Table 4 Total cost and cost per participant for each retention strategy for all trials
From: How much is the lack of retention evidence costing trial teams in Ireland and the UK?
Strategy | Cost | CINNAMON trial [16] | |||
|---|---|---|---|---|---|
Ireland (Hypothetical trial) | UK (Hypothetical trial) | MAMI trial [14] | MOON trial [15] | ||
Strategy 1: Newsletters (posted) | €2040 (£1754.40) | €1657.67 (£1425.60) | €895.68 (£770.29) | €755.17 (£649.45) | €1931.83 (£1661.33) ($2289.44) |
Assumptions | 2 newsletters per year; 500 participants; 1-year trial period. | 2 newsletters per year; 500 participants; 1-year trial period. | 2 newsletters per year; 60 participants; 2-year trial perioda. | 2 newsletters per year; 154 participants; 1-year trial period. | 2 newsletters per year; 428 participants; 2-year trial period. |
Effect estimateb | “The evidence is very uncertain about the effect on retention of including a newsletter compared to no newsletter: RD = − 0% (95% CI − 4% to 3%); GRADE: very low” | ||||
Cost per participant retained | Current evidence suggests no retention benefit, unable to calculate cost per participant retained due to lack of evidence | ||||
Strategy 1: Newsletters (emailed) | €791.78 (£680.93) | €639.45 (£549.93) | €919.88 (£791.10) | €546.59 (£470.07) | €1094.17 (£940.96) ($1296.72) |
Assumptions | 2 newsletters electronically sent per year; 500 participants; 1 year trial period | 2 newsletters electronically sent per year; 500 participants; 1 year trial period | 2 newsletters electronically sent per year; 60 participants; 2-year trial period | 2 newsletters electronically sent per year; 154 participants; 1 year trial period | 2 newsletters electronically sent per year; 428 participants; 2-year trial period |
Effect estimate | “The evidence is very uncertain about the effect on retention of including a newsletter compared to no newsletter: RD = − 0% (95% CI − 4% to 3%); GRADE: very low” | ||||
Cost per participant retained | Current evidence suggests no retention benefit, unable to calculate cost per participant retained due to lack of evidence | ||||
Strategy 2: A timeline of participant visits for sites (site reminder)c | €79.18 (£68.09) | €111.95 (£96.28) | €101.34 (£87.15) | €111.95 (£96.28) | €112.23 (£96.52) ($133.01) |
Assumptions | Data Manager develops reminder schedule software, electronically emails the software to the sites (10 sites). Carried out once. This software is used to notify staff of upcoming participant trial visits | Data Manager develops reminder schedule software, electronically emails the software to the sites (10 sites). Carried out once. This software is used to notify staff of upcoming participant trial visits | Data Manager develops reminder schedule software, electronically emails the software to the sites (1 site). Carried out once. This software is used to notify staff of upcoming participant trial visits | Data Manager develops reminder schedule software, electronically emails the software to the sites (1 site). Carried out once. This software is used to notify staff of upcoming participant trial visits | Data Manager develops reminder schedule software, electronically emails the software to the sites (5 sites). Carried out once. This software is used to notify staff of upcoming participant trial visits |
Effect estimate | No evidence provided in the systematic review | ||||
Cost per participant retained | Unable to calculate cost per participant retained due to lack of evidence | ||||
A timeline of participant visits for sites (participant reminder)c | €9232.18 (£7939.68) | €6103.57 (£5249.08) | €304.74 (£262.08) | €1957.37 (£1683.34) | €14803.70 (£12730.79) ($17544.05) |
Assumptions | Research nurse contacts 500 participants – 5 min per call-carried out once for each visit (3 visits) Failed contact attempts – research nurse contacts 500 participants - 2 failed contact attempts (1 min each) – carried out once for each visit (3 visits) | Trial Manager contacts 500 participants – 5 min per call-carried out once for each visit (3 visits) Failed contact attempts – trial manager contacts 500 participants - 2 failed contact attempts (1 min each) – carried out once for each visit (3 visits) | Research nurse contacts 60 participants – 5 min per call-carried out once (1 trial visit) Failed contact attempts – research nurse contacts 60 participants - 2 failed contact attempts (1 min each) – carried out once (1 trial visit) | Trial Manager contacts 154 participants – 5 min per call-carried out once for each visit (3 visits) Failed contact attempts – trial manager contacts 154 participants - 2 failed contact attempts (1 min each) – carried out once for each visit (3 visits) | Research nurse contacts 428 participants – 5 min per call-carried out once for each visit (9 trial visits) Failed contact attempts – research nurse contacts 428 participants - 2 failed contact attempts (1 min each) – carried out once for each visit (9 trial visit) |
Effect estimate | No evidence provided in the systematic review | ||||
Cost per participant retained | Unable to calculate cost per participant retained due to lack of evidence | ||||
Strategy 3: Inclusion of pre-paid envelopes (questionnaire) | €1690.00 (£1453.40) | €1346.56 (£1158.04) | €170.98 (£147.04) | €832.79 (£716.20) | €667.40 (£573.94) ($790.94) |
Assumptions | 1 questionnaire to all 500 participants; cost of stamp to send out and to return; 1 reminder to 30% of participants (150); cost of stamp to send out and to return; | 1 questionnaire to all 500 participants; cost of stamp to send out and to return; 1 reminder to 30% of participants (150); cost of stamp to send out and to return | 1 questionnaire to all 60 participants; cost of stamp to send out and to return; 1 reminder to 30% of participants (18); cost of stamp to send out and to return | 2 questionnaires to all 154 participants; cost of stamp to send out and to return; 1 reminder for each questionnaire to 30% of participants (47); cost of stamp to send out and to return | 1 questionnaire to all 428 participants; cost of stamp to send out and to return; 1 reminder to 30% of participants (129); cost of stamp to send out and to return |
Effect estimate | “Various strategies compared to usual practice for return postage, such as free post versus second class stamp; high priority mail stamp versus usual postage; and personal form may increase retention slightly: RD = 4% (95% CI − 0% to 9%); GRADE: low” d | ||||
Additional participants retained | 20 | 20 | 3 | 7 | 18 |
Cost per participant retained | €84.50 (£72.67) | €67.33 (£57.90) | €57 (£s49.02) | €118.97 (£102.31) | €37.08 (£31.88) ($43.94) |
Strategy 4: Telephone reminders | |||||
Telephone reminders for trial visits | €9153 (£7871.59) | €5991.62 (£5152.80) | €203.40 (£174.92) | €1845.42 (£1587.06) | €14691.47 (£12634.27) ($17411.04) |
Assumptions | Research nurse contacts 500 participants– 5 min per call-carried out once for each visit (3 visits) Failed contact attempts – research nurse contacts 500 participants - 2 failed contact attempts (1 min each) – carried out for each visit (3 visits) | Trial Manager contacts 500 participants– 5 min per call-carried out once for each visit (3 visits) Failed contact attempts – trial manager contacts 500 participants - 2 failed contact attempts (1 min each) – carried out for each visit (3 visits) | Research nurse contacts 60 participants– 5 min per call-carried out once (1 trial visit) Failed contact attempts – research nurse contacts 60 participants - 2 failed contact attempts (1 min each) – carried out once (1 trial visit) | Trial Manager contacts 154 participants– 5 min per call-carried out once for each visit (3 visits) Failed contact attempts – trial manager contacts 154 participants - 2 failed contact attempts (1 min each) – carried out for each visit (3 visits) | Research nurse contacts 428 participants– 5 min per call-carried out once for each visit (9 trial visits) Failed contact attempts – research nurse contacts 428 participants - 2 failed contact attempts (1 min each) – carried out once for each visit (9 trial visit) |
Effect estimate | “Telephone reminders compared to usual follow-up may result in little or no difference to retention (smoking cessation (14)): RD = − 1% (95% CI -18% to 15%); GRADE low (− 2 levels: imprecision-single study, n = 127; wide CI crossing RD = 0)” e | ||||
Cost per participant retained | With a risk difference of negative 1 there are no participants retained with this strategy so cost per participant retained cannot be calculated | ||||
Telephone reminders for questionnaire response | €423.75 (£364.43) | €568.62 (£489.01) | €34.58 (£29.74) | €356.33 (£306.44) | €246.00 (£211.56) ($291.54) |
Assumptions | Research assistant contacts 30% of participants (150) – 5 min per call – carried out once Failed contact attempts – research assistant contacts 150 participants– 2 failed attempts - 1 min per attempt –carried out once | Research assistant contacts 30% of participants (150) – 5 min per call – carried out once Failed contact attempts – research assistant contacts 150 participants– 2 failed attempts - 1 min per attempt –carried out once | Research assistant contacts 30% of participants (18) – 5 min per call – carried out once Failed contact attempts – research assistant contacts 18 participants– 2 failed attempts - 1 min per attempt –carried out once | Research assistant contacts 30% of participants (47)– 5 min per call – carried out twice Failed contact attempts – research assistant contacts 47 participants– 2 failed attempts - 1 min per attempt –carried out twice | Research assistant contacts 30% of participants (129) – 5 min per call – carried out once Failed contact attempts – research assistant contacts 129 participants– 2 failed attempts - 1 min per attempt –carried out once |
Effect estimate | “Telephone reminders compared to usual follow-up may result in little or no difference to retention (smoking cessation [11]): RD = − 1% (95% CI −18% to 15%); GRADE low (− 2 levels: imprecision-single study, n = 127; wide CI crossing RD = 0)”e | ||||
Cost per participant retained | With a risk difference of negative 1 there are no participants retained with this strategy so cost per participant retained cannot be calculated | ||||
Telephone reminders for at home data collection | €244.08 (£209.91) | ||||
Assumptions | Research nurse contacts 30% of participants [18] – 5 min per call - 1 reminder for each at home data collection (4 in total) | ||||
Effect estimate | “Telephone reminders compared to usual follow-up may result in little or no difference to retention (smoking cessation [11]): RD = − 1% (95% CI − 18% to 15%); GRADE low (− 2 levels: imprecision-single study, n = 127; wide CI crossing RD = 0)”e | ||||
Cost per participant retained | With a risk difference of negative 1 there are no participants retained with this strategy so cost per participant retained cannot be calculated | ||||
Strategy 5: Data collection scheduled with routine care | €20250 (£17415.02) | €15697.67 (£13500) | €900 (£774.00) | €4834.88 (£4158) | €32503.25 (£27951.92) ($38520) |
Assumptions | Carried out by a research nurse during a routine care visit – 15 min – carried out 3 times for each participant (once for each trial visit) | Carried out by a research nurse during a routine care visit – 15 min – carried out 3 times for each participant (once for each trial visit) | Carried out by a research nurse during a routine care visit – 15 min – carried out twice for each participant (outpatient clinic data collection and data collection at birth) | Carried out by a research nurse during a routine care visit – 15 min – carried out 3 times for each participant - once for each trial visit (3 trial visits) | Carried out by a research nurse during a routine care visit – 15 min – carried out 9 times for each participant - once for each trial visit (9 trial visits) |
Effect estimate | No evidence provided in the systematic review | ||||
Cost per participant retained | Unable to calculate cost per participant retained due to lack of evidence | ||||
Strategy 6: Site initiation training on missing data | €7000 (£6020.00) | €7376.74 (£6344) | €400 (£344.00) | €388.83 (£334.40) | €2953.31 (£2539.76) ($3500) |
Assumptions | Prep, site training and report per site @€400 per day plus travel and overnight costs. Carried out once for each site (10 sites) | Prep, site training and report by Trial manager (11 h of work) – plus travel and overnight costs. Carried out once for each site (10 sites) | Prep, site training and report per site @€400 per day. Carried out once (1 site) | Prep, site training and report by Trial Manager (11 h of work) Carried out once (1 site) | Prep, site training and report per site @€400 per day plus travel and overnight costs. Carried out once for each site (5 sites) |
Effect estimate | No evidence provided in the systematic review | ||||
Cost per participant retained | Unable to calculate cost per participant retained due to lack of evidence | ||||
Strategy 7: Investigator meetings face to face | €14000 (£12040.01) | €14753.48 (£12688) | €1600 (£1376) | €777.67 (£668.80) | €11813.22 (£10159.06) ($14000) |
Assumptions | Prep, meeting, and report per site @€400 per day plus travel and overnight costs. Carried out twice per site over 1 year trial period (10 sites) | Prep, meeting, and report by Trial manager (11 h of work) – plus travel and overnight costs. Carried out twice per site over 1 year trial period (10 sites) | Prep, meeting, and report per site @€400 per day Carried out 4 times for each site over 2-year trial period (1 site) | Prep, meeting, and report by Trial manager (11 h of work). Carried out twice per site over 1 year trial period (1 site) | Prep, meeting, and report per site @€400 per day plus travel and overnight costs. Carried out 4 times for each site over 2-year trial period (5 sites) |
Effect estimate | No evidence provided in the systematic review | ||||
Cost per participant retained | Unable to calculate cost per participant retained due to lack of evidence | ||||
Strategy 8: Routine site visits by CTU staff | €14000 (£12040.01) | €14753.48 (£12688) | €1600 (£1376) | €777.67 (£668.80) | €11813.22 (£10159.06) ($14000) |
Assumptions | Prep, site visit and report per site @€400 per day plus travel and overnight costs. Carried out twice per site over 1 year trial period (10 sites) | Prep, site visit and report by Trial manager (11 h of work) – plus travel and overnight costs. Carried out twice per site over 1 year trial period (10 sites) | Prep, site visit and report per site @€400 per day Carried out 4 times per site over 2-year trial period (1 site) | Prep, site visit and report by Trial manager (11 h of work). Carried out twice per site over 1 year trial period (1 site) | Prep, site visit and report per site @€400 per day plus travel and overnight costs Carried out 4 times per site over 2-year trial period (5 sites) |
Effect estimate | No evidence provided in the systematic review | ||||
Cost per participant retained | Unable to calculate cost per participant retained due to lack of evidence | ||||
Strategy 9: Targeted recruitment of sites/GPsf | €1620 (£1393.20) | €1060.46 (£912) | €30 (£25.80) | €35.35 (£30.40) | €506.28 (£435.39) ($600) |
Assumptions | Research nurse carries out site selection and investigation (1 h work per site) – 30 sites are targeted | Trial manager carries out site selection and investigation (1 h work per site) – 30 sites are targeted | Research nurse carries out site selection and investigation (1 h work per site) –single centre so only 1 site targeted | Trial manager carries out site selection and investigation (1 h work per site) – single centre so only 1 site targeted | Research nurse carries out site selection and investigation (1 h work per site) – 15 sites are targeted |
Effect estimate | No evidence provided in the systematic review | ||||
Cost per participant retained | Unable to calculate cost per participant retained due to lack of evidence | ||||
Strategy 10: Flexibility in appointments | €4050 (£3483.00) | €3139.53 (£2700) | €270 (£232.20) | €1004.65 (£864) | €2177.01 (£1872.17) ($2580) |
Assumptions | Research nurse carries out out-of-hours visits for 10% of participants (50) – 1.5-h visit | Research nurse carries out out-of-hours visits for 10% of participants (50) – 1.5-h visit | Research nurse carries out out-of-hours visits for 10% of participants (6) – 1.5-h visit | Research nurse carries out out-of-hours visits for 10% of participants (16) – 1.5-h visit | Research nurse carries out out-of-hours visits for 10% of participants (43) – 1.5-h visit |
Effect estimate | No evidence provided in the systematic review | ||||
Cost per participant retained | Unable to calculate cost per participant retained due to lack of evidence | ||||