Randomization resulted in groups with similar baseline characteristics (). In addition to smoking, 427 participants (57%) had at least one other major risk factor for cardiovascular disease. Participants reported seeing their physician a median of 3.5 times in the twelve months prior to the study. Participants smoked on average 24 cigarettes per day; 30.4% were at the preparation stage of quitting, 60.9% at the contemplation stage, and 8.7% at the precontemplation stage.
Baseline Characteristics of Study Participants
Prior to the 24 month follow-up, 24 participants died or were incarcerated. Of the 750 participants, loss to follow-up due to non-response varied by treatment group () with 22.0% of the pharmacotherapy management group, 31.3% of the moderate-intensity disease management group, and 31.1% of the high-intensity disease management group lost to follow-up during one or more of the assessment periods (p = 0.03).
Utilization of counseling
During the course of the 24 month intervention, high-intensity disease management participants completed an average of 8.2 counseling calls (range 0 –24) and moderate-intensity disease management participants completed an average of 3.6 calls (range 0 – 7). Engagement in counseling declined during the course of the intervention with 90.9%, 67.9%, 57.3%, and 54.3% of high-intensity disease management participants participating in at least one counseling session, and 90.0%, 68.2%, 60.3%, and 59.2% of moderate-intensity disease management participants participating in at least one counseling session during the 1st, 2nd, 3rd, and 4th cycles of treatment, respectively, (). The average number of calls completed was 3.2, 1.8, 1.6, and 1.7 for high-intensity disease management recipients and 1.3, 0.9, 0.7, and 0.7 for moderate-intensity recipients during the 1st, 2nd, 3rd, and 4th cycles of treatment, respectively.
Number of Counseling Calls Completed Among Recipients of Moderate-Intensity Disease Management (MDM), or High-Intensity Disease Management (HDM)
Utilization of pharmacotherapy
We identified a treatment-by-time interaction in utilization of pharmacotherapy (likelihood ratio chi-square tests df=6, p < 0.01). Thus, comparisons between treatment groups in use of pharmacotherapy were derived at each survey period. These results () found differences in pharmacotherapy uptake in the pooled disease management arms compared to pharmacotherapy management, with an increase in uptake during the first 6-month period (OR,1.53 [95% CI, 1.10 to 2.13]), but lower uptake in the disease management arms during the following 6-month period (OR, 0.71 [95% CI, 0.51 to 0.99]). Requests for pharmacotherapy declined following the first 6-month study period. Among all participants, 63.8%, 40.9%, 23.9%, and 24.7% requested pharmacotherapy during the 1st, 2nd, 3rd, and 4th cycles of treatment, respectively. By the conclusion of the study, 23%, 33%, 23%, 12%, and 9% of participants had requested a total of 0, 1, 2, 3, or 4 cycles of pharmacotherapy, respectively. Overall, 41.1% of pharmacotherapy treatment cycles utilized bupropion and 58.9% utilized the nicotine patch with no difference in choice of pharmacotherapy between the treatment groups.
Utilization of Pharmacotherapy (nicotine patch or bupropion) by Treatment Period Among Recipients of Pharmacotherapy Management (PM), Moderate-Intensity Disease Management (MDM), or High-Intensity Disease Management (HDM)
Support from health care providers
In the three treatment groups combined, 635 (84.7%) of participants reported one or more office visits with their physician with a median of 5 visits over the course of the two year study. Of participants that saw a physician during any given treatment cycle, the proportion reporting that they discussed smoking cessation with their physician ranged from 37.5 – 59.5% () and did not vary between treatment arms (OR, 1.03 for high-intensity versus moderate-intensity disease management [95% CI, 0.75 to 1.41] and OR, 0.92 for the pooled disease management groups versus pharmacotherapy management alone [95% CI, 0.70 to 1.19]) ().
Frequency of Patient/Physician Smoking Related Discussions by Treatment Cycle Among Recipients of Pharmacotherapy Management (PM), Moderate-Intensity Disease Management (MDM) and High-Intensity Disease Management*
Throughout the study, smokers moved through different transitional states of smoking status (). In our primary, 24 month analysis, the7-day, point prevalence self-reported abstinence was 27.9% and 23.5% in the high-intensity and moderate-intensity disease management groups, respectively (OR, 1.33 [95% CI, 0.88 to 2.02]) (missing = smoking) (). The cessation rate in these disease management groups combined was similar to the 23.0% self-reported cessation rate in the pharmacotherapy management group (OR, 1.12 [95% CI, 0.78 to 1.61]). Sensitivity analysis showed these effects to be similar across other methods of handling missing data except in the case where non-response was imputed as quit.
Changes in Smoking Status of Participants Over Time Among Recipients of Pharmacotherapy Management (PM), Moderate-intensity Disease Management (MDM), and High-intensity Disease Management (HDM).
Self-Reported and Validated Abstinence Among Recipients of Pharmacotherapy Management (PM), Moderate-Intensity Disease Management (MDM) and High-Intensity Disease Management
Secondary, overall (0 to 24 months) analyses, however, showed that self-reported abstinence rates were higher in the high-intensity than in the moderate-intensity disease management group over the course of the study (, ) (OR, 1.43 [95% CI, 1.00 to 2.03]) (no imputation)) and higher in the combined disease management groups than in the pharmacotherapy management group (, ) (OR, 1.47 [95% CI, 1.08 to 2.00] (no imputation)). Comparable findings were seen from the sensitivity analysis, except when all missing values were classified as smoking.
Population-averaged Estimates of the Probability of Quitting Smoking Among Recipients of Pharmacotherapy Management (PM), Moderate-intensity Disease Management (MDM), or High Intensity Disease Management (HDM) (no imputation)
The rate of validation of self-reported abstinence was comparable in the three treatment groups at both 12 and 24 months, indicating that there was no apparent bias in self-reported abstinence associated with more intensive treatment. Cotinine-confirmed abstinence rates at 12 months were 11.3%, and 9.8% in the high-intensity and moderate intensity disease management groups, respectively (OR, 1.24 [95% CI, 0.69 to 2.22]) (). The cotinine-confirmed abstinence rate in the pooled disease management groups was higher than the 5.3% abstinence rate seen in the pharmacotherapy management group (OR, 2.33 [95% CI, 1.24 to 4.38]). Confirmed abstinence rates at 24 months, using either cotinine validation or proxy, were similar among the three treatment groups ().
There were no significant differences in pharmacotherapy costs across the three treatment groups ($209 per participant for pharmacotherapy management and moderate-intensity disease management and $225 for high-intensity disease management, p = 0.64). Over the course of the 24 month study, time devoted to pharmacotherapy and disease management was 0.5, 3.8, and 7.7 hours/participant in the pharmacotherapy management, moderate-intensity, and high-intensity disease management arms, respectively. These differences in counselor time led to significant differences between the three arms in total intervention costs per participant ($231 ± 222 for pharmacotherapy management, $348 ± 236 for moderate-intensity disease management, and $460 ± 289 for high-intensity disease management, p < 0.001).