Autonomic–anxiety symptoms of dysfunctional breathing in females with low back pain: A Nijmegen questionnaire-based secondary analysis in primary care

Background Low back pain (LBP) is associated with psychological and breathing symptoms, such as dysfunctional breathing (DB) and hyperventilation syndrome (HVS), possibly more evident in females through autonomic–anxiety mechanisms. Objective To estimate the frequency of a positive screening result for a probable HVS/DB symptom profile among females with LBP using the Nijmegen Questionnaire (NQ), compare features and autonomic–anxiety symptoms across screening-defined groups (HVS + /HVS – ), and explore associations between features and the NQ total score (NQ_total) and an autonomic–anxiety subscale (NQ_AA). Methods This exploratory secondary analysis included 87 females with LBP from a cross-sectional primary care study, assessing age, body mass index (BMI), pain duration, pain intensity, and NQ scores; NQ ≥20 was used as a pragmatic screening threshold. Group differences and associations were analysed using nonparametric tests, with multivariable regression for NQ_AA and exploratory PCA to examine symptom structure. Results Fifty-one per cent of participants screened positive for a probable HVS/DB symptom profile. The HVS + group had significantly higher NQ_total and NQ_AA scores, with no differences in age, BMI, pain duration, or pain intensity. The only consistent finding was a modest positive association between pain intensity and NQ_AA, which remained the sole independent correlate despite the model explaining little variance. PCA suggested a two-component structure, separating respiratory and autonomic–anxiety symptoms, explaining 40.7% of variance. Conclusion A probable HVS/DB symptom profile was common in the sample and primarily reflected a higher autonomic–anxiety symptom burden. NQ may provide complementary information during assessment, but findings should be interpreted cautiously and require further confirmation.