PT  - JOURNAL ARTICLE
AU  - Margreth Grotle
AU  - Lars Christian Bråten
AU  - Jens Ivar Brox
AU  - Ansgar Espeland
AU  - Zinajda Zolic-Karlsson
AU  - Rikke Munk Killingmo
AU  - Alexander Tingulstad
AU  - Lars Grøvle
AU  - Anne Froholdt
AU  - Per Martin Kristoffersen
AU  - Monica Wigemyr
AU  - Maurits W van Tulder
AU  - Kjersti Storheim
AU  - John-Anker Zwart
ED  - ,
TI  - Cost–utility analysis of antibiotic treatment in patients with chronic low back pain and Modic changes: results from a randomised, placebo-controlled trial in Norway (the AIM study)
AID  - 10.1136/bmjopen-2019-035461
DP  - 2020 Jun 01
TA  - BMJ Open
PG  - e035461
VI  - 10
IP  - 6
4099  - http://bmjopen.bmj.com/content/10/6/e035461.short
4100  - http://bmjopen.bmj.com/content/10/6/e035461.full
SO  - BMJ Open2020 Jun 01; 10
AB  - Objective To evaluate the cost–utility of 100 days of antibiotics in patients with chronic low back pain (LBP) and type I or II Modic changes included in the Antibiotic treatment In patients with chronic low back pain and Modic changes (AIM) study.Design A cost–utility analysis from a societal and healthcare perspective alongside a double-blinded, parallel group, placebo, multicentre trial.Setting Hospital outpatient clinics at six hospitals in Norway. The main results from the AIM study showed a small effect in back-related disability in favour of the antibiotics group, and slightly larger in those with type I Modic changes, but this effect was below the pre-defined threshold for clinically relevant effect.Participants 180 patients with chronic LBP, previous disc herniation and Modic changes type I (n=118) or type II (n=62) were randomised to antibiotic treatment (n=89) or placebo-control (n=91).Interventions Oral treatment with either 750 mg amoxicillin or placebo three times daily for 100 days.Main outcome measures Quality-adjusted life years (QALYs) by EuroQoL-5D over 12 months and costs for healthcare and productivity loss measured in Euro (€1=NOK 10), in the intention-to-treat population. Cost–utility was expressed in incremental cost-effectiveness ratio (ICER).Results Mean (SD) total cost was €21 046 (20 105) in the amoxicillin group and €19 076 (19 356) in the placebo group, mean difference €1970 (95% CI; −3835 to 7774). Cost per QALY gained was €24 625. In those with type I Modic changes, the amoxicillin group had higher healthcare consumption than the placebo group, resulting in €39 425 per QALY gained. Given these ICERs and a willingness-to-pay threshold of €27 500 (NOK 275 000), the probability of amoxicillin being cost-effective was 51%. Even when the willingness-to-pay threshold increased to €55 000, the probability of amoxicillin being cost-effective was never higher than 53%.Conclusions Amoxicillin treatment showed no evidence of being cost-effective for people with chronic LBP and Modic changes during 1-year follow-up.Trial registration number ClinicalTrials.gov NCT02323412.