What is it? Why is it important?
Database Lock (DL) is an action taken by the SP-INV upon study completion to prevent unauthorized or unintentional changes to the data after final data entry completion.
The DL is performed once:
- All study data are entered into the study database
- Open issues during data review, (e.g. data queries) are answered by the study site and considered resolved by the SP-INV
- Site-INV and/or SP-INV confirm that data is complete and correct
Final DL can be faster if interim locks have already been performed during study conduct.
In addition, intermittent database locks allow the SP-INV to evaluate and analyse the data in the framework of an interim analysis in order to decide whether:
- It is worthwhile to continue the study, (e.g. intervention shows no expected effect)
- The study must be stopped due to ethical concerns, (e.g. treatment group performs significantly better than placebo or control group)
- The study must be stopped due to serious safety concerns in the treatment group compared to control or placebo group
Once the database is locked the data can be exported for statistical analysis.
What do I need to do?
- Set-up well-defined processes for database lock
- In a multicentre study, study sites might close their study at different time points. This must be accordingly managed by SP-INV who will perform a “global” lock once all sites meet closing criteria
- Document the exact timing when the database was locked, in order to prove that:
- Statistical analysis took place after the database was locked
- The blind of your randomised blinded study was broken after database lock
Database lock should follow procedures as defined in the data management plan.
For more information refer to Data Handling in this Study Guide.
In order to facilitate database lock, plan ahead and ensure that:
- Data entries are performed on an ongoing basis, while data is still “fresh”. Retrospective entry of large volumes of data carries increased quality risks
- External data providers (e.g. laboratories) are informed regarding upcoming database lock in order to integrate their data into the main study database
- Adequate time for data review and resolution of data queries is given.
- Site-INV can sign off any complete and correct data on an ongoing basis (interim locks), so as not to postpone this task to the very end.
Where can I get help?
Your local CTU↧ can support you with experienced staff regarding this topic
Basel, Clinical Trials Unit, CTU, dkf.unibas.ch
Bellinzona, Clinical Trials Unit, CTU-EOC, www.ctueoc.ch
Bern, Clinical Trials Unit, CTU, www.ctu.unibe.ch
Geneva, Clinical Research Center, CRC, crc.hug.ch
Lausanne, Clinical Research Center, CRC, www.chuv.ch
St. Gallen, Clinical Trials Unit, CTU, www.kssg.ch
Zürich, Clinical Trials Center, CTC, www.ctc.usz.ch
ICH GCP E6(R2) – see in particular guideline
- 5.5. Trial management, data handling, and record keeping
ISO 14155:2020 Medical devices - see in particular sections (access liable to cost)
- 8.6 Documentation retention