National Patterns in the Treatment of Smokers by Physicians FREE

CIGARETTE SMOKING is the single most important cause of death and disability in the United States.¹ Because an estimated 70% of smokers visit a physician each year, physicians have the opportunity to promote smoking cessation.² Brief physician counseling and the use of nicotine replacement therapy (NRT) have been shown to increase the smoking cessation rates of patients.^3- 5 The likelihood that a physician will counsel a smoker is increased by routine identification of a patient's smoking status in the medical record.^6- 7

This evidence has led several professional and government organizations to make recommendations to physicians about the treatment of smokers.^8- 12 In 1996, the Agency for Health Care Policy and Research released an evidence-based clinical guideline that directed primary care physicians to identify a patient's smoking status at every visit, counsel smokers at every visit, and offer NRT to patients planning to quit.¹⁰ National health promotion objectives for the year 2000 call for increasing to 75% the proportion of primary care providers who routinely advise cessation and provide assistance to their patients who smoke.¹¹ The rate of physicians' advice to smokers is now a quality measure for US health plans.¹²

Despite this consensus, it is unclear how frequently physicians identify and treat smokers. Surveys have produced conflicting results depending on whether information is obtained from patients or physicians. Seventy percent to 98% of surveyed physicians report that they routinely ask their patients about their smoking status or record the patient's smoking status on the chart,^13- 16 and 46% to 77% of physicians report that they routinely counsel their patients to quit.^{13,15,17- 20} In contrast, only half the smokers report having ever been advised by their physician to quit.^2,21- 24 This discrepancy is more than likely attributable to recall bias. Physicians may overestimate how often they address smoking while smokers may underestimate how often they are counseled. The National Ambulatory Medical Care Survey (NAMCS) is an annual office-based survey that US physicians complete during each patient's visit. It provides a more accurate assessment of physicians' actual practice than previous surveys.²⁵ We analyzed NAMCS data collected from 1991 to 1995 to assess recent national patterns in the routine ambulatory care of smokers.

The NAMCS is an ongoing annual survey of US office-based physicians conducted by the National Center for Health Statistics (NCHS).²⁵ Doctors of medicine and osteopathic medicine are selected by stratified random sampling from the American Medical Association and the American Osteopathic Association listings of all practicing physicians in the United States. The unit of analysis is the patient visit. Each participating physician completes a 1-page encounter form after each ambulatory care visit during a randomly assigned week. Outpatient care provided in hospital settings, by telephone, or by nonphysician providers is excluded. Physicians record information about patient demographics, smoking status, expected source of payment, reasons for the visit, diagnoses, counseling and education provided, and current medications. Missing data are limited to approximately 5% of patient visits.²⁵ The cross-sectional nature of NAMCS permits patterns in physician practices to be followed over time but does not allow individual physicians or patients to be followed longitudinally.

The NCHS uses a complex 3-stage sampling design that has previously been described.²⁶ To produce unbiased national estimates, each patient visit is assigned an inflation factor called the patient visit weight that is based on the probability of selection, the differences in response rates, and the specialty distributions. All statistical estimates presented in the results of this study are weighted to reflect national estimates. The NCHS provides relative SEs for estimates to gauge the reliability of an estimate for an individual year. An estimate with a relative SE greater than 30% could be unreliable.²⁵

We analyzed data collected from 1991, when smoking status was first included on the survey, to 1995, the most recent year available. Physician response rates varied between 70% and 73% for the 5 years.²⁵ All visits by patients aged 18 years or older were included. We examined changes in physician practices from 1991 to 1995 and then combined data from the 1994 and 1995 surveys to describe recent physician practices. We examined 3 outcomes: (1) identification of a patient's smoking status, (2) provision of smoking counseling, and (3) reporting of NRT use. Physicians identified a patient's smoking status by answering the question, "Does patient smoke cigarettes?" Smoking status was categorized as "known" if the answer was yes or no; otherwise, smoking status was "unknown." Physicians recorded smoking counseling by checking the appropriate box under "Counseling/Education." Nicotine replacement therapy that included both nicotine gum and patches was recorded on the survey form under "Medications." Nicotine replacement products were available only by prescription during the survey years. All adult patient visits were included in the analysis of smoking status. Analyses of smoking counseling and NRT were restricted to visits by patients identified as smokers.

Independent predictors of smoking status identification, smoking counseling, and NRT use were determined with weighted multiple logistic regression.²⁷ Covariates included in the models for all 3 outcomes were survey year, patient demographics (age, sex, and race), geographic region, expected payment source for the visit, diagnoses and reasons for visit, physician specialty, and counseling for other cardiovascular risk factors (cholesterol, weight reduction, and exercise) provided during the visit. Because the 3-stage sampling design could not be accounted for in the logistic regression models, statistical significance was defined conservatively as a 2-tailed P value at a level of ≤.01. To analyze time trends, each year was included in the multivariate models as a categorical variable using the year 1993 as the reference variable.

Four categories of diagnoses were assessed as predictor variables because of their association with adverse outcomes from continued smoking. They were cardiovascular disease, chronic pulmonary disease, diabetes, and pregnancy. Each category represented a combination of reason for visit codes created by the NCHS for the NAMCS²⁵ and the International Classification of Diseases, 9th Revision, diagnosis codes.²⁸ The cardiovascular disease category included hypertension, coronary artery disease, cerebrovascular disease, and peripheral vascular disease. Chronic pulmonary disease included chronic bronchitis, emphysema, and asthma. A fifth category, general medical examination, was included because we hypothesized that a physician would be more likely to identify smoking status and to counsel smokers during this type of visit. All diagnosis categories were created as binary variables, eg, cardiovascular disease vs no cardiovascular disease; therefore, each visit could be included in more than 1 diagnosis category. Physicians were categorized as primary care (general internists, family practitioners, and generalists) or specialists (all other specialties). Expected payment source for the visit was divided into 5 categories: health maintenance organization, private insurance, Medicaid, Medicare, and other insurance.

To further explore the association between physician intervention and the specific problem addressed during the visit, we calculated the rate of smoking counseling for the most common primary diagnoses of smokers visiting primary care physicians. A primary diagnosis is the diagnosis associated with the patient's primary reason for making the visit and was determined by using the first diagnosis written on the survey by the physician. We then grouped clinically related primary diagnoses using Schneeweiss diagnosis clusters.²⁹

Data were available on 145716 adult patient visits to 3254 physicians from 1991 through 1995. Smoking status was identified at 95540 visits, which represented 66% of all visits. Patients were identified as smokers at 17632 visits from 1991 through 1995, which represented 12% of all visits and 18% of visits where smoking status was known. The proportion of visits in which a patient's smoking status was identified did not change significantly between 1991 and 1994 but fell in 1995 from 67% of all visits in 1994 to 61% in 1995 (P<.001). The proportion of visits by patients identified as smokers did not change significantly from 1991 to 1995 (Figure 1). (All comparisons presented in the "Results" section are adjusted; see "Methods.")

Smoking counseling was provided at 3302 smokers' visits, and NRT was reported at 161 smokers' visits, which represented 22% and 1%, respectively, of visits by smokers from 1991 through 1995. Smoking counseling increased from 16% of smokers' visits in 1991 to a peak of 29% in 1993 (P<.001) and then declined to 21% of smokers' visits in 1995 (P<.001) (Figure 2, top). Primary care physicians counseled smokers at a significantly higher rate than specialists in each year except 1991 (1992-1995, P<.001). Between 1991 and 1993, counseling by primary care physicians increased from 20% to 38% of smokers' visits (P<.001), while counseling by specialists only rose from 12% to 19% of visits (P<.001). Between 1993 and 1995, counseling rates fell for both types of practitioners from 38% to 29% of smokers' visits to primary care physicians (P<.001) and from 19% to 14% of smokers' visits to specialists (P<.001).

The NRT use was reported infrequently. We caution that these estimates may be unreliable because the relative SEs were greater than 30% (see "Methods"). The NRT use increased from 0.4% of smokers' visits in 1991 to 2.2% of smokers' visits in 1993 (P<.001) with a subsequent decrease in 1995 to 1.3% (P=.007) (Figure 2, bottom). Primary care physicians reported NRT use significantly more often than specialists in 1993 through 1995 (1993, P=.008; 1994-1995, P<.001). Between 1991 and 1993 NRT use increased among both primary care physicians (0.6% to 3.0% of smokers' visits, P<.001) and specialists (0.2% to 1.3% of smokers' visits, P<.001). The NRT use decreased significantly among specialists between 1993 and 1995 (1.3% to 0.4%, P<.001) but not among primary care physicians (3.0% to 2.4%, P=.3). Nicotine gum accounted for all NRT reported in 1991 and 1992 while nicotine patches accounted for more than 90% of NRT reported in 1993 through 1995. Physicians provided smoking counseling at 82% of visits at which NRT was reported.

Table 1 displays factors independently associated with physicians' identification of a patient's smoking status and provision of smoking counseling at visits in 1994 and 1995. Primary care physicians were more likely than specialists to identify a patient's smoking status and were twice as likely to counsel about smoking. All physicians were at least 1.5 times more likely to identify a patient's smoking status and counsel for smoking at visits by patients with cardiovascular disease, chronic pulmonary disease, or pregnancy. Smoking counseling was more likely to occur at a general medical examination than at other types of visits (37% vs 22% of visits, P<.001), and at a first visit compared with a return visit (25% vs 23%, P=.002). Physicians were no more likely to identify a patient's smoking status at a general medical examination or at a new patient visit. Counseling about smoking was more likely to occur at visits that also included counseling for other cardiovascular risk factors. Elderly patients were less likely than younger patients to have smoking status identified and to be counseled about smoking. Men and nonwhites were less likely than women and whites to have smoking status identified but were no less likely to be counseled for smoking. A patient's insurance status had little effect on the likelihood that a smoker would be identified or counseled.

Figure 3 displays the rate of smoking counseling for the most common primary diagnoses of smokers visiting primary care physicians in 1994 and 1995. There is wide variability in physician counseling depending on the patient's primary diagnosis for the visit. Physicians were most likely (≥35% of visits) to counsel about smoking at visits for acute and chronic respiratory disorders, cardiovascular disorders, alcohol and drug abuse, peptic diseases, and diabetes. These diagnoses are all caused or complicated by tobacco use. In contrast, physicians were least likely (≤20% of visits) to counsel smokers who were seen for musculoskeletal disorders, nonrespiratory infections, and lacerations and contusions, which are all conditions unrelated to smoking.

This study examined national patterns in physicians' treatment of smokers in office practice during the first half of this decade. It is distinguished from previous work in that it analyzed data collected over 5 years from a large nationally representative sample of US physicians who reported their actions at the time of a patient visit rather than summarizing their practice patterns retrospectively as most previous studies have done. This study demonstrates that physicians' practices clearly fall short of national health goals for the year 2000, current practice guidelines, and new performance standards for health plans.^10- 12 Primary care physicians did better than specialists but still fell far short of these goals. However, more importantly, the study failed to find evidence of sustained improvement in physicians' practice during the early 1990s. Physicians' rates of providing smoking counseling and prescribing NRT increased to a peak in 1993 but decreased thereafter, and the rate at which physicians identified a patient's smoking status did not improve over the 5-year study period.

Physicians reported counseling about smoking at only 23% of office visits by patients whom they identified as smokers. As expected, counseling occurred more often at a general medical examination than at a visit for a specific problem, but even so, physicians addressed smoking at only 37% of smokers' general medical examinations. These smoking counseling rates indicate that physicians' treatment of smoking is even further from recommended practice standards than previous surveys have suggested.^17- 18,20 Previous physician surveys are more subject to recall bias than the NAMCS because physicians retrospectively summarize their practice patterns, and their reports may reflect their intentions rather than their actual practices. While most physicians believe that smoking is an important health behavior and rank counseling about smoking as the most important preventive service that they can provide,^14,16,20 they also report that counseling is frustrating and time-consuming.²⁰

Our analysis documents a nearly 6-fold variation in physicians' smoking counseling practices according to the reason for the patient's visit. Physicians were more likely to address smoking behavior if the patient's presenting problem was caused or exacerbated by smoking or if the patient had a chronic smoking-related illness. This is consistent with previous surveys of patients and physicians.^{13,17,21- 22} Recent national guidelines recommended that smoking should be addressed even when patients are seen for problems unrelated to smoking.¹⁰ This clearly was not included in the physician's practice in the early 1990s.

Our results represent a first nationwide look at physicians' use of NRT at a time when it was available only by prescription, although conclusions are limited by the small numbers of visits at which the therapy was used. The low prevalence of NRT use is most likely due to the cross-sectional nature of the survey, the low prevalence of smokers who are ready to quit at any given visit, and the short-term use of the medication. The NRT use rose to a peak in 1993, the year after the transdermal nicotine patch was introduced to the US market, and subsequently declined. This pattern resembles the US sales of the patch, whose annual sales rose rapidly after its introduction in 1992 to $600 million and subsequently declined to $250 million.³⁰

It is not surprising that the introduction of the nicotine patch led to an increase in physicians' use of nicotine replacement products. However, our data suggest that the introduction of the patch also contributed to a transient increase in physician counseling about smoking even at visits where NRT was not prescribed. Although many factors influence physician behavior, we are unaware of any other temporal change that could explain the transient peak in physicians' smoking counseling in 1993. The nicotine patch may have influenced physician counseling in 2 ways. First, the patch provided physicians with a new therapeutic option that may have encouraged them to discuss smoking cessation with patients. Second, the patch was directly marketed to consumers and attracted considerable media attention, creating consumer awareness and demand for a product available only from physicians.^31- 33 Only 25% of patients who were filling a nicotine patch prescription in 1994 stated that they learned about the patch from their physicians,³¹ and between 60% and 80% of patients who used the patch in 1992 reported that they requested the patch from their physician.^32- 33 Consumer demand for the product may have increased physician smoking counseling rates even when a prescription for nicotine replacement was not provided.

Identifying a patient's smoking status is a necessary first step because treatment cannot be provided if the physician does not recognize that the patient is a smoker.^8- 10 While there are no previous national estimates of how frequently physicians assess patients' smoking status, 70% to 92% of physicians surveyed in the 1980s reported that they determined the smoking status of all their patients,^13- 15 and 98% of Massachusetts physicians reported in 1994 that they "regularly gathered information about smoking."¹⁶ Our data indicate that these surveys overestimate actual physician practices and that physicians were unaware of a patient's smoking status at one third of all visits. This proportion did not change when the analysis was limited to new patient visits or visits for a general medical examination when assessment of smoking behavior might be more likely to occur. Physicians miss the opportunity to counsel a substantial portion of their patients who smoke because they are unaware of their smoking status, which may partially explain the discrepancy between patient and physician reporting of smoking counseling in previous surveys.

The visit-based nature of the NAMCS is a strength of this study but also presents limitations. Our estimates reflect only the probability of being counseled at a visit not the probability of an individual patient being counseled over a given period, such as a year. Patients who visit physicians frequently might be less likely to be treated for smoking at an individual visit but more likely to be treated over a year, as a recent survey of patients in 4 midwestern states observed.³⁴ Our results may overestimate the amount of physician intervention beyond advice to quit because some physicians may have interpreted "counseling" to only mean giving advice to quit. The NAMCS may have some recall bias because physicians fill out the survey after a patient encounter, but this possibility is much less than in previous physician surveys. The prevalence of smokers among visits where smoking status was identified was 18%, which is somewhat lower than the US adult smoking prevalence of 25%. ³⁵ It is likely that some smokers did not truthfully report their smoking status to their physician. There may be more error in the estimates of counseling and NRT use than in the estimates of smoking status identification, because estimates of smoking counseling and NRT use were limited to visits by patients identified as smokers, and these visits may not be representative of visits by all smokers. Finally, in the logistic regression models that estimated year-to-year trends and aggregated yearly data, we were not able to account for correlations in time between estimates. The effect of these correlations on statistical inference is to increase the SEs but not to affect the point estimates of the relative odds.

In conclusion, in the first half of the 1990s physicians made little progress in the treatment of smokers. This finding highlights the importance of efforts to institutionalize the identification of smoking status into office practice by using system-wide interventions or assessing smoking status as if it were a vital sign.^6- 7,10 Our observation of a transient increase in smoking counseling in 1993, the year following the introduction of the nicotine patch, was unexpected and suggests that the introduction of pharmacotherapies for smoking cessation may influence not only physicians' prescribing practices but also their willingness to counsel smokers. It will be important to determine the effects of more recent events, such as the shift of nicotine gum and patches to nonprescription status in 1996 and the introduction of new prescription drugs for smoking cessation in 1997, on physicians' behavior.