Characteristics and outcomes of patients who did not respond to a national spine surgery registry

Simran Kaur; Ole Kristian Alhaug; Filip C Dolatowski; Tore K Solberg; Greger Lønne

doi:10.1186/s12891-023-06267-3

Characteristics and outcomes of patients who did not respond to a national spine surgery registry

BMC Musculoskelet Disord. 2023 Mar 4;24(1):164. doi: 10.1186/s12891-023-06267-3.

Authors

Simran Kaur¹, Ole Kristian Alhaug^{2

3

4}, Filip C Dolatowski⁵, Tore K Solberg^{6

7}, Greger Lønne^{2

4}

Affiliations

¹ Department of Orthopedic Surgery, Martina Hansens Hospital, Sandvika, Norway. Simran.85.k@gmail.com.
² Innlandet Hospital Trust, Brumunddal, Norway.
³ Akershus University Hospital, Nordbyhagen, Norway.
⁴ Norwegian University of Science and Technology, Trondheim, Norway.
⁵ Division of Orthopedic Surgery, Oslo University Hospital, Oslo, Norway.
⁶ Department of Neurosurgery & Norwegian Registry for Spine surgery, University Hospital of North Norway, Tromsø, Norway.
⁷ Department of Clinical Medicine, The Arctic University of Norway (UiT), Tromsø, Norway.

Abstract

Background: Loss to follow-up may bias outcome assessments in medical registries. This cohort study aimed to analyze and compare patients who failed to respond with those that responded to the Norwegian Registry for Spine Surgery (NORspine).

Methods: We analyzed a cohort of 474 consecutive patients operated for lumbar spinal stenosis at four public hospitals in Norway during a two-year period. These patients reported sociodemographic data, preoperative symptoms, and Oswestry Disability Index (ODI), numerical rating scales (NRS) for back and leg pain to NORspine at baseline and 12 months postoperatively. We contacted all patients who did not respond to NORspine after 12 months. Those who responded were termed responsive non-respondents and compared to 12 months respondents.

Results: One hundred forty (30%) did not respond to NORspine 12 months after surgery and 123 were available for additional follow-up. Sixty-four of the 123 non-respondents (52%) responded to a cross-sectional survey done at a median of 50 (36-64) months after surgery. At baseline, non-respondents were younger 63 (SD 11.7) vs. 68 (SD 9.9) years (mean difference (95% CI) 4.7 years (2.6 to 6.7); p = < 0.001) and more frequently smokers 41 (30%) vs. 70 (21%) RR (95%CI) = 1.40 (1.01 to 1.95); p = 0.044. There were no other relevant differences in other sociodemographic variables or preoperative symptoms. We found no differences in the effect of surgery on non-respondents vs. respondents (ODI (SD) = 28.2 (19.9) vs. 25.2 (18.9), MD (95%CI) = 3.0 ( -2.1 to 8.1); p = 0.250).

Conclusion: We found that 30% of patients did not respond to NORspine at 12 months after spine surgery. Non-respondents were somewhat younger and smoked more frequently than respondents; however, there were no differences in patient-reported outcome measures. Our findings suggest that attrition bias in NORspine was random and due to non-modifiable factors.

Keywords: Attrition bias; Loss to follow-up; Lumbar spinal stenosis; Non-response; Registry; Spine surgery.

MeSH terms

Cohort Studies
Cross-Sectional Studies
Humans
Norway
Outcome Assessment, Health Care*
Registries