Smoking prevalence in Medicaid has been declining at a negligible rate

Abstract

Background: In recent decades the overall smoking prevalence in the US has fallen steadily. This study examines whether the same trend is seen in the Medicaid population.

Methods and findings: National Health Interview Survey (NHIS) data from 17 consecutive annual surveys from 1997 to 2013 (combined N = 514,043) were used to compare smoking trends for 4 insurance groups: Medicaid, the Uninsured, Private Insurance, and Other Coverage. Rates of chronic disease and psychological distress were also compared.

Results: Adjusted smoking prevalence showed no detectable decline in the Medicaid population (from 33.8% in 1997 to 31.8% in 2013, trend test P = 0.13), while prevalence in the other insurance groups showed significant declines (38.6%-34.7% for the Uninsured, 21.3%-15.8% for Private Insurance, and 22.6%-16.8% for Other Coverage; all P's<0.005). Among individuals who have ever smoked, Medicaid recipients were less likely to have quit (38.8%) than those in Private Insurance (62.3%) or Other Coverage (69.8%; both P's<0.001). Smokers in Medicaid were more likely than those in Private Insurance and the Uninsured to have chronic disease (55.0% vs 37.3% and 32.4%, respectively; both P's<0.01). Smokers in Medicaid were also more likely to experience severe psychological distress (16.2% for Medicaid vs 3.2% for Private Insurance and 7.6% for the Uninsured; both P's<0.001).

Conclusions: The high and relatively unchanging smoking prevalence in the Medicaid population, low quit ratio, and high rates of chronic disease and severe psychological distress highlight the need to focus on this population. A targeted and sustained campaign to help Medicaid recipients quit smoking is urgently needed.

Fig 1. Proportion of US adults in each insurance category.

Error bars represent the 99.7% confidence intervals, used to adjust for multiple comparisons (retaining an overall 95% family-wise error for the 17 surveys from 1997 to 2013).

Fig 2. Smoking prevalence of US adults by insurance coverage.

The top panel: Error bars represent the 99.7% confidence intervals, used to adjust for multiple comparisons (retaining an overall 95% family-wise error for the 17 surveys from 1997 to 2013). The bottom panel: Error bars represent the 99.7% confidence intervals, used to adjust for multiple comparisons (retaining an overall 95% family-wise error rate for the 17 surveys from 1997 to 2013). Data from the 1998 and the later surveys were also re-weighted to the demographic composition (i.e. gender, age, education, race/ethnicity) of the 1997 survey.

Fig 3. Quit attempt rate and 3-month quit rate by insurance coverage.

(A) The average quit attempt rate among those currently smoking or smoking in the past year from 1997 to 2013. Error bars represent the 95% confidence intervals. The weights were also adjusted to the sum of the observed sample size of each survey. (B) The average annual quit rate among those currently smoking or smoking in the past year from 1997 to 2013. Error bars represent the 95% confidence intervals. The weights were also adjusted to the sum of the observed sample size of each survey.