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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Type of registration
Prospectively registered

Titles & IDs
Public title
Oral steroids in sciatica: The OASIS Randomised Controlled Trial
Scientific title
OASIS, a two-arm, double-blind randomised controlled trial of oral steroids in addition to usual care compared to placebo for reducing leg pain in patients with acute sciatica.
Secondary ID [1] 299822 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Sciatica 315204 0
Condition category
Condition code
Musculoskeletal 313525 313525 0 0
Other muscular and skeletal disorders

Study type
Description of intervention(s) / exposure
Oral prednisolone plus guideline-recommended advice.
Initial dose of 50 mg/day for a maximum 3 days, followed by 25 mg/day for a maximum of 5 days, then 12.5mg/day for a maximum of 5 days before complete cessation. The maximum duration from commencement to cessation will be 13 days and the maximum cumulative dose 337.5 mg. The dose can be adjusted by the study doctor depending on individual progress and tolerability. For example, if a participant experiences side effects (e.g. difficulty sleeping), the initial dose can be lowered to 25 mg per day. If a participant reaches ‘adequate improvement’ (0 to 1 out of 10 pain for three consecutive days), dose reduction can start earlier.
Adherence to study medication will be monitored by a self-report daily medication diary and by counting the returned medications against the doctor’s prescription record.
Additionally, all participants will receive guideline-recommended advice from their study doctor, such as patient reassurance (of the benign pathology and prognosis), staying active and avoiding bed rest and complex medicines.
Intervention code [1] 316081 0
Treatment: Drugs
Comparator / control treatment
Placebo plus guideline-recommended advice.
The placebo tablet will be identical in appearance to the prednisolone and will consist of Microcrystalline Cellulose USP, Colloidal Silicon Dioxide USP, Sodium Starch Glycolate USP, Sodium Stearyl Fumarate USP.
The treatment regimen is the same as the intervention treatment of prednisolone (as described above). Participants will also receive guideline-recommended advice as per the intervention arm.
Control group

Primary outcome [1] 321972 0
Leg pain intensity measured by the numerical rating scale.
Timepoint [1] 321972 0
Baseline, weeks 2 (primary endpoint), 6, 12, 26 and 52.
Secondary outcome [1] 376871 0
Disability measured by the Roland Morris Disability Scale for Sciatica.
Timepoint [1] 376871 0
Baseline, weeks 2, 6, 12, 26 and 52.
Secondary outcome [2] 376872 0
Back Pain intensity measured by the numerical rating scale
Timepoint [2] 376872 0
Baseline, weeks 2, 6, 12, 26 and 52
Secondary outcome [3] 376873 0
Quality of life measured by the Short Form-12.
Timepoint [3] 376873 0
Baseline, weeks 2, 6, 12, 26 and 52.
Secondary outcome [4] 376874 0
Time to recovery (defined as the first of 7 consecutive days of 0 to 1 out of 10 pain) measured by a pain diary.
Timepoint [4] 376874 0
For a maximum or 3 week or until recovery whichever occurs later. Participants will be followed up for 52 weeks if recovery does not occur within this time.
Secondary outcome [5] 376875 0
Adverse events assessed by the question “Have you experienced any adverse events, a new medical condition or a worsening of an existing medical condition since starting the study treatment, for example, dizziness or sweating?” The most common possible side effects of prednisolone when used for a short time include nausea, vomiting, increased appetite, anorexia, stomach bloating or irritation, diarrhoea or constipation, mood or behavioural changes (e.g. mood swings, anxiety, restlessness, trouble sleeping).
Timepoint [5] 376875 0
Weeks 2, 6 and 12 post-randomisation
Secondary outcome [6] 376876 0
Work absenteeism and use of other treatments or health care services measured by a questionnaire specifically designed for the study. E.g. at Week 2: a) “Did you miss any hours off your normal paid work in the last 2 weeks due to your sciatica?”; b) “Did you use any healthcare services (e.g. GP, physiotherapy, x-rays, hospital admission), or community health or other services (e.g. meals on wheels) in the last 2 weeks due to your sciatica?”
Timepoint [6] 376876 0
Weeks 2, 6, 12, 26, 52 post-randomisation
Secondary outcome [7] 376877 0
Adherence to study medication measured by a self-report daily medication diary and by counting the returned medications against the doctor’s prescription record.
Timepoint [7] 376877 0
Week 2 post-randomisation

Key inclusion criteria
Adults with acute sciatica (no more than 6 weeks since onset) of at least moderate pain intensity in leg pain or results in at least moderate interference with daily activities during the previous week. Sciatica is defined as radiating pain into one leg below the knee, accompanied by lumbar nerve root or spinal-nerve involvement as indicated by the presence of at least one of these clinical features: dermatomal leg pain, myotomal weakness, sensory deficits, or diminished reflex.
Minimum age
18 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Known or suspected serious disease of the spine (e.g. cauda equina syndrome); planning to undergo spinal surgery or other interventional procedures (e.g. an epidural injection) for sciatica during the treatment period; having had spinal surgery or other interventional procedures (e.g. an epidural injection) in the preceding 6 months; having used a systemic glucocorticoid (for any condition) via any method of administration since the start of this episode of sciatica; contraindications to glucocorticoids (e.g. known allergy to prednisolone, active infection, diabetes, pre-diabetes and previous history of gestational diabetes, active gastrointestinal bleeding (peptic ulcer), uncontrolled hypertension and heart failure, psychosis, immunosuppression) or precautions to glucocorticoids where risks outweigh potential benefits; for females: pregnant, breast-feeding, or planning conception during the treatment period.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
The participant will be enrolled into the study after the informed consent process has been completed and the participant has met all inclusion criteria and none of the exclusion criteria. The participant will receive a study medication pack with a unique study ID number. This is where randomisation will occur. Allocation to group will be concealed and participants will be randomised to either the treatment group (oral prednisolone) or placebo group.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Allocation sequence will be prepared a priori using a computerised random number generator by an independent statistician not involved in participant recruitment, treatment or data collection, in permuted blocks. Study medication packs will be prepared according to the allocation sequence and sealed.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s
The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Other design features
Phase 4
Type of endpoint(s)
Statistical methods / analysis
Data analysis will be blinded, by intention-to-treat and guided by a detailed statistical analysis plan. Analysis will be conducted by the research team and by an independent biostatistician, and checked for accuracy. The primary analysis will assess the effect of treatment group on leg pain intensity at Week 2 using a linear regression model, with baseline pain as a covariate (ANCOVA).
For all secondary continuous outcomes measured at Weeks 2, linear regression models will be used as per the primary analysis. For effects on the primary and all secondary continuous outcomes at Weeks 6, 12, 26 and 52, longitudinal linear models will be used with the baseline value included as a covariate. Correlations between repeated measures will be accounted for using generalised estimating equations. Time to recovery of pain will be analysed using a survival model.
We will also conduct a cost-effectiveness analysis.

Recruitment status
Not yet recruiting
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)

Funding & Sponsors
Funding source category [1] 304283 0
Government body
Name [1] 304283 0
NHMRC Project Grant
Address [1] 304283 0
Level 1
16 Marcus Clarke Street
Canberra ACT 2601
Country [1] 304283 0
Primary sponsor type
The University of Sydney
Missenden Road, Camperdown
NSW 2050
Secondary sponsor category [1] 304526 0
Name [1] 304526 0
Address [1] 304526 0
Country [1] 304526 0

Ethics approval
Ethics application status
Ethics committee name [1] 304740 0
Human Research Ethics Committee, The University of Sydney
Ethics committee address [1] 304740 0
Human Ethics Office
Margaret Telfer Building (K07)
University of Sydney
NSW 2006
Ethics committee country [1] 304740 0
Date submitted for ethics approval [1] 304740 0
Approval date [1] 304740 0
Ethics approval number [1] 304740 0

Brief summary
This study aims to investigate the efficacy of oral glucocorticoids in reducing leg pain intensity in people with acute sciatica. Participants will be randomised to receive either active medication (oral prednisolone) or placebo for up to 13 days (from commencement to cessation). We hypothesise that orally administered glucocorticoids will produce a clinically worthwhile improvement in leg pain.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 98046 0
A/Prof Christine Lin
Address 98046 0
Institute for Musculoskeletal Health, School of Public Health, The University of Sydney, PO Box M179 Missenden Rd NSW 2050
Country 98046 0
Phone 98046 0
+61 286276237
Fax 98046 0
Email 98046 0
Contact person for public queries
Name 98047 0
Dr Juliana S Oliveira
Address 98047 0
Institute for Musculoskeletal Health, School of Public Health, The University of Sydney, PO Box M179 Missenden Rd NSW 2050
Country 98047 0
Phone 98047 0
+61 286276389
Fax 98047 0
Email 98047 0
Contact person for scientific queries
Name 98048 0
Dr Juliana S Oliveira
Address 98048 0
Institute for Musculoskeletal Health, School of Public Health, The University of Sydney, PO Box M179 Missenden Rd NSW 2050
Country 98048 0
Phone 98048 0
+61 286276389
Fax 98048 0
Email 98048 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
What data in particular will be shared?
De-identified individual participant data will be made available on request. Different aspects of the data will be published separately, which will determine when particular information is publicly available.
When will data be available (start and end dates)?
Data for this trial will be available on request soon after each report of the data has been published. There will be no end date for availability of data.
Available to whom?
Data will be available to researchers who provide a methodologically sound proposal for its use and have ethical approval, and will be based on a case-by-case as decided by the Primary Investigators.
Available for what types of analyses?
How or where can data be obtained?
Access subject to approvals by Principal Chief Investigator (
What supporting documents are/will be available?
Study protocol
Statistical analysis plan
Ethical approval
How or where can supporting documents be obtained?
Type [1] 5770 0
Study protocol
Citation [1] 5770 0
Link [1] 5770 0
Email [1] 5770 0
Other [1] 5770 0
Attachment [1] 5770 0
Type [2] 5771 0
Statistical analysis plan
Citation [2] 5771 0
Link [2] 5771 0
Email [2] 5771 0
Other [2] 5771 0
Attachment [2] 5771 0
Type [3] 5772 0
Ethical approval
Citation [3] 5772 0
Link [3] 5772 0
Email [3] 5772 0
Other [3] 5772 0
Attachment [3] 5772 0
Summary results
No Results