Table 2—

Systematic review of the literature

StudyPatientsInterventionControlFace-to-face consultationsStudy designOutcome
Pediatric patients
 Marrero et al., 1995 (26)106 type 1 diabetic pediatric patients on multiple daily insulin injections with inadequate control.Modem transmission every 2 weeks, with clinician feedback (algorithm triggered).No scheduled intervisit contacts or data transmission.Every 3 months.Parallel RCT. No report of loss to follow-up. Outcome: HbA1c at 6 and 12 months.Telecare: Mean HbA1c (nl 6.5–8.0%) changed from 9.4% to 9.6 (6 months) and to 10.0 (12 months). Control: Changed from 9.9% to 9.7 (6 months.) and to 10.3 (12 months.). Difference: NS
Pregnant patients
 Wojcicki et al., 2001 (27)32 pregnant type 1 diabetic patients using intensive insulin therapy and with inadequate control.Nightly modem transmission, with daily clinician feedback.No scheduled intervisit contacts or data transmission.Every 3 weeks.Parallel RCT. Two patients were excluded from analysis because of illness after randomization. Outcome: HbA1c at 6 months.Telecare: Mean HbA1c (nl NR) changed from 7.9% to 6.8. Control: Changed from 8.1% to 6.7. Difference: NS
Adult patients
 Ahring et al., 1992 (24)42 type 1 diabetic patients not using intensive insulin therapy and with inadequate control.Modem transmission every week, with clinician feedbackNo scheduled intervisit contacts or data transmission.At baseline, 6 weeks, and 12 weeks.Parallel RCT. Two patients lost to follow-up from each arm. Outcome: HbA1c at 3 months.Telecare: Mean HbA1c (nl 4.5–9.0%) changed from 10.6% to 9.2. Control: Changed from 11.2% to 10.2. Difference: NS
 Gómez et al., 2002 (28)10 type 1 diabetic patients with inadequate glycemic control.Modem transmission every 2 weeks, with clinician feedback within the 24 h following each transmission.No scheduled intervisit contacts or data transmission.Every 6 months.Crossover RCT (period duration of 6 months). No data reported on loss to follow-up. Outcome: HbA1c at 6 months.Telecare: Median HbA1c (nl NR) changed from 8.4% to 7.9. Control: Changed from 8.1% to 8.2. Difference: NS
 Bierdmann et al., 2002 (22,23)48 type 1 diabetic patients using intensive insulin therapy and with inadequate control.Modem transmission at least every 2 weeks, with clinician feedback every 2 to 4 weeks.Face-to-face visits at least every month.Every 2 months.Parallel RCT. Five patients lost to follow-up at 4 months. Outcome: HbA1c at 4 months (data at 8 months available for only 21 patients).Telecare: Mean HbA1c (nl NR) changed from 8.3% to 6.9. Control: Changed from 8.0% to 7.0. Difference: NS
 Chase et al., 2003 (25)70 type 1 diabetic patients with some receiving intensive insulin therapy and with a wide range of glycemic control.Every 2 weeks, with clinician feedback.No scheduled intervisit contacts or data transmission.Every 3 months (omitting the mid-third month visit in the intervention group).Parallel RCT. Seven patients were excluded from analysis (five from the intervention arm because of failure to transmit data and three from the control arm for failure to attend the 3-month visit). Outcome: HbA1c at 6 months.Telecare: Mean HbA1c (nl 3.2–6.2%) changed from 9.0% to 8.6. Control: Changed from 8.9% to 8.6. Difference: NS
 Welch et al., 2003 (29)52 type 1 diabetic patients with poor glycemic control.Every 2 to 4 weeks, with clinician feedback.No scheduled intervisit contacts or data transmission.Every 3 months.Parallel RCT. Of 52 patients, 18 (10 from the control arm) and 28 (16 from the control arm) were lost to follow-up at 6 and 12 months, respectively. Outcome: HbA1c at 6 and 12 months.Telecare: Mean HbA1c changed from 8.9% to 8.6 (6 months) and to 8.5 (12 months). Control: Changed from 9.1% to 8.9 (6 months) and to 9.0 (12 months). Difference: NS at 6 and 12 months.
 Montori et al., 2004 (present study)31 type 1 diabetic patients using intensive insulin therapy and with inadequate control.Modem transmission at least every 2 weeks, with clinician feedback.Modem transmission at least every 2 weeks, with clinician feedback on demand.Every 3 months.Parallel RCT. Three patients lost to follow-up (two from the intervention arm). Outcome: HbA1c at 6 months.Telecare: Mean HbA1c (4.0–6.1%) changed from 9.1% to 7.8. Control: Changed from 8.8% to 8.2. Difference (after adjusting for baseline difference in HbA1c): P = 0.03.
  • nl, normal range; NR, not reported; RCT, randomized controlled trial.