Pack-Years Smoking History Associated With Lung Transplant Survival

This article is part of Pulmonology Advisor’s coverage of the CHEST Virtual 2020 meeting.

An increased number of pack-years smoking history may decrease the probability of 1-year survival following lung transplantation, according to study results presented at the 2020 CHEST Annual Meeting held virtually, October 18 to 21.

Previous data have shown that cigarette smoking increases the risk of adverse events following transplantations, including related complications, allograft rejections, and mortality. Study researchers sought to examine the effects of smoking pack-years on the 1-year post-transplant survival of lung transplant patients.

This retrospective study consisted of 25,519 patients queried from the UNOS Standard Transplant and Analysis database. All patients were older than 18 years and had a single or double lung transplant between 1987 and 2017. Study researchers organized patients’ smoking history into no smoking history, fewer than 10 pack-years, 10 to 20 pack-years, and more than 20 pack-years. They then adjusted for transplant recipient and donor variables, including age, race, sex, body mass index, and smoking history, and conducted cox regression to determine 1-year survival adjusted hazard ratios (HR).

The median transplant recipient age among all patients was 59 years (47.8% women). A total of 50.3%, 32.9%, 10.2%, and 8.1% of patients reported fewer than 10 pack-years smoking history, no smoking history, 10 to 20 pack-years smoking history, and more than 20 pack-years smoking history, respectively.

Study researchers observed decreased 1-year post-transplant survival in patients with 10 to 20 pack-years smoking history (mortality rate increase, 25%; adjusted HR, 1.239; 95% CI, 1.025-1.498) and more than 20 pack-years smoking history (mortality rate increase, 70%; adjusted HR, 1.707; 95% CI, 1.366-2.132) compared with those who had no smoking history. They noted no significant difference between patients with fewer than 10 pack-years and those with no smoking history.

Regarding adjusted transplant recipient variables, decreased survival was associated with chronic steroid use, greater recipient age, ischemic time of more than 6 hours; increased creatinine levels, and recipient BMI classes of underweight, class 1, and class 2 to 3. Among adjusted donor variables, decreased survival was associated with being male, older donor age, presence of diabetes history, smoking history, and BMI classes of normal and underweight.

The study researchers concluded that, clinically, a “recipient’s [pack-year] smoking history should be considered in selection of lung transplantation recipients given its direct relationship with 1-year post-transplant survival mortality rate.”

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Reference

Choi S, Abu-Ihweij K, Kazi A, Patel K, Patrawalla A. Effect of number of pack-years smoking history on single and double lung transplant survival. Presented at: the CHEST Virtual Annual Meeting; October 18-21, 2020. Abstract 2402.