Low Back PainNCT00667316
The Influence of Different Factors on Workers' Disability Due to Low Back Pain
An observational study of Low Back Pain, run by Kovacs Foundation at 1 site in Spain.
Trial summary
The purpose of this study is to determine, in Spanish workers, the influence of different factors (personal, psychological, work related and clinical) on the risk of being on sick leave during the 18 months after baseline assessment, and on the duration of that sick leave. Read more about this study
- Who is it for?
- Ages 18 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- Low Back Pain
- What is being tested?
- Set of questionnaires (respondent)
- Type of treatment
- Lifestyle or therapy programme
- How many people
- 7,300 participants
- Where
- 1 siteSpain
- Study dates
- Feb 2008to Dec 2021
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 65 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Study population: Workers from companies and workers' health care organizations who are currently active.
Who may be able to join
- Subjects who get their checkups at participating health services
- With a labor contract that won't make it likely that they stop work before the next 18 months, for causes other than their health
- Who sign the informed consent form
Who cannot join
- Don't sign the informed consent form
- Inability to fill our the questionnaires
- Bedridden
- Rheumatologic inflammatory disease, cancer or fibromyalgia
- Suspicion of fibromyalgia
- Red flags for systemic disease
- Criteria for surgery
- Criteria for urgent referral to surgery
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Study to Identify the Influence of Different Factors on Workers' Disability Due to Low Back Pain
The purpose of this study is to determine, in Spanish workers, the influence of different factors (personal, psychological, work related and clinical) on the risk of being on sick leave during the 18 months after baseline assessment, and on the duration of that sick leave.
- Conditions
- Low Back Pain
- Being tested
- Set of questionnaires (respondent)
- Keywords
- low back pain, workers, disability, sick leave
- Medical subject headings
- Low Back Pain
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Set of questionnaires (respondent)Behavioural
A set of questionnaires to determine risk factors for sick leave due to low back pain.
| Study group | Role | What they receive |
|---|---|---|
| A | Workers from companies and workers' health care organizations who go for their periodic medical checkup. Receives: Behavioral: Set of questionnaires (respondent) |
What is being measured
The primary outcome is the main question the study is designed to answer.
The influence of different factors on risk of sick leave for low back pain
Measured: 18 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 Apr 2008 (estimated)
- Study startFeb 2008
- Primary completionJun 2021
- Study completionDec 2021
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (4)Papers the sponsor has linked to this study.
- Other trials for Low Back PainStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Other
- Time perspective
- Prospective
- Enrolment
- 7,300 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Kovacs Foundation
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Francisco M. Kovacs, Kovacs Foundation
- Investigators
- Francisco M Kovacs, MD, PhD, Study director, Kovacs Foundation, Palma de Mallorca, 07012, SpainMario Gestoso, MD, Principal investigator, Kovacs Foundation,Palma de Mallorca, Spain
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00667316
- Sponsor's protocol ID
- FK-I-25
- Status last verified
- Aug 2025
- First submitted
- 24 Apr 2008
- Last updated
- 4 Sep 2025
- Results posted
- No
- Data monitoring committee
- Yes
Publications
Guo HR, Tanaka S, Cameron LL, Seligman PJ, Behrens VJ, Ger J, Wild DK, Putz-Anderson V. Back pain among workers in the United States: national estimates and workers at high risk. Am J Ind Med. 1995 Nov;28(5):591-602. doi: 10.1002/ajim.4700280504.
PubMed 8561169Turner JA, Franklin G, Fulton-Kehoe D, Sheppard L, Wickizer TM, Wu R, Gluck JV, Egan K. Worker recovery expectations and fear-avoidance predict work disability in a population-based workers' compensation back pain sample. Spine (Phila Pa 1976). 2006 Mar 15;31(6):682-9. doi: 10.1097/01.brs.0000202762.88787.af.
PubMed 16540874Kovacs FM, Muriel A, Castillo Sanchez MD, Medina JM, Royuela A; Spanish Back Pain Research Network. Fear avoidance beliefs influence duration of sick leave in Spanish low back pain patients. Spine (Phila Pa 1976). 2007 Jul 15;32(16):1761-6. doi: 10.1097/BRS.0b013e3180b9f5f7.
PubMed 17632397Seco-Calvo J, Royuela A, Rodriguez-Perez V, Kovacs F. Predicting low back pain-related absenteeism in the Spanish general working population. Occup Environ Med. 2026 Jan 21;82(11):547-555. doi: 10.1136/oemed-2025-110435.
PubMed 41443770
Study at a glance
From the registry record, last updated by the sponsor on 4 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Study to Identify the Influence of Different Factors on Workers' Disability Due to Low Back Pain
- ClinicalTrials.gov ID
- NCT00667316
- Acronym / sponsor ID
- FK-I-25
- Conditions
- Low Back Pain
- Keywords
- low back pain, workers, disability, sick leave
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 7,300 participants (estimated)
- Lead sponsor
- Kovacs FoundationUniversity, hospital or other
- Study start
- Feb 2008
- Primary completion
- Jun 2021 (actual)
- Study completion
- Dec 2021 (actual)
- First posted
- 28 Apr 2008 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this study is to determine, in Spanish workers, the influence of different factors (personal, psychological, work related and clinical) on the risk of being on sick leave during the 18 months after baseline assessment, and on the duration of that sick leave.
Study design
- Observational model
- Other
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| A | – | Behavioral: Set of questionnaires (respondent)Workers from companies and workers' health care organizations who go for their periodic medical checkup. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- Workers from companies and workers' health care organizations who are currently active.
Key inclusion criteria (3 listed)
- Subjects who get their checkups at participating health services
- With a labor contract that won't make it likely that they stop work before the next 18 months, for causes other than their health
- Who sign the informed consent form
Key exclusion criteria (8 listed)
- Don't sign the informed consent form
- Inability to fill our the questionnaires
- Bedridden
- Rheumatologic inflammatory disease, cancer or fibromyalgia
- Suspicion of fibromyalgia
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Set of questionnaires (respondent)A set of questionnaires to determine risk factors for sick leave due to low back pain. | Behavioural | A |
Primary outcome
The influence of different factors on risk of sick leave for low back pain
Time frame: 18 months
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 4 Sep 2025.
- Background: PubMed 8561169Guo HR, Tanaka S, Cameron LL, Seligman PJ, Behrens VJ, Ger J, Wild DK, Putz-Anderson V. Back pain among workers in the United States: national estimates and workers at high risk. Am J Ind Med. 1995 Nov;28(5):591-602. doi: 10.1002/ajim.4700280504.
- Background: PubMed 16540874Turner JA, Franklin G, Fulton-Kehoe D, Sheppard L, Wickizer TM, Wu R, Gluck JV, Egan K. Worker recovery expectations and fear-avoidance predict work disability in a population-based workers' compensation back pain sample. Spine (Phila Pa 1976). 2006 Mar 15;31(6):682-9. doi: 10.1097/01.brs.0000202762.88787.af.
- Background: PubMed 17632397Kovacs FM, Muriel A, Castillo Sanchez MD, Medina JM, Royuela A; Spanish Back Pain Research Network. Fear avoidance beliefs influence duration of sick leave in Spanish low back pain patients. Spine (Phila Pa 1976). 2007 Jul 15;32(16):1761-6. doi: 10.1097/BRS.0b013e3180b9f5f7.
- Derived from this study: PubMed 41443770Seco-Calvo J, Royuela A, Rodriguez-Perez V, Kovacs F. Predicting low back pain-related absenteeism in the Spanish general working population. Occup Environ Med. 2026 Jan 21;82(11):547-555. doi: 10.1136/oemed-2025-110435.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Francisco M Kovacs, MD, PhD study director
Kovacs Foundation, Palma de Mallorca, 07012, Spain
Mario Gestoso, MD principal investigator
Kovacs Foundation,Palma de Mallorca, Spain
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Low Back Pain, run by Kovacs Foundation at 1 site in Spain.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 4 Sep 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Spain. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
The influence of different factors on risk of sick leave for low back pain (time frame: 18 months). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT00667316, which also lists 4 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 4 Sep 2025.