Table 3.
Baseline (preindex) clinical characteristics of the study cohorts
| Variable | SCI-NeP n=546 | SCI only n=546 | P |
|---|---|---|---|
| Type of SCI, %a | |||
| Quadriplegia/quadriparesis | 20.3 | 23.8 | 0.166 |
| Paraplegia | 31.1 | 35.0 | 0.177 |
| Cauda equina syndrome | 10.6 | 11.5 | 0.630 |
| Vertebral column fracture | 17.0 | 19.6 | 0.273 |
| SCI without spinal bone injury | 29.1 | 32.4 | 0.238 |
| Trauma-related SCIb | 30.4 | 22.3 | 0.003 |
| Comorbidity indexes, mean (SD) | |||
| Deyo-Charlson Comorbidity Index | 1.7 (2.0) | 1.8 (2.2) | 0.420 |
| ICD-9-CM diagnosesc | 18.0 (10.7) | 17.6 (10.4) | 0.466 |
| Outpatient medicationsd | 10.2 (8.8) | 10.6 (8.4) | 0.553 |
| Comorbid conditions, % | |||
| Musculoskeletal pain | 49.8 | 50.0 | 0.952 |
| Gastrointestinal conditionse | 36.3 | 35.5 | 0.801 |
| Hypertension | 32.2 | 34.1 | 0.520 |
| Substance abuse | 28.2 | 26.7 | 0.588 |
| Respiratory conditionsf | 22.3 | 20.9 | 0.556 |
| Renal/bladder conditionsg | 21.4 | 20.1 | 0.602 |
| Anxiety | 17.4 | 15.0 | 0.286 |
| Diabetes | 14.3 | 16.8 | 0.243 |
| Arthritis (osteoarthritis and rheumatoid arthritis) | 12.6 | 13.6 | 0.654 |
| Depression | 10.8 | 8.2 | 0.149 |
| Insomnia/sleep disorders | 7.9 | 7.5 | 0.820 |
| Atherosclerosis | 6.4 | 6.4 | 1.000 |
| Deep-vein thrombosis | 5.7 | 4.8 | 0.496 |
| Medications, % | |||
| Opioid analgesics – short-acting | 68.5 | 70.1 | 0.555 |
| Muscle relaxants | 35.9 | 34.4 | 0.612 |
| Anxiolytics | 34.8 | 32.4 | 0.405 |
| NSAIDs | 32.6 | 33.2 | 0.847 |
| Non-NeP antidepressants | 23.8 | 23.8 | 1.000 |
| Steroids (systemic) | 15.9 | 15.9 | 1.000 |
| Sedative/hypnotics | 15.8 | 13.7 | 0.348 |
| Opioid analgesics – long-acting | 11.4 | 7.7 | 0.039 |
| Non-NeP antiepileptics | 9.5 | 7.9 | 0.334 |
| Topical analgesics | 4.0 | 3.8 | 0.876 |
| SCI- and pain-related procedures, % | |||
| Spinal cord surgery | 4.6 | 6.8 | 0.117 |
| Spine decompression | 12.8 | 7.0 | 0.001 |
| Stabilization of the spine | 10.4 | 6.2 | 0.012 |
| Pain intervention procedure | 23.8 | 24.9 | 0.672 |
Notes:
Total proportion exceeds 100% since there is some overlap among the SCI types
traumatic-SCI was defined as an ICD-9-CM diagnosis code of 806.xx or 907.2x at any time on or after the initial SCI diagnosis
count of unique three-digit ICD-9-CM codes on medical claims
count of unique outpatient medications
gastrointestinal conditions include irritable bowel syndrome, abdominal pain, gastroesophageal reflux disease, ulcers, neurogenic bowel, and constipation
respiratory conditions include respiratory failure, pulmonary embolism, pneumonia, and chronic obstructive pulmonary disease
renal/bladder conditions include neurogenic bladder, urinary tract infection, and urinary calculi.
Abbreviations: ICD-9-CM, International Classification of Diseases, Ninth Revision, Clinical Modification; NeP, neuropathic pain; NSAIDs, nonsteroidal anti-inflammatory drugs; SCI, spinal cord injury; SD, standard deviation.