Smoking in Dialysis Patients: A Systematic Review and Meta-analysis of Mortality and Cardiovascular Morbidity

Background: Cigarette smoking is associated with increased cardiovascular morbidity and mortality in the general population, but the effect of smoking on these outcomes in the dialysis population is less well studied. Study Design: Systematic review and meta-analysis of cohort studies. Setting & Population: Adults treated with long-term hemodialysis or peritoneal dialysis. Selection Criteria for Included Studies: Cohort studies of unselected dialysis patients reporting the association between smoking status and cardiovascular morbidity and/or mortality. Predictor: Smoking status (determined using patient report). Outcomes: (1) All-cause or cardiovascular mortality; (2) incident cardiovascular events. Results: We identified 34 studies that fulfilled all inclusion criteria. Of these, 26 studies provided data for smoking and mortality and 10 (n = 6,538) were included in a meta-analysis. The pooled HR for all-cause mortality in smokers compared with nonsmokers was 1.65 (95% CI, 1.26-2.14; P < 0.001). 11 studies provided data for smoking and incident cardiovascular events; 5 (pooled n = 845) were included in a meta-analysis. The pooled HR for composite cardiovascular events in smokers compared with nonsmokers was 1.01 (95% CI, 0.98-1.05; P = 0.4). Limitations: Data for these meta-analyses were heterogeneous. Few individual studies assessed smoking as the primary variable of interest. Conclusions: Active smoking is associated with a significant increase in all-cause mortality in dialysis patients, although there was no corresponding increased risk of cardiovascular events. Am J Kidney Dis. 58(2): 257-265. (C) 2011 by the National Kidney Foundation, Inc.