Abstract
In a nationwide Italian sample of people living with HIV (PLWH), the prevalence of smoking, nicotine dependence, propensity to stop smoking, and cardiovascular profile were investigated. The nicotine dependence by Fagerström test and the propensity to stop according to the stages of change were evaluated. Associations between smoking habits and patients' characteristics were analyzed using an unconditional logistic regression model. Among 1,087 PLWH (age 47.9 ± 10.8 years, men 73.5%), the prevalence of current smokers was 51.6%. The median of Fagerström test was 4 (interquartile range 2–6); 60.1% of the smokers were in precontemplation, 17.6% in contemplation, 18.7% in preparation, and 3.6% in action. In a logistic multivariate model, current smoking was associated with male sex, being divorced/widowed, Caucasian ethnicity, dyslipidemia, atherosclerotic cardiovascular disease risk, psychiatric comorbidity, hepatitis C virus infection, and alcohol abuse. Low high-density lipoprotein cholesterol level was associated with high nicotine dependence. More than 50% of PLWH were current smokers, one-third of them showed a high or very high degree of dependence. Our findings draw attention to the need of smoking cessation strategies for PLWH.
Introduction
Tobacco use is a leading cause of preventable illness and death for all individuals, but it is even more of a concern for people living with HIV (PLWH), who tend to smoke more than the general population. Well treated PLWH may lose more life years through smoking than through HIV. 1 Cigarette smoking increases morbidity and mortality for both HIV and non-HIV-related diseases. Lung and cardiovascular diseases (CVDs) are major concerns, as tobacco use and HIV together may accelerate the development of chronic obstructive pulmonary disease (COPD), lung cancer, and death, 2,3 and smoking is associated with a higher risk of myocardial infarction in the HIV-infected patients than in the general population as well. 4 Characterizing and appropriately managing smoking habits are, therefore, a clinically relevant issue in PLWH.
Current clinical guidelines mandate preventive interventions for lifestyle modification, and are designed to improve the prognosis in HIV-infected patients. 5 Little is known about the characteristics of Italian PLWH smokers, and it is unclear how many of them are really interested in quitting. In other countries, smoking has been associated with age, educational level, illicit drug use, and heavy drinking among PLWH. 6 –8 However, up to date no study about cigarette smoking, nicotine dependence, and related factors has been conducted among PLWH in Italy.
In this study, we aimed at investigating prevalence of smokers, propensity to stop smoking according to the stages of change, nicotine dependence, and quitting rate in HIV-infected patients referring to a network of 10 Infectious Diseases Clinics in Italy. As a secondary outcome, we analyzed factors associated with smoking status and cardiovascular (CV) profile.
Materials and Methods
The study was conducted by the Coordinamento Italiano per lo Studio di Allergie e Infezione da HIV (CISAI, Italian coordinating group for the study of allergies and HIV infection). Patients were enrolled in the “PROJECT STOP Smoking in HIV patients” (see Appendix). A total of 1,087 adult PLWH attending scheduled or unscheduled outpatient visits at one of the centers of the CISAI group were enrolled in the study from July 2014 through September 2016. This article is a cross-sectional analysis of baseline data from the cohort study.
Smoking habits, nicotine dependence, and propensity to stop according to the stages of change were investigated by a standardized questionnaire including the 6-item Fagerström test for Nicotine Dependence (FTND) used to assess the level of nicotine dependence. 9 A score of 0–2 corresponds to very low nicotine dependence, 3–4 to low dependence, 5 to moderate dependence, 6–7 to high dependence, and 8–10 to very high dependence. 10 A score of ≥5 on the 6-item FTND was defined as moderate–very high dependence. If an item was missing, the lowest score was assigned by default, so it was likely that in some patients the total score was underestimated.
Other data regarding PLWH, such as anthropometric measures, blood pressure (BP), history of diabetes, chronic hepatitis, HIV stage according to the Centers for Disease Control (CDC) classification, use of antihypertensive drugs, and lifestyle counseling were recorded using a standard data collection form with the same methods reported in another study by the CISAI study group. 11 Clinical symptoms of COPD such as dyspnea, chronic cough, or sputum production were also collected. 12 Information from laboratory tests included absolute CD4+ T-lymphocyte count, fasting total cholesterol (TC), low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol (HDL-C), triglycerides, plasma glucose concentration, and creatinine levels. Scheduled parameters were collected by a physician.
Among other CV risk factors, hypertension was defined as office systolic BP of ≥140 mmHg and/or a diastolic BP of ≥90 mmHg, or receiving antihypertensive therapy at the time of the index examination. 13 Office BP was measured by a physician in the outpatient clinic and measurement procedures were standardized before starting enrollment as previously reported. 11 The diagnosis of diabetes was based on standard international criteria. 14 Dyslipidemia was defined as TC >200 mg/dL or triglycerides >150 mg/dL or use of statins or other lipid-lowering drugs. Psychiatric comorbidity was defined as having a psychiatric diagnosis and/or being on chronic pharmacological therapy with drugs for anxiety, depression, or psychosis.
Alcohol abuse was defined as alcohol drinking >35 g for day (i.e., 3 U or more, calculated as 1 U = 125 mL wine or 330 mL beer or 30 mL spirits, all containing ∼12 g of ethanol.
The 10-year risk for CVD was estimated using the Pooled Cohort Equations atherosclerotic cardiovascular disease (ASCVD) risk. 15 According to Mdodo et al., 7 “never smokers” were defined as persons who reported smoking <100 cigarettes in their entire lifetime, “current smokers” were defined as persons who reported smoking 100 cigarettes or more during their lifetime and currently smoked every day or some days, and “former smokers” were defined as those who reported smoking at least 100 cigarettes during their lifetime, but currently were no longer smoking. The quit ratio, a measure of successful smoking cessation at the population level, was defined as the ratio of former smokers to ever smokers (i.e., the sum of current smokers and former smokers). The smoking history was evaluated as lifetime smoking exposure, it was quantified in “pack years,” where one “pack year” is defined as 20 cigarettes smoked per day for 1 year. 16 Patients received regular follow-up visits monitoring HIV infection at least every 6 months at the outpatient Infectious Diseases clinics.
All subjects provided informed consent to participate in the study, which was approved by the institutional ethics committee of the coordinating center (Ethics Committee of the Umbria Region) and participating centers. Confidentiality was assured because all patients' information was anonymized, and secured storage was prepared for both paper questionnaires and electronic data set.
Statistical analysis
Categorical and discrete variables were described as frequency (N) and percentage (%), continuous variables as mean and standard deviation (SD, mean ± SD) if normally distributed, and median and interquartile range (IQR) if not normally distributed. In the crude analysis, we used the Pearson or Mantel–Haenszel χ 2 test (as appropriate) to assess the association between categorical variables. Means were compared using the analysis of variance and medians by means of Mann–Withney U test. Associations between smoking habits and patients' characteristics were evaluated using an unconditional logistic regression: odds ratio (OR) and 95% confidence interval (CI) for current and former smoking were calculated using never smokers as reference category. Furthermore, we also calculated ORs of former smokers as compared with current smokers. Continuous normally distributed variables were compared using a general linear model; if not normally distributed, square-root transformation was completed before including them in the general linear model. Multivariable analyses were performed to account for confounding factors. Potential confounders included in the multivariable analysis were age, sex, body mass index (BMI), family history of CVD, risk factor for HIV acquisition [intravenous drug use (IVDU), sexual route, and others], marital status, and education. To avoid the risk of over adjusting, ethnicity was excluded from the adjusted model because it was strongly associated with sex, education, BMI, and risk factor for HIV acquisition. Association of each infection variable and comorbidity with smoking status was estimated in this multivariable model, including them in the model equation as appropriate (i.e., correlated variables were included in turn).
Data analysis was conducted using the statistical software SAS/STAT for Windows (version 9.4).
Results
Overall, 1,087 HIV patients were enrolled from July 2014 to December 2016 in 10 participating centers. Mean age was 47.9 ± 10.8 years, higher in men (48.6 ± 11.1) than in women (46.0 ± 9.6). Men were 73.5% of the whole sample, and most patients were Caucasians (89.2%). The main risk factor for HIV acquisition was sexual route (72.1%), followed by IVDU (22.2%). Forty-three patients (4.0%) were antiretrovirals naive; in experienced subjects, median time of antiretroviral treatment was 9.3 (IQR 3.9–16.0) years.
Prevalence of current smoking was 51.6% and median of estimated pack-years was 21.8 (IQR 12.6–36.0). Pack-years >30 were reported by 35.6% of current smokers. The Fagerström test median value of was 4 (IQR 2–6). The propensity to stop smoking according to the stages of change is depicted in Figure 1: >60% of current smokers were in the precontemplation stage.

Propensity to stop smoking habit in current smokers, according to the stages of change.
Patients' main characteristics according to smoking habits are reported in Table 1. Groups of smoking habits varied in terms of age, sex, marital status, and education, ethnicity, BMI, previous CVD events, diagnosed diabetes and hypertension, ASCVD, psychiatric comorbidity, alcohol abuse (current and former), and hepatitis C virus (HCV) coinfection. With regard to HIV infection characteristics, smoking groups also showed significant risk factor differences for HIV acquisition, CDC stage, and overall antiretroviral therapy (ART) duration. The blood lipids profile was significantly less favorable in current than in never or former smokers.
Characteristics of Sample Population Enrolled in STOPSHIV (n = 1,087)
All data are reported as number and percentage if not otherwise specified.
Mantel–Haenszel test.
Reference: stage A.
Reference <200 cells/mL.
One center did not record this information.
SD, standard deviation; BMI, body mass index; MSM, men having sex with men; IVDU, intravenous drug use; ART, antiretroviral therapy; ASCVD, atherosclerotic cardiovascular disease risk score (10 years); hepatitis C virus positive, antibodies positive for HCV; COPD, chronic obstructive pulmonary disease; CDC, Centers for Disease Control; ART, antiretroviral therapy; TC, total cholesterol, LDL-C, low-density lipoprotein-cholesterol; HDL-C, high-density lipoprotein-cholesterol; IQR, interquartile range.
In a multivariable regression model taking into consideration the covariates of age, sex, BMI, risk factor for HIV acquisition, and family history of CVD, we found that HDL-C and HDL-C/TC ratio were significantly lower in current than in never smokers (p = .044 and p = .040, respectively). Similarly, triglyceride levels were higher (p = .0003). When including years of ART in the equation, these differences were still significant. In this multivariable analysis, antiretroviral duration was not related with smoking status. Similarly, in a logistic multivariate model, with never smokers as the reference category (Table 2), current smoking remained positively associated with male sex, being divorced or widowed, Caucasian ethnicity, family history of CVD, dyslipidemia, ASCVD risk score, psychiatric comorbidity, HCV antibodies, and current and former alcohol abuse.
Multivariable Logistic Analysis: Associations Between Smoking Habits and Patients' Characteristics
The values in bold represents p < .05.
Not age adjusted and sex adjusted.
One center did not record this information.
aOR, adjusted odds ratio; CI, confidence interval; ref, reference category; N, no.; ASCVD, atherosclerotic cardiovascular disease risk score (10 years); hepatitis C virus positive, antibodies positive for HCV.
As expected, symptoms of COPD were positively associated with current smoking. Comparing former and never smokers (Table 2), we observed a largely similar pattern of associations, although some variables lost statistical significance. The estimates regarding COPD symptoms were remarkably lower.
In a further analysis using current smokers as the reference category, being a former smoker was positively associated with older age and higher BMI; an inverse association was observed with IVDU, CDC stage B, and ASCVD score (Table 2). In addition, quitting was inversely associated with psychiatric comorbidities. All symptoms of COPD were significantly less frequent in former than in current smokers.
Overall, the quit ratio for smoking was 27.1% (95% CI 24.1–30.4%). Among current smokers, the dependence degree, depicted in Figure 2, was similar in both sexes. Overall, 176 (31.4%) subjects had high or very high dependence. When comparing smokers with high to those with low-moderate dependence, we found that the former were older (48.4 vs. 46.3 years, p = .02), less educated (34.9% vs. 19.2% with junior secondary, 20.0% vs. 29.5% with college degree, Mantel–Haenszel χ 2 p = .0001), had more frequently IVDU as a risk factor for HIV acquisition (43.2% vs. 26.8%, p = .0005), and were in CDC stage B or stage C rather than stage A (37.2% and 29.6% vs. 29.2% and 23.2%, respectively, p = .003). Lastly, those with high dependence smoked 23.1 versus 12.5 cigarettes per day (p < .0001).

The dependence degree among current smokers by Fagerström test: very low (0–2 points), low (3–4 points), moderate (5 points), high (6–7 points), and very high (8–10 points).
When including these factors in a multivariable regression, we could confirm an independent association between high dependence and low education (adjusted OR, aOR, 3.14, 95% CI 1.79–5.51 for junior secondary education as compared with college degree) and IVDU (aOR 1.69, 95% CI 1.11–2.58 as compared with sexual route).
Finally, smokers with high/very high dependence showed a significantly lower level of HDL-C (46 vs. 49 mg/dL, p = .014), after considering age, sex, BMI, and risk factor for HIV acquisition as potential confounders.
Discussion
Our study contributes to the literature by providing, to our knowledge for the first time, detailed information on smoking habits among PLWH in Italy. The main results of this investigation demonstrated that in a sample of Italian HIV-infected patients seen in routine outpatient clinical care, with an average age ∼50 years and the majority receiving antiretroviral treatment, the overall prevalence of smoking habits was >50%; the level of tobacco smoking was markedly higher in HIV-infected patients than in the Italian general population, 17 in which the prevalence was <20% in the same observational period.
These Italian data are in concordance with previously published research on PLWH from other countries. A recent meta-analysis 18 reported a prevalence of current smoking at 36.3% (95% CI 28.0–45.4) among women and 50.3% (95% CI 44.4–56.2) among men. Consistently with previous research, in our study IVDU, history of major CV events, psychiatric comorbidity, and current or past alcohol abuse 6 were all factors associated with cigarette smoking in HIV-infected patients. Thus, we can reasonably presume that factors related to HIV risk (such as illicit drug use, alcohol abuse, loneliness, depression, and anxiety) mediate the relationship between smoking and HIV infection.
Indeed, a subset of HIV-infected current smokers is exposed to additional major health risks by consuming alcohol and other substances, as is well documented in previous investigations. 19,20 In our study, the degree of nicotine dependence was high or very high (Fagerström test >5 points) in 31.4% of cases. This proportion was lower than that of a previous study from Austria and Germany by Brath et al., 21 which reported a Fagerström test >5 points in 48.4% of smokers in a sample of 221 PLWH. However, as previously stated, in some of our patients, this score might be underestimated.
Regarding HIV parameters, we did not find significant differences between smokers and nonsmokers, with respect to CDC stage, CD4 nadir, and undetectable HIV RNA. Other studies showed that cigarette smoking adversely affects the immunologic response to ART 22 and has a negative association with antiretroviral adherence and positive association with viral load among people with HIV. 23 Conversely, in our sample, current smokers showed a low level of HDL-C and HDL-C/TC than never as well as former smokers. This finding is in line with recent reports showing that smokers have less favorable lipid profiles. 24,25 Smokers with high Fagerström test, that is, those with a more severe nicotine dependence, showed lower levels of HDL-C, a finding that is consistent with the recent investigation by Selya and Hesse. 25
Our results suggest that smoking may be even more detrimental to individuals with hyperlipidemia. Besides, mitochondrial dysfunction and chronic inflammation are induced through oxidative stress smoking. 26 Thus, all these factors negatively clustered for CVDs.
Moreover, in this study, the quit ratio for smoking was 27.1%. This was slightly worse than the quit ratio found in a U .S. study, 7 reporting a quit ratio of 32.4% in HIV-infected patients and 51.7% in the general population. Unlike the report by Tesoriero et al., 19 in STOPSHIV most current smokers answered that they did not want to quit smoking. The majority of participants were in the “precontemplation” phase (60.1%), and only 18.7% and 3.6% were found to be in the “preparation” or in the “action” phase, respectively. Unfortunately, higher dependence levels are linked with lesser expected resolve to stop smoking. 27
Our findings suggest that there is an important unmet clinical need for programs to provide all HIV professionals with the knowledge base for navigating the increasingly complex demands of comprehensive HIV care. This is particularly true in light of the rising impact of HIV-associated non-AIDS conditions in the aging HIV population. Interventions are urgently needed, aiming at reducing codependence of both smoking and alcohol use, even if the expected success rate is low. Understanding and optimizing preventive care in HIV patients are essential in maintaining the substantial advances in prognosis for those subjects. Despite that HIV-infected patients are considered at high CV risk, they still tend to be undertreated for CV prevention; in this setting, counseling to quit smoking represents really a key strategy to prevent CV diseases. 28,29 In our analysis, the estimated risk for future CV events is significantly higher in current smokers than both never and former smokers, so PLWH need to be carefully monitored and counseled in a clinical setting regarding changing behavioral risk factors.
This study has implications for clinical practice. More than 35% of smokers among HIV-infected patients had >30 pack-years (46% of those aged >40 years), thus according to Italian guidelines they are theoretically candidates to annual chest tomography for lung cancer screening. 30
This study has a number of strengths. This study was deliberately inclusive, there was no selection, and a well-characterized multicenter sample of Italian HIV-infected outpatients, followed at Infectious Diseases clinics, were examined, most likely representative of the general assisted population at the same sites. We adopted a standardized procedure for all observed patients. We collected data on smoking habits and clinical information including HIV stage, ART, CD4, and HIV RNA.
However, several limitations need to be discussed. The cross-sectional design and the preliminary nature of our report that is the starting point of a longitudinal study are a primary limitation; the relatively low number of HIV participants older than 65 years on STOPSHIV study represent a second limitation; however, this reflects the current composition of this population. 31 Additional limitation is the absence of laboratory markers of smoking status, our categorization was only based on patient's reported data; however, the smokers' prevalence levels correspond well with measured exhaled carbon monoxide levels reported in another investigation. 21 Moreover, people tend to under- rather than over-report detrimental lifestyle habits such as smoking, 32 thus any bias should tend to lower the retrieved associations. Although in the Fagerström score we did not exclude patients with missing answers, we attributed the lowest possible value to those answers; as a result, also in this case any bias should tend to lower the strength of the observed associations. Lastly, we did not collect data on physical activity.
In conclusion, with longer life expectancy due to better antiretroviral treatment, smoking has emerged as a frequent and life-threatening condition in HIV-infected patients, significantly influencing the life expectancy and quality of life. Italian HIV-infected patients demonstrated a high percentage of current smokers, ∼50% of cases, a large number of cigarettes smoked, and a remarkable proportion of people with high or very high degree of dependence. Our findings emphasize the need of smoking cessation strategies specifically targeting HIV-infected patients.
Authors' Contributions
The study concept and design were by G.V.D.S. Statistical expertise was contributed by E.R. Drafting of the article was carried out by G.V.D.S. and E.R. Analysis, interpretation of data, and critical revision of the article for important intellectual content were performed by all the authors. The authors had full access to the data and take responsibility for their integrity. All authors have read and agreed to the article as written.
Footnotes
Author Disclosure Statement
No competing financial interests exist.
Funding Information
No funding has been provided by any private nor public actor beyond the current clinical practice (provided by the Italian National Health Service).
Appendix
The STOPSHIV group comprises the following members. Coordination: G.V.D.S., E.R., and M.d.’O. Recruitment sites and investigators: Bari (C.S.); Busto Arsizio (B.M., T. Quirino, M. Farinazzo); Firenze (F.V.); Genova (A.D.B., F. Magne); Lecco (C. Molteni); Monza (N.S.); Perugia (G.V.D.S., E.S.); Sassari (G.M., P. Bagella, S. Mameli); Terni (D.F., B. Tiri); and Torino (G.O., M.G.).
