Are there sex and gender differences in low back pain interventions of randomized controlled trials? A meta-research study

Introduction

Low back pain (LBP) is the leading cause of Years Lived with Disability worldwide. The global prevalence of LBP is higher among females compared with males across all age groups (1). To improve LBP management, various rehabilitation interventions recommended by high quality clinical practice guidelines are effective (2). However, treatment effects can be different in male and female. This can also depend on the recruitments of participants in the randomized controlled trials (RCTs). Thus, we investigated the prevalence of different sex and gender participants in LBP trials to improve knowledge in sex and gender differences, enhancing tailored healthcare and external validity of randomized controlled trials.

Methods

We performed a cross-sectional meta-research study starting from 46 RCTs included in a recent published network meta-analysis (3) about the effectiveness and safety of pharmacological and non-pharmacological interventions in acute and subacute LBP. We extracted data on the percentage of different sex and gender participants and the sex balance (i.e., defined as 45%-55% of women participation) in each treatment intervention. We also assessed if studies reported outcome data according to sex and/or gender.

Results

Overall, 45 RCTs (98%) provided information about sex (86.7% in general population, 13.3% in work-related population) for 14 treatment interventions in 85 arms. No study reported data on gender (i.e.., sex and gender terms were used interchangeably). More than half study arms (56.4%) were sex unbalanced, favoring more men in 58.3%. Median percentage of women was 48% (IQR 40%-54.6%) in the general population (n=75 arms of interventions) and 47.2% (8.6%-53.3%) in the work-related population (n=10 arms). In the general population, women were less recruited in cognitive behavioral interventions (35.5%) while more recruited in heat wrap (59.5%). In the work-related population, women were less recruited in back school interventions (8.6%) while more recruited in exercise (57.2%) (Figure 1). Only two studies reported outcome data considering sex.

Discussion and Conclusion

Women seem to be under-represented in some interventions delivered for LBP, with unbalanced recruitment in more than half studies. We call for balancing the enrollment of different sex and gender participants in clinical research to ensure that LBP interventions are equally safe and effective for all patients.

REFERENCES

1. Collaborators GBDLBP. Global, regional, and national burden of low back pain, 1990-2020, its attributable risk factors, and projections to 2050: a systematic analysis of the Global Burden of Disease Study 2021. Lancet Rheumatol. 2023;5(6):e316-e29.

2. Oliveira CB, Maher CG, Pinto RZ, Traeger AC, Lin CC, Chenot JF, van Tulder M, Koes BW. Clinical practice guidelines for the management of non-specific low back pain in primary care: an updated overview. Eur Spine J. 2018 Nov;27(11):2791-2803.

3. Gianola S, Bargeri S, Del Castillo G, Corbetta D, Turolla A, Andreano A, et al. Effectiveness of treatments for acute and subacute mechanical non-specific low back pain: a systematic review with network meta-analysis. Br J Sports Med. 2022;56(1):41-50.

Taggatoorale

Ci sono differenze di sesso e genere negli interventi valutati dagli studi randomizzati controllati sulla lombalgia? Uno studio di meta-ricerca