Table 1.

Patient Characteristics

Racial Group
CharacteristicAll Patients (N=1,612)Black Patients (n=1,001)xWhite Patients (n=611)P Valuea
a χ2 test for categorical variables; t test for continuous variables.
b Median annual household income in patient’s ZIP code.
c Based on physician International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) coding.
d Based on physician ICD-9-CM coding; patients may have multiple pain diagnoses.
e Lower = at least one 6-month period without a visit and bottom quartile in office visit frequency; Higher = at least one visit in each 6-month period and highest quartile in office visit frequency; Intermediate = remaining patients.
Outcome variables
Urine drug testing, any, No. (%)129 (8.0)104 (10.4)25 (4.1)<.001
Regular office visits, No. (%)803 (49.8)565 (56.4)238 (39.0)<.001
Restricted early refills, No. (%)1,235 (76.6)795 (79.4)440 (72.0)<.001
Demographics
Age, mean (SD), years54.1 (15.5)53.6 (14.9)54.7 (16.4).17
Women, No. (%)1,070 (66.4)708 (70.7)362 (59.3)<.001
Household income, No. (%)b<.001
    <$25,000407 (25.3)380 (38.0)27 (4.4)
    $25,000–$34,999546 (33.9)484 (48.4)62 (10.2)
    $35,000–$69,999544 (33.8)129 (12.9)415 (67.9)
    ≥$70,000115 (7.1)8 (0.8)107 (17.5)
Substance abusec
Problem substance use, No. (%)174 (10.8)130 (13.0)44 (7.2)<.001
Tobacco use, No. (%)259 (16.1)187 (18.7)72 (11.8)<.001
Mental and physical health
Mental health disorder,c No. (%)780 (48.4)478 (47.8)302 (49.3).51
Pain diagnosis,d No. (%)
    Osteoarthritis693 (43.0)482 (48.2)211 (34.5)<.001
    Rheumatoid arthritis130 (8.1)83 (8.3)47 (7.7).66
    Lumbago830 (51.5)536 (53.6)294 (48.1).03
    Cervical/thoracic spine pain390 (24.2)234 (23.4)156 (25.5).33
    Sciatica375 (23.3)225 (22.5)150 (24.6).34
    Neuropathic pain427 (26.5)279 (27.9)148 (24.2).11
    Fibromyalgia260 (16.1)160 (16.0)100 (16.4).84
Medical comorbidities,c No. (%)<.001
    None250 (15.5)110 (11.0)140 (22.9)
    1412 (25.6)224 (22.4)188 (30.8)
    2385 (23.9)238 (23.8)147 (24.1)
    ≥3565 (35.1)429 (42.9)136 (22.3)
Health care factors
Duration of long-term opioid treatment, mean (SD), weeks100.0 (62.9)101.9 (64.4)96.8 (60.4).11
Appointment attendance rate, median (SD)0.65 (0.15)0.62 (0.15)0.69 (0.14)<.001
Primary care use,e No. (%).002
    Lower256 (15.9)135 (13.5)121 (19.8)
    Intermediate1,008 (62.5)634 (63.3)374 (61.2)
    Higher348 (21.6)232 (23.2)116 (19.0)