Predicting high health care use in patients with spinal disorder in secondary care: model development and validation

Lise Grethe Kjønø; Karin Magnusson; Marianne Bakke Johnsen; Kjersti Storheim; Stine Haugaard Clausen; Maja Wilhelmsen; Søren O'Neill; Are Hugo Pripp; Bjørnar Berg; Christian Volmar Skovsgaard; Jan Hartvigsen; Margreth Grotle; Ørjan Nesse Vigdal

doi:10.1097/PR9.0000000000001382

Predicting high health care use in patients with spinal disorder in secondary care: model development and validation

Pain Rep. 2026 Jan 16;11(1):e1382. doi: 10.1097/PR9.0000000000001382. eCollection 2026 Feb.

Authors

Lise Grethe Kjønø¹, Karin Magnusson^{2

3}, Marianne Bakke Johnsen^{1

4}, Kjersti Storheim^{1

5}, Stine Haugaard Clausen⁶, Maja Wilhelmsen^{7

8}, Søren O'Neill^{9

10}, Are Hugo Pripp^{11

12}, Bjørnar Berg¹, Christian Volmar Skovsgaard¹³, Jan Hartvigsen^{6

14}, Margreth Grotle^{1

5}, Ørjan Nesse Vigdal¹

Affiliations

¹ Department of Rehabilitation Science and Health Technology, Faculty of Health Sciences, Oslo Metropolitan University, Oslo, Norway.
² Cluster for Health Services Research, Norwegian Institute of Public Health, Oslo, Norway.
³ Clinical Epidemiology Unit, Department of Clinical Sciences, Orthopaedics, Faculty of Medicine, Lund University, Lund, Sweden.
⁴ Department of Physical Medicine and Rehabilitation, Oslo University Hospital, Oslo, Norway.
⁵ Division of Clinical Neuroscience, Department of Research and Innovation, Oslo University Hospital, Oslo, Norway.
⁶ Center for Muscle and Joint Health, Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark.
⁷ Faculty of Health Sciences, Department of Clinical Medicine, UiT-The Arctic University of Norway, Tromsø, Norway.
⁸ Department of Rehabilitation, University Hospital of North Norway, Tromsø, Norway.
⁹ Medical Spinal Research Unit, Spine Centre of Southern Denmark, Lillebaelt Hospital - University Hospital of Southern Denmark, Kolding, Denmark.
¹⁰ Department of Regional Health Research, University of Southern Denmark, Odense, Denmark.
¹¹ Faculty of Health Sciences, Oslo Metropolitan University, Oslo, Norway.
¹² Oslo Centre of Biostatistics and Epidemiology, Research Support Services, Oslo University Hospital, Oslo, Norway.
¹³ Department of Public Health, Danish Centre for Health Economics, University of Southern Denmark, Odense, Denmark.
¹⁴ Chiropractic Knowledge Hub, Odense, Denmark.

Abstract

Introduction: Spinal disorders are among the biggest contributors to health care utilization (HCU).

Objective: To develop and externally validate a prediction model for high all-cause HCU (75th percentile during 1 year after the index date) among patients with spinal disorders visiting multidisciplinary secondary care clinics.

Methods: We developed and internally validated the model using the Norwegian Neck and Back Registry, including patients registered between January 1, 2016, and December 31, 2020, linked with national health registries (N = 9092). For external validation, we used data from the Danish SpineData Registry, linked with national registries, for the same period (N = 34,853). We assessed Nagelkerke R ² , discrimination (area under receiver operating characteristics curve [AUC]), and calibration (calibration-in-the-large [CITL], slope, and calibration plot).

Results: The final model included sex, nationality, education, physical activity, smoking, prior HCU, work status, disability, health-related quality of life, medicine use, diagnosis, kinesiophobia, and comorbidity. It demonstrated acceptable discrimination (AUC 0.78, 95% confidence interval [CI], 0.77-0.78), an R ² of 0.26, and good calibration after internal validation. Upon external validation, the model demonstrated excellent discrimination (AUC 0.81, 95% CI 0.80-0.81) and an R ² of 0.31. The calibration slope was 1.08 (95% CI 1.06-1.11) and CITL was 0.16 (95% CI 0.12-0.19). Predicted probabilities closely matched observed probabilities across all deciles in internal validation, with slight underestimation of high HCU in the top 3 deciles during external validation.

Conclusion: Overall, the model shows promise in predicting high HCU in patients with spinal disorders referred to secondary care but requires further testing and validation in implementation settings before recommendation.

Keywords: Epidemiology; High health care utilization; Prediction model; Registry data; Spinal disorders; Validation.