A randomized clinical trial to determine the effectiveness of CO-oximetry and anti-smoking brief advice in a cohort of kidney transplant patients who smoke: study protocol for a randomized controlled trial

Randomized clinical trial to determine the effectiveness of CO-oximetry and anti-smoking brief advice in a cohort of kidney transplant patients who smoke

Background: measure the efficacy of exhaled carbon monoxide (CO) measurement plus brief advisory sessions to reduce smoking exposure and smoking behaviour in kidney transplant recipients. Methods: Randomized, controlled, open-label clinical trial at a Spanish hospital.Smoking kidney transplant recipients giving their consent to participate were randomized to control (brief advice, n=63) or intervention group (brief advisory session plus measuring exhaled CO, n=59). Measurements: Sociodemographic characteristics, cardiovascular risk factors, treatment, rejection episodes, infections, self-reported smoking, drug use, level of dependence and motivation to stop smoking (Fagerström's and Richmond's test) and stage of change (Prochaska and DiClemente's Stages). Efficacy was assessed at 3, 6, 9 and 12 months as: cotinine test, CO levels in exhaled air, nicotine dependence, motivational stages of change, motivation to stop smoking, pattern of tobacco use and smoking cessation rates. Logistic regression models were computed. Results: At 12 months of follow-up, differences were found in exhaled CO between the intervention and control group(6.1±6.8vs.10.2±9.7ppm;p=0.028). Carboxyhemoglobin levels were lower in the intervention group as well as the positive cotinine test (1.2±1.2%vs.2.0±2.4%;p=0.039),(53.4%vs.74.2%). At 12 months, intervention reduces the probability of a positive urine test by 28%. Conclusions: Co-oximetry is a clinically relevant intervention for reduction of tobacco exposure in kidney transplant recipients.

Effects of Smoking on Solid Organ Transplantation Outcomes

Tobacco smoking is the leading preventable cause of death worldwide. Both donor and recipient smoking have been shown to increase graft loss and mortality in solid organ transplant recipients in many studies. Only in lung transplants is smoking a universal contraindication to transplantation. Transplant centers implement different policies regarding smoking recipients and allografts from smoking donors. Due to scarcity of available allografts, the risks of smoking have to be weighed against the risks of a longer transplant waitlist period. Although transplant centers implement different strategies to encourage smoking cessation pre- and post-transplant, not many studies have been published that validate the efficacy of smoking cessation interventions in this vulnerable population. This article summarizes the results of studies investigating prevalence, impact on outcomes, and cessationinterventions for smoking in the transplant population. We report herein a review of the elevated risks of infection, malignancy, graft loss, cardiovascular events, and mortality in solid organ transplant populations.

Biomedical risk assessment as an aid for smoking cessation

BACKGROUND

A possible strategy for increasing smoking cessation rates could be to provide smokers with feedback on the current or potential future biomedical effects of smoking using, for example, measurement of exhaled carbon monoxide (CO), lung function, or genetic susceptibility to lung cancer or other diseases.

OBJECTIVES

The main objective was to determine the efficacy of providing smokers with feedback on their exhaled CO measurement, spirometry results, atherosclerotic plaque imaging, and genetic susceptibility to smoking-related diseases in helping them to quit smoking.

SEARCH METHODS

For the most recent update, we searched the Cochrane Tobacco Addiction Group Specialized Register in March 2018 and ClinicalTrials.gov and the WHO ICTRP in September 2018 for studies added since the last update in 2012.

SELECTION CRITERIA

Inclusion criteria for the review were: a randomised controlled trial design; participants being current smokers; interventions based on a biomedical test to increase smoking cessation rates; control groups receiving all other components of intervention; and an outcome of smoking cessation rate at least six months after the start of the intervention.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We expressed results as a risk ratio (RR) for smoking cessation with 95% confidence intervals (CI). Where appropriate, we pooled studies using a Mantel-Haenszel random-effects method.

MAIN RESULTS

We included 20 trials using a variety of biomedical tests interventions; one trial included two interventions, for a total of 21 interventions. We included a total of 9262 participants, all of whom were adult smokers. All studies included both men and women adult smokers at different stages of change and motivation for smoking cessation. We judged all but three studies to be at high or unclear risk of bias in at least one domain. We pooled trials in three categories according to the type of biofeedback provided: feedback on risk exposure (five studies); feedback on smoking-related disease risk (five studies); and feedback on smoking-related harm (11 studies). There was no evidence of increased cessation rates from feedback on risk exposure, consisting mainly of feedback on CO measurement, in five pooled trials (RR 1.00, 95% CI 0.83 to 1.21; I2 = 0%; n = 2368). Feedback on smoking-related disease risk, including four studies testing feedback on genetic markers for cancer risk and one study with feedback on genetic markers for risk of Crohn's disease, did not show a benefit in smoking cessation (RR 0.80, 95% CI 0.63 to 1.01; I2 = 0%; n = 2064). Feedback on smoking-related harm, including nine studies testing spirometry with or without feedback on lung age and two studies on feedback on carotid ultrasound, also did not show a benefit (RR 1.26, 95% CI 0.99 to 1.61; I2 = 34%; n = 3314). Only one study directly compared multiple forms of measurement with a single form of measurement, and did not detect a significant difference in effect between measurement of CO plus genetic susceptibility to lung cancer and measurement of CO only (RR 0.82, 95% CI 0.43 to 1.56; n = 189).

AUTHORS' CONCLUSIONS

There is little evidence about the effects of biomedical risk assessment as an aid for smoking cessation. The most promising results relate to spirometry and carotid ultrasound, where moderate-certainty evidence, limited by imprecision and risk of bias, did not detect a statistically significant benefit, but confidence intervals very narrowly missed one, and the point estimate favoured the intervention. A sensitivity analysis removing those studies at high risk of bias did detect a benefit. Moderate-certainty evidence limited by risk of bias did not detect an effect of feedback on smoking exposure by CO monitoring. Low-certainty evidence, limited by risk of bias and imprecision, did not detect a benefit from feedback on smoking-related risk by genetic marker testing. There is insufficient evidence with which to evaluate the hypothesis that multiple types of assessment are more effective than single forms of assessment.

Posttransplant Medical Adherence: What Have We Learned and Can We Do Better?

Purpose of review

Non-adherence to the medical regimen after kidney transplantation can contribute to poor clinical outcomes, and strategies to maximize adherence are sought by care providers and patients alike. We assessed recent evidence on prevalence, risk factors, and clinical outcomes associated with non-adherence to the medical regimen after kidney transplantation. We summarized recent clinical trials testing interventions to improve adherence and generated recommendations for future research and clinical practice.

Recent findings

A large evidence base documents rates of non-adherence to each of the multiple components of the regimen, including medication-taking, lifestyle activities, clinical care requirements, and substance use restrictions. Some risk factors for non-adherence are well known but the full range of risk factors remains unclear. Non-adherence to immunosuppressants and to other components of the regimen increases morbidity and mortality risks. Recent interventions, including education and counseling; electronic health strategies; and medication dose modifications, show promise for reducing immunosuppressant non-adherence. However, most of these interventions would be difficult to deploy in everyday clinical practice. Systematic dissemination of efficacious interventions into clinical practice has not been undertaken.

Summary

Rates and risk factors for non-adherence to the medical regimen have been examined and there is evidence that non-adherence may be ameliorated by a range of interventions. Although gaps in the evidence base remain, it would be timely to devote greater efforts to dissemination of findings. Thus, efforts are needed to assist transplant programs in using existing evidence to better identify patients who are non-adherent and to design and implement strategies to reduce or prevent non-adherence.

Cigarette Smoking and Its Hazards in Kidney Transplantation

Cigarette smoking affects many organs. It causes vasoconstriction through activation of sympathetic nervous system which leads to elevation of blood pressure and reduction in glomerular filtration rate and filtration pressure. It also causes thickening of renal arterioles. Cigarette smoking increases the risk of microalbuminuria and accelerates progression of microalbuminuria to macroalbuminuria. Furthermore, it causes rapid loss of glomerular filtration rate in chronic kidney disease patients. After kidney donation, these factors may be injurious to the solitary kidney. Kidney donors with history of cigarette smoking are prone to develop perioperative complications, pneumonia, and wound infection. Postkidney transplantation various stressors including warm and cold ischemia time, delayed graft function, and exposure to calcineurin inhibitors may result in poor graft function. Continuation of cigarette smoking in kidney transplant recipients will add further risk. In this review, we will specifically discuss the effects of cigarette smoking on normal kidneys, live kidney donors, and kidney transplant recipients. This will include adverse effects of cigarette smoking on graft and patient survival, cardiovascular events, rejection, infections, and cancers in kidney transplant recipients. Lastly, the impact of kidney transplantation on behavior and smoking cessation will also be discussed.