BACK-on-LINE™: A Digital Pain Phenotyping Tool to Personalise Early Self-Management of Low Back Pain: Reliability and Validity in Working Adults.

Low back pain is a major cause of work-related disability, yet most workplace support offers only generic advice. Researchers have developed BACK-on-LINE, a digital self-assessment tool that helps working adults understand their specific type of back pain—whether it's primarily nociceptive (tissue-based) or nociplastic (sensitized nervous system pain). This study tested the tool's accuracy and reliability in 211 employed adults with low back pain from workplace settings. The tool successfully classified nearly 70% of participants as having nociceptive pain and about 32% as nociplastic. Results showed the tool was highly reliable when people took it multiple times, and it accurately identified important differences between pain types. People classified with nociplastic pain reported significantly higher pain levels, more disability, and greater psychological distress—all factors that matter for treatment planning. The tool performed as well as or better than existing screening questionnaires at predicting who would experience chronic pain or need time off work. This matters because different pain types may respond better to different treatments. For example, nociplastic pain often benefits from approaches addressing nervous system sensitivity, including stress management and gentle movement—areas where acupuncture may play a supportive role alongside other self-management strategies. By helping people understand their pain type earlier, BACK-on-LINE could guide more personalized self-care decisions in workplace settings. If considering acupuncture for low back pain, seek a licensed or certified acupuncturist with experience treating musculoskeletal conditions.

This validation study evaluated BACK-on-LINE, a self-administered digital phenotyping tool differentiating nociceptive and nociplastic low back pain in working populations (n=211 employed adults, 136 completed). The tool demonstrated strong psychometric properties: internal consistency (Cronbach's α=0.83), test-retest reliability (ICC=0.88), and moderate criterion validity (AUC=0.67-0.77) against pain intensity, disability, chronicity, and sickness absence. Of participants, 68.4% were classified as nociceptive and 31.6% as nociplastic. Known-groups validity was robust, with nociplastic subgroups showing significantly higher scores on pain (NPRS), disability (RMDQ), and psychosocial risk (SBST) (all p<0.001). Convergent validity was strongest with SBST (r=0.67). BACK-on-LINE matched or exceeded SBST's discriminative ability for workplace-relevant outcomes. Clinical implications: This tool enables early, scalable pain mechanism classification in occupational settings, potentially facilitating targeted self-management strategies. For acupuncture practitioners, identifying nociplastic presentations may inform treatment approach, as these patients present with higher disability and psychosocial complexity requiring multimodal, nervous system-focused interventions.