Table 1.
Patient sociodemographic and clinical characteristics
| Visits within 1 year | ||||||
|---|---|---|---|---|---|---|
| Variable | Total | 1 Visit | 2–3 Visits | 4–6 Visits | 7+ Visits | p Value |
| N | 19,946 | 5473 (27.4) | 5233 (26.2) | 4280 (21.5) | 4960 (24.9) | |
| Age, median [IQR], y | 45 [30–58] | 44 [29–57] | 44 [30–58] | 46 [30–59] | 47 [34–59] | < .00001 |
| Sex | ||||||
| Female | 13.5 | 25.6 | 24.6 | 21.9 | 27.9 | < .001 |
| Male | 86.5 | 27.7 | 26.5 | 21.4 | 24.4 | |
| Index Chiropractic Visit Diagnosis | < .00001 | |||||
| Low Back Pain Only | 55.6 | 30.5 | 26.3 | 21.1 | 22.2 | |
| Neck Pain Only | 9.0 | 27.6 | 26.3 | 21.6 | 24.5 | |
| Both Low Back and Neck Pain | 31.3 | 20.5 | 26.5 | 22.2 | 30.8 | |
| Neither Low Back nor Neck Pain | 4.1 | 39.1 | 24.0 | 20.4 | 16.4 | |
| Race | < .00001 | |||||
| White | 70.7 | 26.8 | 26.1 | 21.4 | 25.7 | |
| Black | 12.2 | 28.0 | 25.1 | 21.8 | 25.2 | |
| Hispanic | 7.7 | 27.0 | 27.8 | 22.7 | 22.5 | |
| Other | 2.4 | 26.7 | 23.6 | 24.4 | 25.4 | |
| Unknown | 7.1 | 33.6 | 28.5 | 19.0 | 18.9 | |
| Pain intensity, median [IQR] a | 4 [0–6] | 4 [0–6] | 4 [0–6] | 4 [0–6] | 4 [1–7] | 0.057 |
| No Pain or Mild Pain Intensity (NRS 0–3) | 44.3 | 28.8 | 26.6 | 21.2 | 23.4 | 0.190 |
| Moderate to Severe Pain Intensity (NRS 4–10) | 55.7 | 28.0 | 26.0 | 21.2 | 24.8 | |
| Smoking Status b | < .00001 | |||||
| Never | 36.3 | 27.4 | 25.4 | 21.5 | 25.7 | |
| Former | 39.9 | 27.9 | 27.8 | 21.3 | 23.0 | |
| Current | 23.8 | 23.8 | 25.8 | 22.4 | 28.0 | |
| BMI, mean (SD), kg/m2 c | 29.4 (5.4) | 29.1 (5.2) | 29.1 (5.4) | 29.1 (5.4) | 29.3 (5.4) | 0.054 |
| Not obese, BMI < 30 kg/m2 | 61.6 | 27.5 | 26.1 | 21.8 | 24.6 | 0.311 |
| Obese, BMI ≥ 30 kg/m2 | 38.4 | 27.1 | 26.4 | 20.9 | 25.5 | |
| Period of Service | < .00001 | |||||
| OEF/OIF/OND | 29.7 | 28.9 | 28.1 | 21.1 | 21.9 | |
| Gulf War | 24.3 | 29.1 | 25.7 | 20.8 | 24.4 | |
| Post-Vietnam Era | 12.8 | 25.9 | 25.2 | 22.2 | 26.7 | |
| Vietnam | 26.9 | 25.9 | 25.1 | 21.7 | 27.3 | |
| Other | 6.4 | 23.5 | 26.5 | 23.3 | 26.7 | |
| Marital Status | < .01 | |||||
| Married | 49.1 | 27.6 | 25.9 | 21.2 | 25.4 | |
| Not Married | 19.5 | 28.3 | 26.8 | 21.9 | 23.0 | |
| Separated/Divorced | 28.5 | 26.5 | 26.6 | 21.8 | 25.1 | |
| Widow/Widower | 2.3 | 25.3 | 25.8 | 20.9 | 28.0 | |
| Unknown | 0.5 | 44.3 | 23.6 | 12.3 | 19.8 | |
| Service Connected Disability | 65.4 | 26.9 | 25.7 | 21.4 | 26.0 | < .00001 |
| CCI, mean (SD) | 0.40 (0.98) | 0.36 (0.95) | 0.39 (0.98) | 0.40 (0.96) | 0.43 (1.00) | < .01 |
| CCI = 0 | 78.0 | 28.1 | 26.3 | 21.3 | 24.3 | < .001 |
| CCI ≥ 1 | 22.0 | 25.2 | 25.9 | 21.9 | 27.0 | |
| Pharmaceutical Use d | ||||||
| Opioid Prescription | 13.3 | 28.3 | 26.3 | 19.1 | 26.4 | .010 |
| Tramadol Prescription | 8.0 | 27.8 | 26.9 | 19.5 | 25.8 | .238 |
| Medical Comorbidities | ||||||
| PTSD | 20.1 | 27.3 | 26.5 | 21.5 | 24.7 | .967 |
| Mild Depression | 21.3 | 26.2 | 25.9 | 20.5 | 27.5 | < .0001 |
| Major Depression | 7.9 | 24.7 | 26.1 | 22.8 | 26.4 | .051 |
| Schizophrenia | 0.5 | 27.9 | 29.8 | 15.4 | 26.9 | .477 |
| Bipolar | 4.4 | 24.7 | 28.8 | 21.4 | 25.1 | .199 |
| TBI | 4.7 | 29.4 | 28.2 | 21.9 | 20.6 | .017 |
| Alcohol or Substance Use Disorder | 10.7 | 27.1 | 27.4 | 21.0 | 24.6 | .663 |
BMI Body mass index; IQR Interquartile range; NRS Numerical rating scale; CCI Charlson Comorbidity Index; PTSD Post-traumatic stress disorder; TBI Traumatic brain injury; Significance at α = 0.05; a 3621 other/missing; b 685 other/missing; c 278 missing; d Prescription within 30 days of MSD Cohort entry