Pain is measured every day, not every visit. Capture runs daily pain diaries on participants' phones, tracks compliance before it becomes missing data, and keeps rescue medication, function and global impression on the same schedule.
Free sandbox · No credit card · 21 CFR Part 11 aligned
Evening pain diary
Day 18 · Treatment week 2
Average pain over the last 24 hours
0 no pain · 10 worst pain imaginable
Did you take rescue medication today?
How many tablets?
What matters in pain trials
The endpoint
A weekly average built from seven daily ratings is a robust measure. The same average built from two ratings is not, and a participant who stops completing the diary mid-trial creates missing data exactly where the treatment effect is measured. That is why pain trials usually set a minimum number of completed diary days per week for the weekly average to count.
Paper diaries made this worse: entries completed in the car park before a visit ("parking lot compliance") look complete but are not daily. Electronic diaries with completion windows solve that by accepting entries only in the window they refer to. Capture's windows can be soft, hard, warning-only or auto-close, and reminders go out when an entry is due, the next day and before the window closes.
Most protocols require a minimum average baseline pain and a minimum number of completed baseline diary days before randomisation. Running the baseline diary in the same system as the rest of the study means those rules are checked on the same data that feeds the endpoint.
Alongside mean change, pain trials commonly report the proportion of participants with at least 30% and at least 50% reductions in pain. Those analyses need a complete baseline and complete weekly averages, which is another reason compliance matters.
Participants
58
≥ 5 of 7 days
52
At risk
6
3 participants missed 3 or more days
Outcome domains
| Domain | Typical measure | How it runs in Capture |
|---|---|---|
| Pain | Daily NRS or VAS, weekly average | Recurring ePRO diary with completion window |
| Physical functioning | Disease-specific function scale or pain interference items | Visit-based ePRO or site form |
| Emotional functioning | Depression and anxiety questionnaires | Visit-based ePRO, e.g. PHQ-9 and GAD-7 |
| Global improvement | Patient global impression of change (7-point) | Single-choice ePRO at follow-up visits |
| Symptoms and adverse events | AE log, specific symptom questions | AE log form with minimum dataset |
| Disposition | Completion, withdrawal reasons, rescue use | Subject status and structured reasons |
Rescue medication
If participants take rescue analgesics, pain on those days reflects the rescue drug as well as the study treatment. Asking about rescue use in the same evening diary as pain ratings gives the analysis what it needs to handle it according to the estimand, without relying on recall at the next visit.
When due
18:00
Your evening diary is open
Next day
18:00
Reminder: your diary is still open
Final notice
21:30
Last chance before the window closes
Quiet hours
22:00 to 08:00 in the participant's time zone
Stops
As soon as the task is completed
Indications
Osteoarthritis, low back pain, neuropathic pain and fibromyalgia trials each add their own function or impact measures to the daily diary. Build each as its own form, place it at the visits the protocol specifies, and record licence details where the instrument requires one.
| Assessment | Scr | Run-in | W1 | W2 | W4 | W8 | W12 |
|---|---|---|---|---|---|---|---|
| Daily pain NRS | D | D | D | D | D | D | |
| Rescue medication | D | D | D | D | D | D | |
| Disability questionnaire | |||||||
| PGIC | |||||||
| PHQ-9 |
D = daily evening diary
Build a daily diary with rescue medication in the free sandbox.
Design
Analgesic trials are notorious for large placebo responses. Some of that is expectation and regression to the mean, which design must address. But some is measurement noise that better data practices can reduce: participants who rate pain inconsistently, baseline scores inflated to meet entry criteria, and missed diary days filled in from memory.
Three practices help. Train participants on the rating scale at screening, so "5" means the same thing throughout the study. Use the baseline diary, not a single clinic rating, to assess eligibility, which filters out people whose pain varies too much to show an effect. And enforce completion windows so every score is recorded on the day it describes. All three rely on the diary being in the same system as the rest of the study, with its compliance visible to the team.
Trials involving opioids or other drugs with abuse potential often add assessments of misuse, withdrawal and drug liking, and tighter drug accountability. Those are site forms and logs like any others; the IMP inventory and accountability features keep dispensing and returns reconciled.
Study build
NRS or VAS, anchors and recall period identical in every entry.
Minimum average pain and minimum completed diary days before randomisation.
Minimum days per week for a valid average, pre-specified.
Yes or no with doses, same entry as the rating.
Function, emotional functioning, global impression, AEs and disposition.
Weekly review of at-risk participants on the dashboard.
Change from baseline in average daily pain intensity, usually from a daily 0 to 10 numeric rating scale averaged over a week.
Completion windows ensure entries are made on the day they refer to, reminders improve compliance, and sites can see missed days in real time.
On the same daily diary as the pain rating, with whether rescue was taken and how much.
Pain, physical functioning, emotional functioning, participant ratings of improvement, symptoms and adverse events, and participant disposition.
No. Diaries open in the phone browser from a secure link.
Yes. The free sandbox includes ePRO diaries and every other feature.
Keep exploring
Daily diaries with windows, reminders and compliance tracking. Free sandbox.