Each CaReNet practice collected data on a total of 400 patient visits in 1-week cycles (100 patients per cycle), quarterly, for 1 year. We used the typical NAMCS protocol of collecting data on every second patient presenting for medical care during the study period.14 The anonymous visit survey forms were coded using standard NAMCS nomenclature. Only patients aged between 13 years and 65 years were included in this analysis because there are almost no uninsured people older than 65 years. To identify patients with private insurance, the options “Private/commercial” and “HMO/other prepaid” were combined (hereafter referred to as “Private/HMO”).
For the present study, we examined the impact of patient insurance on 2 primary outcomes: (1) patient smoking status, and (2) whether smokers received smoking cessation counseling. Each provider coded smoking status as “Yes,” “No,” or “Unknown.” Only patients with a known smoking status (90% of sample) were included in the present analysis. For those patients coded as smokers, we determined whether providers checked the “Smoking Cessation” box.
Analysis
To examine the association between insurance group and study outcomes, we used chi-square tests to determine whether insurance group and other patient demographics (sex, age, ethnicity, and race) were reliably associated with smoking status and cessation counseling. Next, for each primary outcome, we conducted multivariate analyses to examine the effect of patient insurance, while controlling for other important demographic factors (ie, those with P values 0.20 in univariate analyses,15 as well as additional factors that may account for variability in this relationship. These factors included duration of visit, whether the patient had been seen before in the practice, and whether the patient had at least 1 of the chronic conditions listed on the NAMCS form (hypertension, depression, obesity, or hypercholesterolemia). Because initial random effects analyses revealed no significant practice site effects on the frequency of tobacco use and cessation counseling, all analyses include patient-level data.
The Colorado Multiple Institutional Review Board approved our study design.
Results
Description of sample
CaReNet providers completed NAMCS forms on 2773 patient encounters of 2800 eligible visits (99% completion rate). For this study, of the 2773 encounters, 1443 remained after excluding patients younger than 13 or older than 65 years, and those with sources of payment other than Medicaid, Uninsured, or Private/HMO. As shown in (Table 1), CaReNet patients in the present study were demographically diverse, with a high percentage who were Hispanic (26%), female (74%), or low-income (39% uninsured, 22% Medicaid).
TABLE 1
DEMOGRAPHIC CHARACTERISTICS OF CARENET STUDY SAMPLE
| Characteristics | N | %* |
|---|---|---|
| Sex | ||
| Female | 1063 | 74 |
| Male | 380 | 26 |
| Age | ||
| 13-17 | 75 | 5 |
| 18-44 | 886 | 61 |
| 45-64 | 482 | 33 |
| Ethnicity † | ||
| Hispanic | 369 | 26 |
| Non-Hispanic | 1068 | 74 |
| Race ‡† | ||
| Asian-Pacific Islander | 10 | < 1 |
| Black | 104 | 7 |
| Indian-Eskimo-Aleut | 32 | 2 |
| White | 1282 | 89 |
| Insurance Status | ||
| Uninsured | 560 | 39 |
| Medicaid | 311 | 22 |
| Private/HMO | 572 | 40 |
| *Percentages may not add to 100 because of rounding. | ||
| † Ethnic background is missing for 6 patients. | ||
| ‡ Race is missing for 15 patients. | ||
| § For all remaining analyses, we have re-coded race into “white” or “non-white.” | ||
Univariate and multivariate analysis of smoking
A total of 351 patients in the study sample (24%) were identified as smokers. As expected, smoking was significantly more prevalent in the Medicaid and uninsured groups (Table W1*).
(Table 2) presents multivariate logistic regression results showing the significant relationship between insurance and smoking status after controlling for other important demographic and practice variables. Uninsured patients had similar rates of smoking as those with Medicaid; however, smoking among Private/HMO–insured patients was approximately half as frequent as among the uninsured.
In addition to patient insurance, ethnicity and clinical factors predicted whether patients smoked. Non-Hispanic patients were more than twice as likely to be identified as smokers compared with Hispanic patients (P <.001). Also, patients who were new to the practice or who had at least one chronic condition were significantly more likely to be identified as smokers (P = .011 and P = .001, respectively).
Table 2
LOGISTIC REGRESSION RESULTS: RELATIONSHIP OF PATIENT FACTORS WITH LIKELIHOOD OF SMOKING
| Patient Factor | Odds Ratio for Smoking (95% CI) | P |
|---|---|---|
| Insurance | ||
| Uninsured* | 1.00. | |
| Medicaid | 1.01 (0.73 – 1.4) | .937 |
| Private/HMO | 0.55 (0.41 – 0.73) | < .001 |
| Sex | ||
| Female* | 1.00 | |
| Male | 1.22 (0.92 – 1.6) | .164 |
| Ethnicity | ||
| Hispanic* | 1.00 | |
| Non-Hispanic | 2.1 (1.5 – 3.0) | < .001 |
| Patient Seen Before | ||
| Yes* | 1.00 | |
| No | 1.6 (1.1 – 2.3) | .011 |
| Duration of Visit | 1.00 | .990 |
| Chronic Disease | ||
| None* | 1.00 | |
| One or more | 1.6 (1.2 – 2.0) | .001 |
| CI denotes confidence interval. | ||
| *Reference group. | ||
Univeriate and multivariate analysis of cessation advice or counseling
The second primary analysis examined whether insurance is associated with how often smokers are counseled during visits. Out of 351 smokers, 129 (37%) received tobacco counseling during the medical encounter. Private/HMO insurance and duration of visit were the only factors univariately associated with whether a smoker received counseling (Table W2*).
Multivariate results indicate that patient insurance remained the only significant variable after controlling for other factors that might explain whether smokers received counseling. Smokers with Medicaid were more than twice as likely, and Private/HMO–insured smokers were more than 3 times as likely as uninsured patients (P <.001) to receive smoking cessation counseling (Table 3).