i	64.7 ± 9.1c, 64.7 ± 9.1i	69%c, 69%i	29.6 ± 5.2c, 30.1 ± 5.3i	7.35 ± 1.37c, 7.26 ± 1.25i	No average	HbA1c
Bingham et al., 2021, USA 111	A retrospective study	3 months	Patients with T2DM	1	2	234	No control	444	70 [40-75]	180 (40%)	No data	7.4 [4.5-13.9]	No data	HbA1c
Michaud et al., 2020, Nebraska 112	Retrospective observational study	3 months	Patients with T2DM	3	2	234	No control	1103	60.5 ± 11.4	0.45	No data	7.6 ± 1.9	No data	HbA1c
Kesavadev et al., 2012, India 113	A retrospective cohort study	6 months	Patients with T2DM, HbA1c ⩾ 6.5%	1	23	134	No control	1000	53.2 ± 9.8	0.64	25.4 ± 3.8	8.5 ± 1.4	10.9 ± 7.1	HbA1c, FBS, BMI
Su et al., 2019, USA 114	Cohort study	3 months	Patients with T2DM	3	2	14	No control	1354	59.6 ± 11.8	45.1%	BMI ⩾ 30 kg/m2: 74.2%	7.7 ± 2.0	No data	HbA1c
Musacchio et al., 2011, Italy 115	Cohort study	12 months	Patients with T2DM	2	13	234	No control	1004	66.6 ± 9.5	54.1%	29.5 ± 4.8	6.9 ± 0.9	10.8 ± 7.7	HbA1c
Turner et al., 2009, USA 116	Exploratory study	3 months	HbA1c >7.5% commencing treatment with a basal insulin regimen during the past 12 months	2	124	35	No control	23	57.6 ± 12.0	18 (78%)	33.2 ± 6.3	9.5 ± 2.2	6.4 ± 4.5	HbA1c
Bergenstal et al., 2021, USA 117	Cohort study	17 months	Patients with T2DM	1	45	1245	No control	594	53.0 ± 8.4	224	35.4 ± 7.7 (n = 550)	7.7 ± 1.6 (n = 563)	No data	HbA1c
Michaud et al., 2018, USA 118	Retrospective, observational study	3 months	Patients with type 2 diabetes	1	2	2345	No control	955	No data	432 (45%)	35.59 ± 7.79	7.91 ± 2.07	No data	HbA1c, BMI
Cheng et al., 2021119	Cross-sectional study	1-month	Patients with T2DM	1	12	1234	Usual care	207c, 168i	64.9 ± 13.1c, 66.9 ± 12.0i	99 (47.8%)c, 76 (45.2%)i	25.8 ± 4.8c, 25.9 ± 4.2i	9.3 ± 2.3c, 9.1 ± 2.2i	No data	FBS, 2HPMG, Glucose variability
Shane-McWhorter et al., 2014, USA 120	A nonrandomized prospective observational preintervention–postintervention study	6 months	Patients with T2DM, HbA1c level >7%	2	12	245	No control	95	No data	40	No data	9.73	No data	HbA1c
Yu et al., 2014, Canada 121	A single-arm pre–post cohort study	9 months	Patients with T2DM, HbA1c > 7.0%	2	123	25	—	Observational cohort: 81. Qualitative study: 21	No average	Observational cohort: 54%, Qualitative study: 43%	No data	Observational cohort: 7.64 ± 1.29, Qualitative study: 7.17 ± 0.98	No average	HbA1c
Berman et al., 2018, USA 122	Cohort study	12 weeks	Patients with T2DM, HbA1c > 6.5%	1	24	125	No control	118	50.7 ± 9.4	18.6%	38.1 ± 8.8	8.1 ± 1.6	1.4 ± 0.9	HbA1c
Shane-McWhorter et al., 2015, USA 123	Cohort study	6 months	Patients with T2DM	1	123	1245	Usual care	75c, 75i	50.57 ± 11.01c, 48.28 ± 10.62i	33.3%c, 34.7%i	33.29 ± 6.95c, 33.13 ± 6.79i	9.44 ± 1.72c, 9.87 ± 2.06i	No data	HbA1c
Dixon et al., 2020, United States 124	Technology report	6 months	Patients with T2DM	1	1245	12345	No control	740	53.8 ± 8.8	0.37	35.6 ± 8.5	7.7 ± 1.7	No data	HbA1c
Majithia et al., 2020, USA 125	Prospective single-arm study	4 months	Patients with T2DM, HbA1c from 8% to 12%	1	4	12345	No control	55	57.3 ± 11.6	33 (60%)	33.7 ± 7.2	8.9 ± 1.0	No data	HbA1c
Kim et al., 2006, Korea 126	Pre–posttest	12 weeks	Patients with T2DM	3	13	234	No control	33	43.5 ± 12.6	42.4%	24.3 ± 3.7	8.1 ± 2.1	5.6 ± 5.7	HbA1c
Mayes et al., 2010, USA 127	Pre–posttest	3.5 years	T2DM Hispanic patients	2	245	123	No control	16	51 ± 2.5	0.19	no data	9.6 ± 0.6	No data	HbA1c
McGloin et al., 2020, Ireland 128	An observational, pre–post, multimethod, and triangulation design	12 weeks	Patients with T2DM and commencing with insulin therapy	1	2	4	No control	39	62.4	0.59	30.16 ± 7.32	9.62	No data	HbA1c, BMI
Bollyky et al., 2018, USA 129	Pre–post test	12 months	T2DM, HbA1c > 7.5%, BMI ⩾ 25	1	12	125	No control	330	50.3 ± 9.6	146 (44.2%)	No data	7.5 ± 1.9 %	No data	HbA1c
McGloin et al., 2015, Ireland 130	A longitudinal mixed-method case study	12 months	Patient with T2DM	1	2	5	No control	10	54.5 ± 6.9	0.5	34.5 ± 6.9	7.85 ± 1.98	6.5 ± 6.3	HbA1c
Carter et al., 2011, USA 131	Not reported	9 months	Patients with T2DM	2	35	24	Usual care	21c, 26i	49c, 52i	9c, 8i	36.1c, 35.4i	8.8c, 9.0i	No data	HbA1c, BMI, weight
King et al., 2009, USA 132	Initial pilot program	12 months	Patients with T2DM	2	2	124	Usual care	101c, 34i	61.0 ± 13.7c, 62.8 ± 14.0i	46.5%c, 48.5%i	No data	7.8 ± 1.9c, 7.0 ± 1.1i	No data	HbA1c
Carallo et al., 2015, Singapore 133	Not reported	1 year	Patients with T2DM	3	2	1	Usual care	208c, 104i	61.4 ± 11.2c, 63.9 ± 9.3i	62c, 63i	30.6 ± 5.8c, 31.0 ± 4.8i	61 ± 7 mmol/molc, 58 ± 6 mmol/moli	No data	HbA1c
Chen et al., 2011, Taiwan 134	Not reported	1 year	Patients with T2DM, HbA1c >7% more than 1 year	23	124	2345	Usual care	32c, 32i	55.8 ± 17.5, 51.8 ± 15.8	43.8%, 46.9%	No data	9.6 ± 1.5, 9.5 ± 1.8	15.1 ± 9.5, 12.3 ± 7.2	HbA1c
Myers et al., 2021, USA 135	Pilot study	3 months	Patients with T2DM, HbA1c ⩾ 9%	1	125	124	—	Telephone: 13, Telehealth: 9	Telephone: 58.69 ± 11.80, Telehealth: 56.56 ± 7.97	Telephone: 5, Telehealth: 5	No data	Telephone: 11.1, Telehealth: 10.3	No data	HbA1c
Istepanian et al., 2014, Iraq 136	Case study	6 months	Patients with T2DM first year	2	24	4	Usual care	6c, 6i	55.2 ± 10.1, 54.8 ± 12.7	No data	26.0 ± 3.5, 26.8 ± 3.1	8.95 ± 2.17, 8.95 ± 0.73	9.7 ± 9.4, 10.7 ± 11.3	HbA1c
Lim et al., 2009, Korea 137	Not reported	3 months	Patients with T2DM	1	2	124	Usual care	34c, 67i	58.0 ± 1.0c, 59.0 ± 1.3i	49.3%c, 44.1%i	24.8 ± 0.6c, 24.4 ± 0.4i	8.5 ± 0.3c, 8.0 ± 0.2i	8.6 ± 1.4c, 7.1 ± 0.7i	HbA1c, BMI, FBS
Yoon et al., 2008, Korea 138	Not reported	12 months	Patients with T2DM	2	13	24	Usual care	26c, 25i	47.5 ± 9.1c, 46.8 ± 8.8i	42.3%c, 0.44%i	23.4 ± 2.5c, 24.5 ± 2.9i	7.59 ± 1.09c, 8.09 ± 1.72i	8.0 ± 4.9c, 5.2 ± 5.9i	HbA1c
Nesari et al., 2010, Iran 139	Not reported	3 months	Patients with T2DM, HbA1c >7%	1	2	123	Usual care	30c, 30i	51 ± 8.2c, 51.9 ± 7.6i	20%c, 36.7%i	28.21 ± 4.70c, 28.23 ± 4.01i	9.60 ± 1.56c, 8.90 ± 1.44i	No average	HbA1c
McIlhenny et al., 2011, USA 140	Not reported	6 months	Patients with T2DM	1	3	124	Usual care	50c, 48i	61.8 ± 10.88c, 65.8 ± 14.04i	48%c, 54%i	No data	7.44 ± 1.65c, 7.12 ± 1.61i	No data	HbA1c, weight
Kim et al., 2006, Korea 141	Not reported	12 weeks	Patients with T2DM, HbA1c was < 10%, FBS <240 mg/dL	2	3	145	Usual care	23c, Web-based: 28i, Printed-material: 22i	No data	No data	No data	7.87 ± 1.52c, Web-based: 7.99 ± 1.22i, Printed-materia: 7.51 ± 1.40i	No data	HbA1c, FBS