Table 5.
Statistical methods addressing nonadherence to treatment protocol
| Number (%b) | Definition of analysis set | Number | |
|---|---|---|---|
|
Reported a statistical method addressing nonadherence to treatment protocola |
51 (52) |
|
|
| Variant of PP |
|
||
| |
Primary PP analysis described as ‘PP’ |
18 |
|
| |
|
Included only those participants who received full randomised intervention |
8 |
| |
|
2 |
|
| |
|
Minimum degree of adherence required |
5c |
| |
|
Included only those taking treatment at particular time during trial |
1 |
| |
|
Excluded participants if they started disallowed medication |
1 |
| |
|
1 |
|
| |
Primary PP analysis described as ‘ITT’ or ‘modified ITT’ analysis |
23 |
|
| |
|
Included only those participants who received full randomised intervention |
1 |
| |
|
Included only those participants who received at least one dose of randomised intervention |
16 |
| |
|
Included only those participants who received the single treatment |
3 |
| |
|
Excluded participants if they deviated from treatment protocol |
3 |
| |
Sensitivity analysis |
12 |
|
| |
|
Included only those participants who received full randomised intervention |
4 |
| |
|
Excluded participants if they received disallowed treatments |
2 |
| |
|
Minimum degree of adherence required |
2d |
| |
|
Censored participants at the point of deviation from treatment protocol |
4e |
| |
Inverse probability of censoring weighted method |
1f |
|
| |
Subgroup analysis |
2g |
|
| |
Unlabelled analysis |
1h |
|
| As treated analysis |
|
3 |
|
| Discontinuation of treatment analysed as treatment failure |
|
3 |
|
| Time to treatment discontinuation included as trial outcome |
|
4 |
|
| Did not report a statistical method to address nonadherence to treatment protocol | 47 (48) | ||
aNine trials carried out two methods of analysis, two trials carried out three methods and one trial carried out four methods. bNumber of trials reporting some form of nonadherence (98) is used as denominator for %. cAdherence thresholds used were 60%, 2/3, 75%, 80% and 90%. dAdherence thresholds used were 2/3 and 5/6. eCensoring times: time of starting disallowed intervention, when participants reported taking less than 2/3 of their medication in the past year, when received treatment out of trial, or censored following six-month lag after receiving less than 80% of drug. fCensored when received <80% of drug, weighted by the inverse probability of each participant’s estimated adherence probability. gAnalysis split into two groups (according to whether participants had taken more or less than 50% of the prescribed medication) in one trial and into three groups (according to the proportion (>90%, 75-90% or <75%) of their time at risk that they were supplied with drug) in other trial. hIncluded if received at least one dose of treatment. ITT: intention to treat; PP: per protocol.