Table 3.
ORs for Predicting Assignment to a Primary Care Provider Who Is an NP or PA, Compared With Physician Among Facilities With Physician, NP, and PA Provider Types.
| Effect and level | OR for assignment to NP | 95% CI for assignment to NP | P value for assignment to NP | OR for assignment to PA | 95% CI for assignment to PA | P value for assignment to PA |
|---|---|---|---|---|---|---|
| Patient-level factors | ||||||
| Male | 0.42 | 0.39-0.45 | <.001 | 1.28 | 1.14-1.43 | <.001 |
| Age group | ||||||
| Less than 40 | Reference | Reference | Reference | Reference | ||
| 40 to less than 65 | 0.74 | 0.63-0.85 | <.001 | 0.75 | 0.63-0.88 | <.001 |
| 65 to less than 80 | 0.72 | 0.62-0.83 | <.001 | 0.73 | 0.62-0.87 | <.001 |
| 80 and above | 0.67 | 0.57-0.79 | <.001 | 0.67 | 0.56-0.79 | <.001 |
| Race | ||||||
| White | Reference | Reference | Reference | Reference | ||
| American Indian | 1.00 | 0.84-1.18 | .956 | 1.00 | 0.82-1.21 | .962 |
| Asian | 1.04 | 0.83-1.30 | .730 | 1.05 | 0.77-1.42 | .768 |
| Black | 1.01 | 0.96-1.06 | .705 | 1.09 | 1.04-1.15 | <.001 |
| Native Hawaiian | 1.00 | 0.85-1.18 | .979 | 0.81 | 0.67-0.98 | .033 |
| Unknown or Missing | 1.02 | 0.96-1.09 | .431 | 1.02 | 0.95-1.09 | .620 |
| Hispanic | 0.95 | 0.87-1.04 | .273 | 1.03 | 0.95-1.13 | .449 |
| Marital status | ||||||
| Currently married | Reference | Reference | Reference | Reference | ||
| Never married | 1.02 | 0.96-1.07 | .539 | 1.02 | 0.96-1.08 | .447 |
| Previously married | 1.04 | 1.00-1.07 | .068 | 1.04 | 1.00-1.08 | .048 |
| Unknown marital status | 1.49 | 1.13-1.97 | .005 | 1.23 | 0.86-1.76 | .254 |
| Homeless at any time during year | 1.16 | 1.04-1.29 | .007 | 1.09 | 0.95-1.24 | .225 |
| Copay status | ||||||
| Must pay copay | Reference | Reference | Reference | Reference | ||
| No copay due to disability | 0.94 | 0.90-0.98 | .008 | 0.94 | 0.90-0.99 | .013 |
| No copay due to low income | 0.96 | 0.91-1.01 | .130 | 0.96 | 0.91-1.01 | .093 |
| Unknown copay status | 1.04 | 0.89-1.21 | .600 | 0.92 | 0.77-1.10 | .356 |
| Mental health diagnoses | ||||||
| Mood disorder | 1.01 | 0.96-1.05 | .785 | 0.99 | 0.95-1.04 | .747 |
| PTSD | 1.05 | 1.00-1.10 | .076 | 1.02 | 0.96-1.07 | .538 |
| Dementia | 0.89 | 0.80-0.98 | .021 | 0.99 | 0.89-1.10 | .808 |
| Substance abuse | 1.11 | 1.04-1.18 | .001 | 1.01 | 0.94-1.08 | .827 |
| Other mental health diagnosis | 1.19 | 1.11-1.28 | <.001 | 1.09 | 1.01-1.17 | .035 |
| DCG score category | ||||||
| Less than or equal to 0.5 | Reference | Reference | Reference | Reference | ||
| Greater than 0.5 to 1 | 1.00 | 0.95-1.04 | .880 | 0.96 | 0.92-1.01 | .110 |
| Greater than 1 to 1.5 | 0.95 | 0.91-1.00 | .060 | 0.95 | 0.90-1.00 | .041 |
| Greater than 1.5 to 2 | 0.86 | 0.81-0.92 | <.001 | 0.92 | 0.86-0.99 | .022 |
| Greater than 2 | 0.83 | 0.79-0.88 | <.001 | 0.85 | 0.80-0.89 | <.001 |
| Distance from VHA primary care clinic | ||||||
| Less than 5 miles | Reference | Reference | Reference | Reference | ||
| 5 to less than 25 miles | 1.00 | 0.96-1.04 | .982 | 1.04 | 0.99-1.09 | .082 |
| 25 to less than 50 miles | 1.04 | 0.99-1.10 | .121 | 1.09 | 1.03-1.15 | .003 |
| 50 miles or greater | 1.00 | 0.94-1.07 | .982 | 1.15 | 1.07-1.23 | <.001 |
| Missing | 1.72 | 1.40-2.11 | <.001 | 1.37 | 1.05-1.79 | .021 |
| Facility-level factors | ||||||
| Endocrinology referral capacitya | 0.87 | 0.68-1.12 | .284 | 0.80 | 0.62-1.04 | .097 |
| Percent of providers in the primary care clinic who are PAs | ||||||
| Lowest tertile | Reference | Reference | Reference | Reference | ||
| Middle tertile | 1.05 | 0.79-1.40 | .724 | 4.40 | 3.29-5.89 | <.001 |
| Highest tertile | 1.63 | 1.20-2.22 | .002 | 18.19 | 13.32-24.84 | <.001 |
| Percent of providers in the primary care clinic who are NPs | ||||||
| Lowest tertile | Reference | Reference | Reference | Reference | ||
| Middle tertile | 6.35 | 4.65-8.66 | <.001 | 1.14 | 0.84-1.55 | .413 |
| Highest tertile | 21.54 | 15.80-29.38 | <.001 | 1.71 | 1.26-2.33 | <.001 |
| Rural-urban commuting area status | ||||||
| Metropolitan area core | Reference | Reference | Reference | Reference | ||
| Metropolitan area core—remaining levels | 0.97 | 0.63-1.48 | .884 | 0.90 | 0.59-1.37 | .620 |
| Micropolitan area core | 1.07 | 0.69-1.65 | .773 | 1.10 | 0.71-1.70 | .662 |
| Small town or rural | 1.32 | 0.60-2.88 | .492 | 1.47 | 0.66-3.29 | .345 |
| State-level factors | ||||||
| Region | ||||||
| Northeast | Reference | Reference | Reference | Reference | ||
| West | 0.72 | 0.46-1.11 | .137 | 0.60 | 0.38-0.93 | .024 |
| Midwest | 0.69 | 0.48-0.98 | .039 | 0.79 | 0.55-1.13 | .193 |
| South | 0.86 | 0.60-1.22 | .389 | 0.88 | 0.62-1.26 | .483 |
| Percent of primary care physicians who work with NPs/PAs | ||||||
| Lowest tertile | Reference | Reference | Reference | Reference | ||
| Middle tertile | 1.07 | 0.76-1.53 | .687 | 0.84 | 0.59-1.19 | .330 |
| Highest tertile | 1.35 | 0.91-2.00 | .139 | 1.03 | 0.69-1.54 | .869 |
| Nurse practitioner scope of practice regulations | ||||||
| Lowest tertile | Reference | Reference | Reference | Reference | ||
| Moderately restrictive | 0.75 | 0.45-1.26 | .276 | 1.05 | 0.63-1.76 | .852 |
| Most restrictive | 1.12 | 0.74-1.71 | .592 | 0.90 | 0.59-1.38 | .623 |
| Physician assistant scope of practice regulations | ||||||
| Lowest tertile | Reference | Reference | Reference | Reference | ||
| Moderately restrictive | 1.20 | 0.78-1.83 | .402 | 1.13 | 0.74-1.74 | .561 |
| Most restrictive | 1.15 | 0.79-1.66 | .460 | 1.15 | 0.79-1.67 | .457 |
Note. Data for patient-level variables are from the VA electronic health record files. Other data sources are described in the “Methods” section. PCP is assigned as the physician, NP, or PA seen most during FY 2012 and 2013. OR = odds ratio; NP = nurse practitioner; CI = confidence interval; PA = physician assistant; PTSD = posttraumatic stress disorder; DCG = Diagnostic Cost Group; VHA = Veterans Health Administration; PCP = primary care provider; FY = fiscal year.
a
Endocrinology referral capacity is defined as either present (endocrinology or other diabetes mellitus specialty clinics provided 500 or more visits to cohort patients in FY 2012) or absent (fewer than 500 visits to cohort patients).