Summary of study characteristics
| Author(s) | Setting and country | Sample characteristics at randomisation (sample size, gender and age) | Behaviour | Intervention characteristics | Duration | Outcome measurements |
| Andersson,25 | University, Sweden | n=708 I: n=334 C: n=374 M/F >17.5/18 years old | Alcohol consumption | Intervention: total IVR: 4 IVR outbound calls between 13:00 and 19:00 on a Monday and Tuesday. Each voice message involved less than 500 words Comparator: no IVR calls. | Follow-up assessment: 6 weeks Duration of the IVR intervention: 2 weeks | *Alcohol Use Disorders Identification Test, and 16-item Daily Drinking Questionnaire |
| Cizmic et al, 31 | Kaiser Permanente, USA | n=246 I: n=127 C: n=119 ≥18 years old | Medication adherence for osteoporosis (oral bisphosphonate) | Intervention: 1 outbound IVR call of average duration of 145–109 seconds. A letter was sent 7 days after the call to those patients who had not refilled their medications. Comparator: no calls. | Follow-up assessment: 25 days after enrolment and at 6 months for those not meeting the 25 outcome Duration of the IVR intervention: 1 call on the day of enrolment | Medication Possession Ratio |
| Derose et al, 32 | Kaiser Permanente, USA | n=5216 I: n=2606 C: n=2610 M/F >18 years old | Medication adherence for CVDs (statins) | Intervention: outbound call, 1–2 weeks after the prescription date, letters were sent 1 week after the call to those patients who had not refilled their medications. Comparator: no calls or letter. | Follow-up assessment: 25 days from randomisation and initiation of telephone calls Duration of the IVR intervention: approx.1 week | Number of dispensation at three intervals in the following to randomisation year, collected by electronic pharmacy records. |
| Estabrooks 41 | Kaiser Permanente, USA | n=77 I: n=39 C: n=38 M/F >18 years old | Physical activity, diet | Intervention: 1outbound IVR call per week. Each call lasted 5–10 min and targeted physical activity or diet Comparator: no calls. | Follow-up assessment: 3 months Duration of the IVR intervention: 3 months | Physical activity: *Actigraph accelerometer for physical activity (moderate and vigorous) and rapid assessment physical activity scale. Diet: questionnaire for dietary habits (starting the conversation questionnaire) |
| Helzer et al, 6 | Primary care clinics, USA | n=348 I: n=156 C: n=92 M/F >21 years old | Alcohol consumption | Intervention: participants made the calls to the IVR system daily (inbound calls). The duration of each call decreased the first month of calling, reaching a mean of approximately 2 min Comparator: no calls to the IVR system | Follow-up assessment: 6 months Duration of the IVR intervention: 6 months | *The Timeline Follow Back (TLFB) tool |
| King et al, 40 | Community level, USA | n=145 I: n=75 C: n=70 M/F ≥55 years old | Physical activity | Intervention: 15 outbound calls for the duration of the intervention. Comparator: health education classes. | Follow-up assessment at 6 months Duration of the IVR intervention: 12 months | *Stanford 7 day physical activity recall, and Community Healthy Activities Model Program for Seniors questionnaire, and accelerometer for max 7 days for 26% of study randomly selected participants. |
| Migneault et al, 42 | Hospital and community health centres, USA | n=337 I: n=169 C: n=168 M/F ≥35 years old | Physical activity Diet Medication adherence for CVDs (antihypertensive) | Intervention: 1outbound call per week for 32 weeks. From those 12 calls included messages for physical activity; 9 calls included messages for diet consumption and 8 call included messages for medication adherence. Comparator: usual primary care. | Follow-up assessment: 8 months Duration of the IVR intervention: 8 months | Physical activity: *Structured interview 7 Day PAR (subscale minutes per week), and accelerometer for max 7 days (for 48 randomly selected participants). Diet: Picture-sort Food Frequency Questionnaire Medication adherence: Morisky Medication Adherence Scale |
| Rose et al, 39 | Community, USA | n=158 I: n=81 C: n=77 M/F ≥18 years old | Alcohol consumption | Intervention: daily outbound calls, with subsequent inbound calls. Comparator: usual care. | Follow-up assessment: 4 months Duration of the IVR intervention: 4 months | TLFB tool (drinks per week). |
| Rose et al, 43 | Primary care, USA | n=1855 I: 938 C: 917 M/F ≥18 years old | Alcohol consumption | Intervention: single IVR call Comparator: usual care. | Follow-up assessment: end of intervention. Duration of the IVR intervention: Uncl | TLFB tool (drinks per week). |
| Sherrard et al, 38 | University of Ottawa Heart Institute (UOHI), Canada | n=331 M/F >18 years old | Medication adherence for CVDs (discharged postsurgery medications) | Intervention: 11 outbound IVR call in predetermined time for the duration of the intervention Comparator: usual medical care. | Follow-up assessment: 6 months Duration of the IVR intervention: 6 months | Self-reported (single item: remained or not on medication) |
| Sherrard et al, 35 | Hospital in Ontario, Canada | n=1608 I: n=803 C: n=805 M/F >18 years old | Medication adherence for coronary syndrome | Intervention: 5 outbound IVR calls in predetermined time between 10:00 and 12:00, 15:00–17:00 or 18:00–20:00, for the duration of the intervention. Comparator: usual medical care. | Follow-up assessment: 12 months Duration of the intervention: 12 months | Self-reported (single item: remained or not on medication). |
| Shet et al, 34 | Two ambulatory clinics and one private HIV clinic, India | n=631 I: n=315 C: n=316 M/F 18–60 years old | Medication adherence for HIV (ART) | Intervention: 1outbound and interactive IVR call per week in predetermined time and weekly non-interactive calls 4 days after the IVR call Comparator: usual medical care. | Follow-up assessment: 24 months Duration of the intervention: Uncl | Pill count measured by researcher. |
| Stacy et al, 36 | Large health benefits company, USA | n=578 M/F ≥21 years old | Medication adherence for CVDs (statins) | Intervention: 3outbound IVR calls Comparator: 1 IVR call with general health advice. | Follow-up assessment: 6 months Duration of the intervention: Uncl | Point prevalence adherence collected by electronic medical records. |
| Vollmer et al, 37 | Kaiser Permanente, USA | n=8517 M/F 18–98 years old | Medication adherence for asthma (ICS) | Intervention: each participant received 1 of the 3 outbound IVR call types, each call lasted 2–3 minutes 1. Refill reminder: last ICS dispensing >1 month and <30 days supply 2. Tardy refill: >1 month past projected refill date 3. Initiator/restart: starting ICS for first time or lapsed users Comparator: usual care. | Follow-up assessment: 18 months Duration of the IVR intervention: Uncl | Modification of the Medication Possession Ratio, collected by electronic medical records. |
| Vollmer et al, 33 | Kaiser Permanente, USA | n=14 502 M/F ≥40 years old | Medication adherence for CVD (statins) | IVR group: outbound IVR calls when due or overdue for refill medications. Comparator: usual care | Follow-up assessment: 12 months Duration of the IVR intervention: Uncl | Modification of the Proportion of Days Covered collected by electronic medical records. |
*Outcome measures included in the meta-analysis.
ART, antiretroviral treatment; C, comparator group; CVDs, cardiovascular diseases; F, female; I, Intervention group; ICS, inhaled corticosteroids; M, male; Uncl, unclear information.