Active Smoking is Associated with Lower Dialysis Adequacy in Prevalent Dialysis Patients

Dialysis adequacy measured by single pool Kt/V (spKt/V) lower than 1.2 or urea reduction rate (URR) lower than 65% is associated with a significant increase in patient mortality rate. Patients' adherence to the medical treatment is crucial to achieve recommended targets for spKt/V. Smoking is a recognized factor of non-adherence.

In this study we sought to assess the association of active smoking and dialysis adequacy.

A total of 134 prevalent dialysis patients from one dialysis center were included in an observational cross-sectional study. Clinical, laboratory and dialysis data were obtained from medical charts in previous 6 months. The number of missed, on purpose interrupted or prematurely terminated dialysis sessions was obtained. Dialysis adequacy was calculated as spKt/V and URR. Patients were questioned about current active smoking status. T-test and Chi-Square test were used for comparative analysis of dialysis adequacy with regard to smoking status.

The majority of patients declared a non-smoking status (100 (75%)) and 34 (25%) were active smokers. Male gender, younger age and shorter dialysis vintage were significantly more often present in the active smokers ((9 (26%) vs 25 (73%), p = 0.028; 57.26 ± 12.59 vs 50.15 ± 14.10, p = 0.012; 118.59 ± 76.25 vs 88.82 ± 57.63, p = 0.030)), respectively. spKt/V and URR were significantly lower and Kt/V target was less frequently achieved in smokers ((1.46 ± 0.19 vs. 1.30 ± 0.021, p = 0.019; 67.14 ± 5.86 vs. 63.64 ± 8.30, p = 0.002; 14 (14%) vs. 11 (32%), p = 0.023), respectively. Shorter dialysis sessions, larger ultra filtrations and higher percentage of missed/interrupted dialysis session on patients' demand were observed in smokers (4.15 ± 0.30 vs. 4.05 ± 0.17, p = 0.019; 3.10 ± 0.78 vs. 3.54 ± 0.92, p = 0.017; 25 (0.3%) vs. 48 (1.8%), p = 0.031), respectively.

Active smokers, especially younger men, achieve lower than the recommended levels for dialysis adequacy. Non-adherence to treatment prescription in smokers is a problem to be solved. Novel studies are recommended in patients on dialysis, to further elucidate the association of dialysis adequacy with the active smoking status.