Table 2 Recommended content of statistical analysis plans for observational studies
From: DEBATE-statistical analysis plans for observational studies
Section/Item | Index | Description for observational studies |
|---|---|---|
Section 1: Administrative information | ||
Title and study registration | 1a | Descriptive title that matches the protocol, with SAP either as a forerunner or subtitle, and study acronym |
1b | Study registration number | |
SAP version | 2 | SAP version number with dates |
Protocol version | 3 | Reference to version of protocol being used |
SAP revisions | 4a | SAP revision history |
4b | Justification for each SAP revision | |
4c | Timing of SAP revisions in relation to planned repetitive analyses | |
Roles and responsibility | 5 | Names, affiliations, and roles of SAP contributors |
Signatures of: | 6a | Person writing the SAP |
6b | Senior statistician responsible | |
6c | Chief investigator/clinical lead | |
Section 2: Introduction | ||
Background and rationale | 7 | Synopsis of study background and rationale including a brief description of research question and brief justification for undertaking the study |
Objectives | 8 | Description of specific objectives and hypotheses, including secondary objectives |
Section 3: Study methods | ||
Study design | 9 | Brief description of study design including type of study (e.g. case-control, cross-sectional or cohort study) |
Power considerations | 10 | In case of an unspecified sample size, provide power calculations for (at least) the primary analysis or present a detectable difference with a specified power* |
Framework | 11 | Superiority, equivalence, or noninferiority hypothesis testing framework, including which comparisons will be presented on this basis |
Statistical interim analyses and stopping guidance | 12a | Information on repetitive analyses specifying what repetitive analyses will be carried out and listing of time points |
12b | Any planned adjustment of the significance level due to repetitive analyses | |
12c | Details of guidelines for stopping the study early | |
Timing of final analysis | 13 | Timing of final analysis, e.g., all outcomes analysed collectively or timing stratified by planned length of follow-up* |
Timing of outcome assessments | 14 | Time points at which the outcomes are measured including visit “windows” |
Section 4: Statistical principles | ||
Confidence intervals and P-values | 15 | Level of statistical significance* |
16 | Description and rationale for any adjustment for multiplicity and, if so, detailing how the type 1 error is to be controlled* | |
17 | Confidence interval to be reported | |
Adherence and protocol deviations | 18a | Definition of protocol deviations for the trial |
18b | Description of which protocol deviations will be summarized | |
Analysis populations | 19 | Definition of analysis populations, e.g., intention to treat, per protocol, complete case, safety |
Section 5: Study Population | ||
Screening data | 20 | Reporting of screening data (if collected) to describe representativeness of study sample |
Eligibility | 21 | Summary of eligibility criteria |
Recruitment | 22 | Information to be included in the STROBE flow diagram* |
Withdrawal/follow-up | 23a | Level of withdrawal, e.g., dropouts after inclusion or refusal to be contacted for additional information |
23b | Timing of withdrawal/lost to follow-up data | |
23c | Reasons and details of how withdrawal/lost to follow-up data will be presented | |
Baseline patient characteristics | 24a | List of baseline characteristics to be summarized |
24b | Details of how baseline characteristics will be descriptively summarized | |
Potential confounding covariates | 25 | A description of potential confounding covariates and how these will be dealt with* |
Section 6: Analysis | ||
Outcome definitions | List and describe each primary and secondary outcome including details of: | |
26a | Specification of outcomes and timings. If applicable include the order of importance of primary or key secondary end points (e.g., order in which they will be tested) | |
26b | Specific measurement and units (e.g., glucose control, HbA1c [mmol/mol or %]) | |
26c | Any calculation or transformation used to derive the outcome (e.g., change from baseline, QoL score, time to event, logarithm, etc) | |
Analysis methods | 27a | What analysis method will be used and how the treatment effects will be presented* |
27b | Any adjustment for covariates | |
27c | Methods used for assumptions to be checked for statistical methods | |
27d | Details of alternative methods to be used if distributional assumptions do not hold, e.g., normality, proportional hazards, etc | |
27e | Any planned sensitivity analyses for each outcome where applicable* | |
27f | Any planned subgroup analyses for each outcome including how subgroups are defined* | |
Missing data | 28 | Reporting and assumptions/statistical methods to handle missing data (e.g., multiple imputation)* |
Additional analyses | 29 | Details of any additional statistical analyses required, e.g. complier-average causal effect analysis |
Harms | 30 | Only applies when intervention effects are studied. Sufficient detail on summarizing safety data, e.g. information on severity, expectedness, and associations; details of how adverse events are scored; how adverse event data will be analysed and the follow-up time. |
Statistical software | 31 | Details of statistical packages to be used to carry out analysis |
References | 32a | References to be provided for nonstandard statistical methods |
32b | Reference to Data Management Plan | |
32c | Reference to the Study Master File and Statistical Master File | |
32d | Reference to other standard operation procedures to be adhered to | |