Table 2.
Characteristics of included communication trials
| Trial | Number randomised | Disease/condition | Participants | Setting | Intervention(s) | Control | Outcome retention trial | Time point used in analysis |
|---|---|---|---|---|---|---|---|---|
| Enhanced letter vs standard letter | ||||||||
| Renfroe 2002 (c) | 664 | Treatment of ventricular tachycardia (VT) ventricular fibrillation (VF) | Adults cardioverted from VT or resuscitated from VF | US hospital | Cover letter signed by physician | Cover letter signed by coordinator | Postal questionnaire response | Overall response |
| Marson 2007 | 1815 | Treatment of epilepsy | Adults with epilepsy | UK hospital outpatient departments | Letter explaining the approximate time needed to complete the questionnaire | Standard letter | Postal questionnaire response | Overall response |
| Total design postal method for postal questionnaires vs customary method | ||||||||
| Sutherland 1996 | 226 | Prevention of breast cancer | Women with 50% breast volume dysplasia | Canada hospital clinic | Total design method for postal follow-up | Customary method for postal follow-up | Postal questionnaire response | Response at day 70 |
| Priority vs regular post | ||||||||
| Renfroe 2002 (b) | 664 | Treatment of ventricular tachycardia (VT) ventricular fibrillation (VF) | Adults cardioverted from VT or resuscitated from VF | US hospital | Overnight questionnaire delivery | Standard questionnaire delivery | Postal questionnaire response | Overall response number of questionnaires returned |
| Sharp 2006 (e) | 233 | Screening of cervical cancer | Women with low-grade abnormal cervical smear | UK primary care | First class outward post | Second class outward post | Postal questionnaire response | Overall response |
| Sharp 2006 (f) | 231 | Screening of cervical cancer | Women with low-grade abnormal cervical smear | UK primary care | First class outward post | Second class outward post | Postal questionnaire response | Overall response |
| Sharp 2006 (g) | 240 | Screening of cervical cancer | Women with low-grade abnormal cervical smear | UK primary care | Stamped reply envelope | Business reply envelope | Postal questionnaire response | Overall response |
| Sharp 2006 (h) | 223 | Screening of cervical cancer | Women with low-grade abnormal cervical smear | UK primary care | Stamped reply envelope | Business reply envelope | Postal questionnaire response | Overall response |
| Kenton 2007 (c) | 149 | Screening of postnatal depression | Women postpartum at high risk of postnatal depression | Canada community | Priority outward mail | Regular outward mail | Postal questionnaire response | Overall response |
| Kenton 2007 (d) | 148 | Screening of postnatal depression | Women postpartum at high risk of postnatal depression | Canada community | Priority outward mail | Regular outward mail | Postal questionnaire response | Overall response |
| Additional reminder vs usual follow-up procedures | ||||||||
| Ashby 2011 | 148 | Prevention of migraine | Adults with a history of two migraine attacks | UK community | Electronic reminder (email and/or SMS text) | No electronic reminder | Postal questionnaire response | Response at 40 days |
| Maclennan unpublished | 753 | Prevention of fracture | Adults with a history of osteoporotic fracture | UK hospital | Telephone reminder (before receiving first reminder) | No telephone reminder | Postal questionnaire response | Overall response response rate |
| Nakash unpublished | 298 | Treatment of ankle injury | Adults with acute severe ankle sprain | UK accident and emergency departments | Trial calendar with questionnaire due dates | No calendar | Postal questionnaire response at 4, 12 weeks, and 9 months | Response at 4 weeks |
| Severi 2011 (1) | 1950 | Treatment of smoking dependence | Adult smokers willing to quit in Txt2stop | UK community | Text message and fridge magnet emphasising social benefits of study participation | Text message 3 days after questionnaire sent reminding questionnaire is due | Postal questionnaire response | Response at 30 weeks from randomisation |
| Severi 2011 (2) | 127 | Treatment of smoking dependence | Adult smokers willing to quit in Txt2stop | UK community | Telephone reminder from principal investigator that participant is 6 weeks overdue returning their specimen | Standard text and no phone call from principle investigator | Return of cotinine samples | Completed cotinine sample follow-up for Txt2stop at end of May 2009 |
| Man 2011 | 125 | Treatment of back pain | Adults with back pain | UK primary care | SMS text reminder message as follow-up questionnaire sent out | No SMS text message | Postal questionnaire response | Overall response rate |
| Monthly reminder of upcoming assessment to site vs usual reminders | ||||||||
| Land 2007 | 429 | Treatment of breast cancer | Women with ductal carcinoma in situ | Hospital sites USA, Canada, Puerto Rico | Prospective monthly reminder of upcoming assessments to sites | No extra reminders to sites | Postal questionnaire response | Overall response rate |
| Early vs late administartion of questionnaire | ||||||||
| Renfroe 2002 (d) | 664 | Treatment of ventricular tachycardia (VT) ventricular fibrillation (VF) | Adults cardioverted from VT or resuscitated from VF | US hospital | Questionnaire sent 2–3 weeks after last AVID follow-up visit | Questionnaire sent 1-4 months after last AVID follow-up visit | Postal questionnaire response | Overall response number of questionnaires returned |
| Recorded delivery vs telephone reminder | ||||||||
| Tai 1997 | 192 | Clinical management of asthma and diabetes | Adults with asthma or diabetes | UK primary care | Recorded delivery reminder | Telephone reminder | Postal questionnaire response | Overall response number of questionnaires returned |
| Telephone interview vs questionnaire and monetary incentive | ||||||||
| Couper 2007 | 700 | Weight management | Adults with BMI >25 | US community web based | Telephone interview by trained interviewer | Postal questionnaires with $5 bill | Post and telephone questionnaire response | Response at 6 months |