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Bråten LCH, Gjefsen E, Gervin K, Pripp AH, Skouen JS, Schistad E, Pedersen LM, Wigemyr M, Selmer KK, Aass HCD, Goll G, Brox JI, Espeland A, Grøvle L, Zwart JA, Storheim K. Cytokine Patterns as Predictors of Antibiotic Treatment Effect in Chronic Low Back Pain with Modic Changes: Subgroup Analyses of a Randomized Trial (AIM Study). J Pain Res 2023; 16:1713-1724. [PMID: 37252109 PMCID: PMC10224727 DOI: 10.2147/jpr.s406079] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 04/21/2023] [Indexed: 05/31/2023] Open
Abstract
Objective Randomized trials testing the effect of antibiotics for chronic low back pain (LBP) with vertebral bone marrow changes on MRI (Modic changes) report inconsistent results. A proposed explanation is subgroups with low grade discitis where antibiotics are effective, but there is currently no method to identify such subgroups. The objective of the present study was to evaluate whether distinct patterns of serum cytokine levels predict any treatment effect of oral amoxicillin at one-year follow-up in patients with chronic low back pain and Modic changes at the level of a previous lumbar disc herniation. Design We used data from an overpowered, randomized, placebo-controlled trial (the AIM study) that tested 100 days of oral 750 mg amoxicillin vs placebo three times daily in hospital outpatients with chronic (>6 months) LBP with pain intensity ≥5 on a 0-10 numerical rating scale and Modic changes type 1 (oedema type) or 2 (fatty type). We measured serum levels of 40 inflammatory cytokines at baseline and analysed six predefined potential predictors of treatment effect based on cytokine patterns in 78 randomized patients; three analyses with recursive partitioning, one based on cluster analysis and two based on principal component analyses. The primary outcome was the Roland-Morris Disability Questionnaire score at one-year follow-up in the intention to treat population. The methodology and overall results of the AIM study were published previously. Results The 78 patients were 25-62 years old and 47 (60%) were women. None of the three recursive partitioning analyses resulted in any suggested subgroups. Of all main analyses, the largest effect estimate (mean difference between antibiotic and placebo groups) was seen in a subgroup not predefined as of main interest (Cluster category 3+4; -2.0, 95% CI: -5.2-1.3, RMDQ points; p-value for interaction 0.54). Conclusion Patterns of inflammatory serum cytokine levels did not predict treatment effect of amoxicillin in patients with chronic LBP and Modic changes. Clinical Trial Registration Number ClinicalTrials.gov (identifier: NCT02323412).
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Affiliation(s)
- Lars Christian Haugli Bråten
- Department of Research and Innovation, Division of Clinical Neuroscience, Oslo University Hospital HF, Oslo, Norway
| | - Elisabeth Gjefsen
- Department of Research and Innovation, Division of Clinical Neuroscience, Oslo University Hospital HF, Oslo, Norway
- Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Kristina Gervin
- Department of Research and Innovation, Division of Clinical Neuroscience, Oslo University Hospital HF, Oslo, Norway
| | - Are Hugo Pripp
- Oslo Centre of Biostatistics and Epidemiology Research Support Services, Oslo University Hospital Ulleval, Oslo, Norway
| | - Jan Sture Skouen
- Department of Physical Medicine and Rehabilitation, Haukeland University Hospital, Bergen, Norway
| | - Elina Schistad
- Department of Physical Medicine and Rehabilitation, Oslo University Hospital HF, Oslo, Norway
| | - Linda Margareth Pedersen
- Department of Research and Innovation, Division of Clinical Neuroscience, Oslo University Hospital HF, Oslo, Norway
| | - Monica Wigemyr
- Department of Research and Innovation, Division of Clinical Neuroscience, Oslo University Hospital HF, Oslo, Norway
| | - Kaja Kristine Selmer
- Department of Research and Innovation, Division of Clinical Neuroscience, Oslo University Hospital HF, Oslo, Norway
| | | | - Guro Goll
- Center for Treatment of Rheumatic and Musculoskeletal Diseases (REMEDY), Diakonhjemmet Hospital, Oslo, Norway
| | - Jens Ivar Brox
- Department of Physical Medicine and Rehabilitation, Oslo University Hospital HF, Oslo, Norway
| | - Ansgar Espeland
- Department of Radiology, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Lars Grøvle
- Department of Rheumatology, Østfold Hospital Trust, Grålum, Norway
| | - John-Anker Zwart
- Department of Research and Innovation, Division of Clinical Neuroscience, Oslo University Hospital HF, Oslo, Norway
- Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Kjersti Storheim
- Department of Research and Innovation, Division of Clinical Neuroscience, Oslo University Hospital HF, Oslo, Norway
- Oslo Metropolitan University, Department of Physiotherapy, Oslo, Norway
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